T H E FA S C I N AT I N G WO R L D O F D R I L L I N G T E C H N O L O G Y
0
5
10
BAKER
HUGHES
20
Over 850 employees are based at the Ger-
in Celle
man branch office in Celle. Eighty percent
T H E FA S C I N AT I N G WOR L D O F DR I L L I N G T E C H N O L O G Y
Products from Baker Hughes and their Functions
15
Baker Hughes around the world and
of those work for the INTEQ division,
Baker Hughes is a world-leading tech-
where drilling systems are developed and
nological corporate group in the oil-
drilling systems and diamond bits are
field service industry. Based in Houston,
produced and marketed internationally.
Texas, the company has a presence in over
Our sales region incorporates central and
60 countries and employs around 27,000
eastern Europe, Russia and central Asia.
people of nearly 100 nationalities. With
Baker Hughes also offers highly specia-
seven divisions linked to its product lines
lized services for drilling rigs (particu-
– Baker Hughes INTEQ, Baker Oil Tool,
larly for directional drilling). Almost 30
Hughes Christensen, Baker Atlas, Baker
percent of our staff members in Celle are
Petrolite, Centrilift, and Baker Hughes
engineers.
Bohrtechnik U engl_RZ 1
Baker Hughes, Christensenstr. 1, D-29229 Celle
www.bakerhughes.com
Tel. +49 (0) 51 41 203-0, Fax +49 (0) 51 41 203-296
www.bakerhughes.de
BAKER HUGHES
Drilling Fluids – Baker Hughes carries out
research and development and works for
all mineral oil and natural gas producing
organizations around the globe.
25
01.12.2004 14:18:28 Uhr
T he Fa s cinating Wor l d of D ri l l ing T echno l og y
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BAKER
HUGHES
20
Over 1,200 employees are based at the
in Celle
German branch office in Celle. Eighty
T h e Fa s c i n at i n g Wo r l d o f Dr i l l i n g T e c h n ol o g y
Products from Baker Hughes and their Functions
15
Baker Hughes around the world and
percent of those work for the INTEQ diviBaker Hughes is a world-leading tech-
sion, where drilling systems are developed
nological corporate group in the oil-
and drilling systems and diamond bits are
field service industry. Based in Houston,
produced and marketed internationally.
Texas, the company has a presence in over
Our sales region incorporates central
70 countries and employs around 36,000
and eastern Europe, Russia and central
people of nearly 100 nationalities. With
Asia. Baker Hughes also offers highly spe-
seven divisions linked to its product lines
cialized services for drilling rigs (particu-
– Baker Hughes INTEQ, Baker Oil Tool,
larly for directional drilling). Almost 30
Hughes Christensen, Baker Atlas, Baker
percent of our staff members in Celle are
Petrolite, Centrilift, and Baker Hughes
engineers.
www.bakerhughes.com
Tel. +49 (0) 51 41 203-0, Fax +49 (0) 51 41 203-296
www.bakerhughes.de
Baker Hughes, Christensenstr. 1, D-29229 Celle
BAKER HUGHES
Drilling Fluids – Baker Hughes carries out
research and development and works for
all mineral oil and natural gas producing
organizations around the globe.
25
T h e Fa s c i n at i n g Wor l d of Dr i l l i n g T e c h n o l o g y
Products from Baker Hughes and their Functions
–5
27,000
Text and Illustrations Matthias Reich, Baker Hughes
Photos Wieslaw Starzewski (pg.14), Marc Kurella (pg. 30)
Design and Art Direction Michael Kalde, www.add-wise.de
© Baker Hughes, Celle, 2004
0.5 bar
853 bar
3km
T h e Fa s c i n at i n g Wo r l d o f D r i l l i n g T e c h n o l o g y
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Second, revised edition
edited by Matthias Reich, 2004
15
20
Introduction 7
C hapter
C hapter
2
C hapter
C hapter
1
3
4
Principles of Drilling Technology 15
What does INTEQ manufacture? 31
2.1 Where is Oil to be found? 16
3.1 Drilling Systems 32
2.2 What does a Rig look like? 18
Drilling Motor (Ultra, X-treme) 32
2.3 What is the structure of a Drill String? 21
Rotary Steering System (AutoTrak) 35
The Bit 21
Vertical Drilling System (VertiTrak) 39
Drill Collars 23
Coiled Tubing Assembly (CoilTrak) 42
Drillpipes 24
3.2 Evaluation Systems 45
Shock-Absorbers, Drill Jars 24
Where are we going? (OnTrak) 45
Stabilizers 25
What do we know about the Rock drilled out? 49
2.4 Well Path 26
Sand or Clay? (Gamma) 50
Vertical Drilling 26
How large are the Pores? (Nuclear) 51
Directional Drilling 28
Is Oil, Gas or Water in the Pores? (Resistivity) 56
Can the Oil or Gas found be delivered? (MagTrak) 57
How good will the Yield from the deposit be? (TesTrak) 59
How reliably and well do we drill? (CoPilot) 61
Can the data flow from downhole to surface be optimized? 64
3.3 Application and Planning Software 68
And Finally 73
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Introduction
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I N TRODUC T ION
–5
“Hello!”
You probably have never thought about it: When you
Houston, in the US state of Texas. Most of the impor-
also provides evaluation tools that survey and moni-
own by the pressure of the reservoir, delivery can be
are sitting comfortably and are not under too much
tant decisions are made there, so it is often necessary
tors the well whilst it is being drilled. This is known as
brought back into swing by using underground pumps
stress your heart beats about 60 times a minute. In
to travel to the USA for business purposes.
MWD (Measurement While Drilling).
from Centrilift.
an hour your heart beats approximately 3,600 times
The Baker Hughes Corporation is not altogether
The borehole has to be cleaned constantly and the
Granted: When considered superficially, many of
a minute, therefore in the course of a working day
easy to comprehend when taken as a whole. It is there-
bits cooled whilst they are drilling. Drilling fluid is used
these services will seem relatively unspectacular to a
(excluding your lunch break) it means about 27,000
fore divided into several handier “divisions”, which
for this purpose. Although, this is supplied by the
layperson. This is probably also why there is so little
times!
offer a wide range of services to the oil and gas indus-
Baker Hughes Drilling Fluids division, many special
general understandable literature on the subject.
try. A detailed description of the work of all the divi-
chemicals and additives are supplied by Petrolite.
However, the deeper you stick your nose into the
so far. But why are we thinking about heartbeats and
sions would soon fill up a whole book. Here in this
details of the different technical areas, the more
That’s quite a lot isn’t it? I hope you are still with me
After drilling, the hole is thoroughly surveyed again
the number 27,000? Now, by chance, the Baker Hughes
introduction, we only intend to give you a brief sum-
with the evaluation systems from Baker Atlas. Now we
fascinating secrets you discover and the more you
Corporation has approximately 27,000 employees
mary of our most important spheres of activity:
really know, quite precisely, what its path is, what it is
are amazed in the end by the technical wonder of
worldwide! Thus every pulse in the course of a long
working day corresponds to a colleague within the
crushed. Hughes Christensen manufactures the bits
Wherever a hole is to be drilled, rock has to be
like, and where the coveted oil or gas is to be found.
the products that have been developed.
Now the borehole is ready, and is stabilized for the
corporation. Would you have known that?
required for this.
life of the well by Baker Oil Tools using a “completion”
right to have its products not only explained to ex-
method that will prevent the borehole from collapsing.
perts but also sometimes to laypeople interested in the
A bit has to turn, otherwise it will not drill. The
different nationalities. Our branches, i. e. offices, work-
drives for the bits are supplied by the INTEQ division,
Baker Oil Tools is also a specialist in “fishing tools”, with
engineering of them. Detailed product material can be
shops, stores and fabrication plants, are located in
to which the company MCT (Motor & Coring Technol-
which any equipment and items which may be lost
found everywhere in plentiful quantities. Now, however,
more than 70 countries all round the globe.
ogy), also still sometimes wrongly called the „rubber
down in the hole can be brought back to the surface.
a start must be made somewhere, therefore this book
works“ or „Elastosystem“, belongs. The INTEQ division
deals especially with the products of the INTEQ Division.
The headquarters of our Corporation is located in
If the oil is no longer forced up to the surface on its
5
10
Each division of the corporation has earned the
Our employees come from a total of almost 100
0
15
20
I N TRODUC T ION
–5
WHERE we are drilling. They also give us information
with extra drive energy, directed at the bottom of the
Many of the yellow/blue, rust brown or silver-colored
large service company which, with approx. 5,500 em-
on WHAT we are drilling (what rock is on the bit and
drill string and thus led to increased drilling speed.
“pipes” on our shelves reveal themselves as real technical miracles when they are investigated more closely,
We, that is, as of now, Baker Hughes INTEQ, are a
ployees and branches in more than 50 countries, is rep-
whether there is oil or gas in it), and also, HOW we are
resented almost everywhere worldwide and would like
drilling (whether the drilling parameters used are set
“directional drilling technology”; the targeted drilling of
but far from all the employees know about this!
to be THE drilling company of choice in the oil and
so that they are the best possible). We also develop
curves using kick-off drilling motors in conjunction
natural gas industry.
and construct these measuring instruments (we call
with “MWD-systems“. In this way, reservoirs (oil/gas
of the Evaluation Systems Department since this prod-
them “Evaluation Systems”) and use them all over the
deposits), where access had previously been difficult,
uct was primarily developed in Houston in the past
We develop, construct, and sell equipment which is
The 80s produced the major breakthrough of
The situation is no better as regards our knowledge
used for producing wells. These are in most cases sev-
world.
became reachable.
and we are therefore less well acquainted with it than
eral kilometers deep, with diameters usually between
with our own drilling tools. The majority of our col-
Our branch in Celle started life in 1957 as a small
The 90s were characterized by “intelligent drilling
6 and 12 ¼ inches. These wells are often of a curved
fabrication workshop making coring bits and, a little
equipment” which could find their own way to or
leagues in Celle have at best a very vague understand-
design, whereby the end of the well runs horizontally
later, diamond bits. In the 70s, the product range was
through the reservoir to an increasing extent. The best
ing of how the complicated evaluation systems in a
through the oil/gas deposit. This area of our activities
extended to cover other components of the drill string.
known representatives of this type are “VertiTrak” and
modern drill string work and what they measure.
is described by the term “Drilling Systems”.
First of all we developed shock-absorbers, which were
“AutoTrak”.
to protect the drill string from damaging vibrations,
and drill jars which could tear loose again any drilling
oped and constructed in Celle, and almost every em-
sible by using elaborate evaluation systems which are
equipment which had become stuck in the borehole
ployee will use the current product designations on a
to give our INTEQ-employees, and all those interested,
taken down the hole, together with the “Drilling Sys-
during the drilling process.
daily basis.
an overview of the products which our company
tems”. These pieces of equipment measure the bore-
manufactures, explain how they work, how they are
hole during drilling, and tell us in this way, exactly
the 70s, these are drilling motors which supply our bits
Modern wells must be positioned very precisely so
10
The first “Navi-Drills” also appeared in the range in
5
10
The present book is intended to help in closing
that optimum production is achieved. This is only pos-
0
these gaps in your knowledge. Of course it cannot pro-
All of these (and many other) products were devel-
vide detailed knowledge in a hurry, but it is intended
But with hand on heart, who really knows how all
these drilling tools work and what they are used for?
15
used, and for what they are used. This book is particu-
11
20
I N TRODUC T ION
–5
larly aimed at those readers who have no, or a very
is brought out of the hole, sent back to one of our
tion about the geology of oil/gas
unclear, idea about the drilling and evaluation oper-
many workshops worldwide, dismantled into its small-
and important stages in the devel-
ation.
est individual components for inspection, carefully
opment of drilling technology.
inspected and repaired if necessary, and then reas-
Not only is the mode of operation of our products
complex, but the extreme conditions in which they are
sembled so that it can be used again.
We hope you enjoy this
used also have to be taken into consideration. The drill-
excursion !
ing process often has to handle temperatures, deep
But it means that our customers can always rely on
Of course, this amounts to an enormous expense.
down in the ground, which we use at home in the oven
receiving the most high-performance and reliable
to cook a pizza. In addition to this, static pressures of
drilling systems in the world.
0
5
500 to 1,000 bar are present (automobile tires are only
pumped up to a pressure of 2 bar), along with violent
So now, follow our colleague in his work clothes
impacts and vibrations, and an aggressive environ-
around the “Baker Hughes INTEQ Drilling Technology
ment in the form of drilling fluid, sharp-edged drilling
Exhibition”. He will guide you and explain to you what
debris, and possibly other chemicals.
a rig looks like, what we mean by the term “directional
drilling”, show you a selection of drilling and evalu-
It is quite obvious that our drilling tools cannot
survive for “a lifetime” in these conditions. No, in our
ation systems which have been developed and con-
industry we are already very satisfied if tools can sur-
structed within our corporation, explain their mode
vive for 150 hours or even a little longer without prob-
of operation in such a way that a layperson can under-
lems and breakdowns. After each use, the equipment
stand it, and at the same time, provide basic informa-
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Principles of Drilling Technology
15
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PR I NC I PL E S OF DR I L L I NG TEC H NOL O GY
–5
CHAP TE R 2 .1
Where is Oil
to be found?
Before we consider how holes are drilled for delivering
move unhurriedly over the globe, no doubt you have
upwards though the fine cracks in the rock in the direc-
oil or gas, we need to think about where oil and gas
read or heard about this. Although this movement
tion of the earth’s surface. In most cases, this succeeds
therefore ask themselves the following questions:
can be found.
takes place slowly, it is unstoppable and causes earth-
and the oil or gas finally escapes unnoticed on to the
quakes, for example where two continental blocks col-
surface.
hydrocarbons which may be rising (for example clay
and complex process from organic material, i. e. from
lide. Strata of the earth push over each other all over
layers)?
plants and plankton.
the place, formerly flat regions are folded together to
strike natural obstacles, for example, impenetrable lay-
Of course, organic material is normally decom-
form mountains, or other areas sink down into the
ers of clay. If these are shaped like a pan lid, relatively
posed by bacteria and becomes earth; you can see this
depths of the earth where higher temperatures are
large deposits can collect underneath them through
in your compost heap at home. However, if the organic
present.
the course of time. The lightweight gas is to be found
material collects at locations where there is no oxygen
in the upper pores and cracks of the rock, the heavier
Is the deposit really oil or gas?
(for example in very deep parts of the seas, or if the
been excluded, is heated to temperatures between
oil will be underneath it, and underneath that, the still
Are the pores connected together so that oil or gas
items of material are layered so quickly one on top of
about 60 and 150°C (because it has sunk down into
somewhat heavier groundwater.
the other that the lower layers cannot be decomposed
deeper rock strata), the conversion to oil and natural
fast enough), then the decomposition process is dis-
gas gradually begins. Whether more oil or natural gas
underground seas, as most people imagine, but rather
Now, we can hopefully obtain answers to the first two
rupted or even prevented. In this way, the organic
forms depends on the exact composition of the bio-
it sits in the fine pores of the rock. Many famous build-
questions from the geologists. Using their measure-
material is retained and is available for the continued
mass and the temperatures.
ings are made of sandstone, like the Semper Opera
ments, a decision is made as to whether a rig should
oil and gas creation process.
Groundwater is usually present in the pores and
House in Dresden for example. This is how you must
be set up and a well “sunk”. We will have to answer the
cavities of the earth. The freshly formed oil and gas are
imagine the rock of the deposit, in the pores of which
subsequent questions in the course of the drilling pro-
lighter than water, and therefore attempt to climb
the raw materials are located.
cess, in that we drill into the potential deposit and take
Oil and natural gas are produced in a long-winded
It is well known that the surface of the earth is not
rigid, but is in constant movement. The continents
16
If the organic material, from which oxygen had
Anyone looking for an oil or gas deposit must
0
Where in the world are there natural obstacles to
However, occasionally, the rising oil or gas will also
Is porous material present under these impenetrable
5
layers, in which oil or gas could have collected?
Are the pores large enough to form a worthwhile
deposit?
10
can flow through the rock to our well?
So the oil or gas is not to be found in the form of
17
15
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PR I NC I PL E S OF DR I L L I NG TEC H NOL O GY
–5
CHAP TE R 2 . 2
What does a
Rig look like?
samples from it. But we will come to this in greater
If the geologists’ measurements
is suspended. The drill string consists of “drillpipes”;
(“string”) drive either takes the form of a “rotary table”,
detail in the chapters which follow.
indicate possible gas or oil in the
these are pipes with a threaded connection on
located under the working platform, or a “top drive”,
ground, a rig is set up, which can
both ends. A drillpipe is usually 10 meters long (the
suspended in the crane hook.
drill into the reservoir, and investi-
Americans prefer to call this length “30 feet”). Depend-
gate it in greater detail.
ing on the height of the rig, before drilling starts, 2 or
duces, must constantly be transported out of the hole,
3 drillpipes respectively are screwed together to form
otherwise it becomes blocked. Therefore, a drilling
large rigs and floating drilling plat-
a “stand”. The 30 meter long stands are sorted into a
fluid (usually a watery sludge) is pumped through the
forms from the colored advertise-
rack, and this allows for the work to go more quickly
drill string down into the hole. The drilling fluid flushes
ments in technical journals as
later when drilling actually starts. Whenever a stand
the cuttings away from the bit and discharges them
decoration: Baker Hughes INTEQ
has been drilled down, the next stand is screwed on
into the ring-shaped space between the drill string and
does not possess any rigs at all, nor
to the drill string. So this becomes longer and longer
the borehole wall (the „annulus“), and up to the sur-
does not manufacture them either!
until the borehole reaches its final length (the techni-
face. Above ground the fluid flows over screen shakers
Nonetheless, the general struc-
cal expert refers to “target depth” or „TD“). Here in
on which the debris is separated out and is then routed
ture of a drilling system will be de-
Germany, boreholes 4 to 6 kilometers deep are usual,
to settling tanks. The fluid, cleared of the cuttings, is
scribed briefly here to enable you
in other countries they can be a few kilometers longer
then returned to the hole for a new cycle.
to have a general understanding
or shorter.
of the drilling process.
pump relatively large quantities of viscous fluid
wise the bit screwed on at the bottom does not drill.
through a long, narrow borehole and back to the
Depending on the design of the system, the rotation
surface (it often has to be several thousand liters per
First of all we need to talk a little bit about the
general principles of drilling technology.
Even if we like to use pictures of
In principle a rig is a crane,
on the hook of which the drill string
18
Of course, the drill string must be rotated; other-
19
0
The drilling debris (or „cuttings“) which the bit pro-
A great deal of energy has to be expended to
5
10
15
20
PR I NC I PL E S OF DR I L L I NG TEC H NOL O GY
–5
CHAP TE R 2 . 3
What is the
t h e bi t
Structure of a
Drill String?
minute). Therefore, the fluid pumps
necessary.
The bit is right at the bottom of the
the bit can turn between approx. 100 to 1,000 revoluti-
on the rig, and the associated die-
drill string. It breaks up the rock
ons per minute, and therefore often rotates several
sel drive units, tend to be more like
rigs. Of course, most drilling platforms also have a resi-
and converts it to cuttings which
million times in the course of its life. It is not unusual
a small truck than a garden pump.
dential unit and a helicopter landing pad, some drilling
are flushed out to the surface with
for the bit to drill a distance of several kilometers in
In principle, that is all that needs to be said about
platforms float, others stand on long legs on the sea
the drilling fluid.
one go, of course, it should remain sharp as long as
a “Blowout” at some time on tele-
bed, but in the end, the general structure is still always
possible, drill quickly, and not wear during this, and if it
vision; that is the most serious pos-
the same.
not produce bits, but our sister
is up to the customer, should also be very reasonably
sible accident which can happen.
company Hughes Christensen
priced.
This takes place when the oil or gas
does. Hughes Christensen is also
shoots up to the sky like a giant,
located on our work site and was
quests can be fulfilled at the same time but rather, as
possibly even burning, fountain. Of
the nucleus of our Celle Works
everywhere else in life, it is necessary
course, something like this should
almost 45 years ago.
to make compromises.
not happen in “real life”. Therefore,
there is a very well thought-out
life. The drill string presses down
rough main groups, rollercone
system of safety valves under the
on the bit from above with a load-
and diamond bits.
working platform, the “Blowout
ing of several tons, under it there
Preventer Stack”. This “stack” can
is the rock, which can often be ex-
suggests, roller cone
be used to reliably control the well,
tremely hard. Depending on the
bits have three
and, in an emergency, shut it off if
type of bit and the type of drive,
rollers
No doubt you will have seen
20
Baker Hughes INTEQ itself does
A bit has an unbelievably hard
21
0
5
Of course, it is quite obvious that not all these re-
10
Bits can be divided into two
As the name already
15
20
PR I NC I PL E S OF DR I L L I NG TEC H NOL O GY
–5
Dr ill Coll a r s
fitted with teeth which crush the stone and mill it into
stalled more often than necessary. This process takes a
pany Hughes Christensen are available at any time to
A drill string, with which a hole perhaps six kilometers
debris. They are relatively cheap to purchase but do
great deal of time and is therefore expensive.
give help and advice in selecting the best bit and en-
deep and less than 30 cm in diameter, is to be drilled
not have an unlimited long life because they contain
suring that the most advantageous compromise of
has a ratio of diameter to length approximately equiva-
ball bearings and many moving parts. After one to two
a lathe, offer a welcome alternative to the rollercone
procurement cost and drilling output is found for the
lent to a relatively long hair. Even though the individ-
days drilling time, in a difficult formation, and with a
bit.
customer.
ual drillpipes are made of iron and apparently seem
high bit loading, a bit of this kind is at the end of its life
despite its precise and robust design. Care must be
the front edges of which, cutting elements made of
structure when considered as a whole.
taken that the rollers do not gradually become loose,
diamonds are fitted. As these bits have no moving
or in an extreme case, actually fall off. In fact, if there is
parts nothing can get lost in the hole, even if used for
pressed forcefully into the rock so that it drills quickly.
scrap in the hole it is not possible to continue drilling.
a long time. That is a clear advantage over rollercone
You, therefore, might think of pressing the string into
Therefore, the missing roller cone must be recovered,
bits. However, the diamonds and manufacture using
the hole from the top of the rig to increase the drilling
using time-consuming fishing procedures, before the
time-consuming manual work are relatively expensive,
speed. However, in many cases this will not work be-
next bit can be fitted. This costs the drilling contractor
so that a “standard” diamond bit costs easily as much
cause the string bends under pressure or in some cases
a lot of time and money and is therefore extremely
as a better quality medium-sized automobile.
even buckles. If this happens the pipe can become
undesirable.
stuck in the hole and, ultimately, can no longer be
The use of diamond bits, which cut the rock as if on
rigid, the entire drill string is an extremely flexible
Diamond bits are equipped with several ribs, on
In the final analysis, which bit is used for which pro-
ject is dependent, first and foremost, on the rock to be
pushed forwards at all.
drilled (the “formation”), and then the conditions of
ing it early enough, but this is problematic because
use in the drilling operation. Each operation must be
generated by a few dozen “drill collars” at the lower
it means that the string has to be removed and rein-
decided individually. The specialists at our sister com-
end of the drill string. Drill collars are particularly thick-
22
23
5
The bit, right at the bottom of the string, must be
cone bit to avoid such occurrences by simply exchang-
Of course, it is possible to limit the life of a roller-
0
10
15
It works considerably better if the bit loading is
20
PR I NC I PL E S OF DR I L L I NG TEC H NOL O GY
–5
Dr ill pi pe s
Shock-A bsor ber s , Ja r s
Sta bili z er s
walled and therefore heavy drill-
The drill string between the drill
It is easy to imagine that when drill-
in an automobile.
products formed a second impor-
The drill string has a smaller diame-
pipes. Part of the weight of these
collars and the crane hook on the
ing hard layers of rock, with bit
tant part of the company in Celle,
ter than the borehole because the
drill collars presses the bit into the
surface consists for the most part of
loads amounting to several tons,
pieces of formation) becomes detached from the bore-
which was still very young at that
flushing liquid (the drilling mud)
rock, the remaining weight ensures
simple pipes which have threaded
and high rotary speeds for the drill
hole wall, and then becomes wedged between the
time.
which is pumped through the string
that the drillpipe above the drill col-
joints at each end so that they can
string, that this procedure can be
drill string and the solid rock in such a way that the
to the bit has to rise to the surface
lars is under tension up to the sur-
be screwed together (see chapter
fairly rough. All of this is normal in
drill string becomes stuck in the hole and cannot be
again outside the drill string.
face and therefore cannot buckle.
What does a drilling rig look like?).
principle though, and our down-
moved. Of course, this is extremely awkward, because
These pipes are referred to as drill-
hole tools are designed for such
in the worst possible case it is impossible to get the
a few points in the drill string to
pipes
conditions.
string free again so that the well has to be abandoned
ensure the drill string has defined
24
Occasionally, the situation arises that rubble (large
and started again at a different position. To minimize
guidance in the borehole. A stabi-
the risk of becoming stuck, usually one or more jars
lizer comprises of a short pieces of
absorb impacts and vibrations or at
are installed in the string. Jars are pieces of equipment
pipe which has several guide pads,
least dampen them so that the drill
which can release heavy blows underground if neces-
the stabilizer blades, around its
string lasts longer and is protected
sary, i.e. close to the problem zone, which are intended
circumference, which hold the drill
from unnecessary damage. These
to tear the drill string free again.
string firmly in the centre of the
shock-absorbers usually involve
borehole. You will no doubt have
strong packages of springs but
absorbers side of the business; we no longer manu-
often seen stabilizers of this type if
sometimes also hydraulic cylinders
facture these products ourselves. However, about 50
you have walked past the shelves
similar to the shock-absorbers used
years ago, alongside the manufacture of bits, these
in the yard at the works site.
INTEQ has withdrawn from the drill jars and shock-
25
5
Stabilizers are integrated at
are often installed in the strings to
Nonetheless, shock-absorbers
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PR I NC I PL E S OF DR I L L I NG TEC H NOL O GY
–5
Chapter 2 . 4
Well Path
V ert ic a l Dr illing
26
So. We have now learnt what a drill string looks like. But
the position of the rock strata in respect of each other,
widely spread out in the horizontal plane (length and
what does a well look like? Is it true that we sometimes
their angle of inclination and the varying hardness of
width) but at the same time only have a shallow thick-
drill curves? And if so, why do we do that?
the rock in the strata. It was possible to influence the
ness. You should not imagine oil and gas reservoirs to
direction of the well slightly via skilled arrangement of
be like underground seas. No, the hydrocarbons (oil
rotating drill string is in itself not very old. It did not
the stabilizers within the drilling assembly. So-called
and gas molecules are consisting of carbon and hydro-
become popular until the beginning of the last century.
building assemblies are used to increase the deflection
gen atoms) are located in the fine pores of the rock and
At that time the rotary drill string only consisted in
of the well from the vertical and drop assemblies to
cannot flow freely in any desired direction. A vertical
principle of the bit and drilling assembly above it
reduce the inclination.
bore, which runs from top to bottom through the thin
comprising the drill collars and the drillpipes which
reservoir therefore only reaches a relatively small
were rotated from on the surface. The drilling mud
were sunk in the area to maximize the delivery of the
amount of oil or gas.
is pumped downwards through the drillpipes to the
field. Photographs from the period around 1900, for
bottom of the hole. Once there it cools the bit and
example, including those of oilfields near Celle at
tional” borehole, as is described in the next chapter.
carries the cuttings out of the borehole back to the
Wietze, are a reminder of what was state of the art at
surface through the annular space between the bore-
that time. The rigs stood side by side as far as the eye
hole wall and the drill pipes.
could see.
The technique of rotary drilling, i.e. drilling with a
The path of a well drilled using the traditional rotary
If a well produced a positive result, additional wells
There was already a suspicion: drilling straight
principle was usually designed to be vertical. In fact, a
down into a reservoir containing oil or gas somehow
genuinely vertical well only succeeded in the rarest of
did not represent the most effective method of open-
cases. The path of the well tended to be deflected by
ing it up. It is true that normal reservoirs are often
Usually better results are achieved with a “direc-
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PR I NC I PL E S OF DR I L L I NG TEC H NOL O GY
–5
Di r ec t iona l Dr illing
Our company, INTEQ, has specialized in drilling
meters away and then drilling runs underground to
“curved” boreholes, on purpose and aiming precisely
the target. The advantages of directional drilling are
at where we suspect the largest pores filled with the
obvious. But of course it is not possible to produce a
best hydrocarbons are to be found. This method, i.e.
directional borehole with a simple drill string with the
controlled drilling of curves and straight sections as
bit screwed to the bottom, but rather extremely spe-
required is called “directional drilling”. We preferably
cialized directional drilling equipment and appropriate
drill downwards using the shortest route to the deposit,
evaluation systems must be used. The development
then horizontally for miles through it. The surface of a
and operation of equipment of this type is our special-
horizontal borehole in the reservoir is enormous in
ity, no other company is close to being able to show us,
comparison with a vertical borehole and correspond-
INTEQ, anything about this subject.
ingly more oil or gas can be delivered.
are so complicated that in most cases we do not sell
Directional drilling also makes it possible to drill
5
Did you actually know that most of our products
many holes in different directions and to open up a
them at all but always only rent them out and send the
complete field in this way from one drilling platform
specialists out with the equipment, thus guaranteeing
without having to move the expensive platform. A
technically correct handling? We talk about “directional
further application of the directional drilling technique
drillers” and “MWD-operators, who have recently also
arises, for example, if a reservoir is under a town or a
become known as “FSE” (Field Service Engineers) for
nature conservation area in which it is not possible to
short. Without FSE on board, directional drilling does
set up a rig. In this case the rig is erected a few kilo-
not even start.
28
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[
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What does INTEQ manufacture ?
–5
]
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W HAT D OE S I N TE Q M A N U FAC T U R E ?
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Chapter 3.1
Drilling
Down hol e Motor (U lt r a, X-t r e m e)
Systems
Now we have learnt so much about what a drill string
torque whilst the drill string only rotates slowly or in
way to that in which people would push their way into
looks like, it is finally time to find out what concrete
other cases does not rotate at all.
a department store through a revolving door.
contributions our company makes to the success of the
borehole.
motors since the 70s and to date our NaviDrills (as we
hole motors can develop a commanding 750 kW (that
INTEQ has been developing and selling downhole
The most powerful representatives of our down-
call them) have always remained a “best in class” prod-
is 1,000 hp!) and, thus, easily put Michael Schumacher’s
ucts can be divided roughly into drilling systems and
uct.
Formula One racing cars in the shade. The fastest types
evaluation systems. The next chapters will introduce
achieve bit speeds of over 1,200 rpm.
you to the most important product lines, explain how
mon with a combustion engine, such as we find in an
they work, and what they are used for.
automobile. Rather, it functions like a “reverse pump”.
Shaft“ of the bearing assembly by a flex-shaft. The
We already said in the introduction that our prod-
Of course a downhole motor has nothing in com-
A pump uses the drive energy to set a liquid in motion.
„Drive Shaft“ forms the output shaft of the motor, and
In contrast, a downhole motor uses the drilling fluid
the bit is screwed into the lower end of it. It is fixed
pressed into the rock) the faster it drills. Therefore the
(which is always being pumped through the drill string
in the bearing assembly by a number of different
faster you turn the drill string the faster you drill, or is
in any case) to generate drive energy for the bit.
bearings.
that not the case?
shape of the rotor and stator in the power section of
the motor which centre the motor stably in the bore-
drill string is of course put under greater strain by the
the motor. The rotor and stator form a large number
hole.
higher speeds and wears correspondingly more quickly.
of closed chambers into which the drilling fluid is
A downhole motor solves the problem, it drives the bit
pumped. The fluid must pass through the motor but it
important detail, namely the kick-off sub on the flex
directly on the spot at a high speed and with high
can only do this by causing the rotor to turn in a similar
joint housing. If the string starts rotating during drilling
Now … unfortunately it is not quite so simple. The
32
This is achieved through the well thought-out
5
The rotation of the rotor is transferred to the „Drive
at the bottom of the hole (and the more firmly it is
To put in general terms: the faster the bit rotates
0
10
Stabilizer pads are often located on the outside of
15
We have not yet mentioned a small but particularly
33
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W HAT D OE S I N TE Q M A N U FAC T U R E ?
–5
Rota ry St e er ing Syst e m (Au toT r a k)
(60 to 100 rpm are usual), the kick-off sub on the motor
whole fleet of motors from the bottom up. The result of
In the previous chapter, the prin-
wells should be drilled more and
only be pushed further forwards
rotates too. This may look a little “eccentric” but other-
this work is the “ULTRA” generation of motors, which is
ciples involved in the operation of
more precisely and at greater
with great difficulty. More and more
wise has no significant effect on the drilling process;
considered the most robust and strongest fleet of
our Navi-Drills was explained, and
speed.
pressure is applied to the string
the downhole assembly drills straight ahead. However,
motors to date in the industry.
especially, also how directional drill-
from the surface until it finally slips
if the string rotation is stopped and drilling continues
ing works with a downhole motor
is permanently in motion because
forward with a jerk. However, a jerk
solely using the drive power of the downhole motor,
the opposite! Since the end of 2002 we have had an
of this type. This principle (drilling
of its rotation and therefore slips
like this can quickly become all too
the kick-off sub which is now pointing stably in a
additional fleet of motors on the market, the so-called
straight ahead with string rotation,
forwards easily. The loading weight
violent with the consequence that
specific direction, causes a curve to be drilled in the
“X-treme” motors with an output which is a further 60
drilling a curve without string rota-
on bit during this operation is al-
the bit is pressed so forcefully into
direction of the kick-off. By joining straight and curved
to 100 percent higher. X-treme motors are used every-
tion) dominated directional drilling
ways under control and can be kept
the rock that the downhole motor
sections together it is possible to realize almost any
where where a “normal” downhole motor reaches its
for many years and was state of the
in the optimum range. Therefore a
stalls. The bit then has to be picked
borehole alignment required.
limits. This involves, for example, particularly jerky
art.
high drilling speed is achieved.
up, off the bottom of the hole, again
applications with severe vibrations, especially hot
before the next attempt can be
boreholes or particularly hard formations.
ing engineers became braver and
drill a curve without string rotation.
made, hopefully this time with
with it and simultaneously navigate the bit through
braver and designed more and
greater success.
the rock.
more complex borehole alignments
kilometer long drill string, usually
The name Navi-Drill, which we use for our down-
hole motors, comes from the fact that we can drill
However, we are not resting on our laurels. Quite
In the course of time, the drill-
During rotary drilling, the string
The difficulty arises, if we try to
If the rotation of a several
and longer and longer horizontal
weighing umpteen tons, is actually
more laborious than rotary drilling
boreholes. At the same time the
stopped for orientated drilling, the
and also proceeds more slowly.
adapted to increasing demands. In the mid-90s the
continuing competitive nature of
string suddenly rests motionless on
Of course, you can try to minimize
decision was even taken to revise and improve the
the oil business demanded that the
the bottom of the borehole and can
the oriented intervals, but it is not
34
35
5
10
Oriented drilling is therefore
constantly during their 30 years of existence and
Of course, our “Navi-Drills” have been improved
0
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W HAT D OE S I N TE Q M A N U FAC T U R E ?
–5
possible to dispense with oriented
therefore, always drills at maximum
and without interrupting the drill-
drilling altogether, certainly not
speed regardless of whether it is
ing process, to make it start drilling
valve is opened so that a part of the
ing in the new direction required.
it clamps itself in the hole via three
when undertaking directional drill-
continuing straight or producing
in a different direction from what it
drilling fluid is squeezed out of the
extending steering pads that allow
ing with downhole motors. Chang-
the desired shape of curve. During
was previously drilling, or for ex-
string.
cation rather complicated? Well,
it to slide forwards and backwards
ing direction without switching off
this, the AutoTrak constantly evalu-
ample to change the radius of a
that might be true at first glance
with the string, but it is practically
the string rotation is not possible.
ates the inclination and direction of
curve. Our engineers have thought
valve is closed again and the entire
but unfortunately it really cannot
unable to rotate with the string.
And that’s all there is to it!
the borehole and not only evaluates out a clever procedure for commu-
drilling fluid is routed through the
be done more simply. This group
A “dot” means that the bypass
A “dash” means that the bypass
our AutoTrak actually continues drill- sleeve does not turn with it. In fact,
You find this type of communi-
vibration in the drill string during
nications from the rig to the Auto-
string to the AutoTrak tool.
of problems will be discussed in
under each of the three extending
the drilling process but also various
Trak-tool in the hole.
greater detail in chapter 3.2.
pads. The higher the oil pressure
development engineer jumped up,
characteristics of the rock and then
First, our directional driller
turbine on board which is driven by
in the cylinder is, the stronger
shouted angrily: “EVERYTHING is
passes this information on to the
enters the command required into
the drilling fluid. As a consequence
topic: how is it possible for AutoTrak
the force is with which the pad is
possible!“ and developed the Auto-
surface.
a computer on the surface. Second,
of the fluctuations in the drilling
to drill in all the directions required
pressed against the borehole wall.
Trak-System, the most elaborate,
the computer codes the command
fluid, which the bypass valve pro-
despite continuing string rotation?
If the oil pressure is approximately
cleverest and most complex drilling
does not only talk to our directional
in that – like using Morse code –
duces, the voltage also fluctuates.
the same in all three cylinders, all
tool ever invented. Using the Auto-
drillers, the communications also
he translates it into a sequence of
The computer in the AutoTrak tool
end of the AutoTrak system, which is the pads will be pressed equally
Trak-System it is possible for the
work in the opposite direction, from
“dots” and “dashes”. The coded
can understand these fluctuations
decoupled mechanically from the
strongly against the wall and Auto-
first time to make any directional
above down into the borehole. The
sequence is now transferred to a
in voltage: less voltage means „dot“,
drill string. In other words: The en-
Trak bores straight ahead. However,
changes required without having to
directional driller can command the
bypass valve at the upper end of the
more voltage means „dash“; thus
tire drill string including the Auto-
if the oil pressure in the cylinders
interrupt the string rotation. It,
AutoTrak drilling system at any time,
drill string.
the „Morse Code“ is decoded and
Trak rotates during drilling; only the
differs, the stronger pads press the
However, the AutoTrak System
36
The AutoTrak tool has a power
But to return to the current
There is a sleeve at the lower
37
5
There is a hydraulic cylinder
statement was made the INTEQ-
But wait a minute! When this
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W HAT D OE S I N TE Q M A N U FAC T U R E ?
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V ert ic a l Dr illing Syst e m (V ert iT r a k)
downhole tool to one side and a
mechanical and hydraulic compo-
the meantime, the design has been revised completely
The main advantage of drilling with string rotation is
corresponding curve is drilled. A
nents plus about 2,000 further elec-
again bearing in mind all the experience gathered. The
that a drill string weighing many tons which rotates
computer controls the oil pressures
tronic components on 25 densely
result of these efforts is our new “AutoTrak 3.0” System,
can be advanced much further into a horizontal reser-
under the pads automatically, so
packed printed circuit boards,
a drilling system which, although it is very similar to
voir than a string which does not move. Secondarily a
that the bore remains precisely on
which in turn were wired together
the “old” system in sofar as its function is concerned, is
rotating drillpipe also swirls the debris about which
the planned course.
by several 100 meters of cable. In
significantly more flexible and even more reliable than
otherwise would settle at the bottom of the hole in
its predecessor because of its modular design.
horizontal boreholes and, in the worst possible case,
A downhole tool with the
capacity to monitor its own three-
could even cause the entire string to become stuck.
dimensional directional drilling
performance and correct it inde-
dimensionally (can drill in all directions) and was de-
pendently if necessary (i.e. without
signed for relatively small borehole diameters such as
intervention by the directional
are usual when drilling into deep reservoirs.
driller) did not exist previously in
commercial drilling technology.
production well can be drilled, it is necessary to pro-
AutoTrak has thus entered new
duce the vertical part of the hole, which is also often
territory as regards to technology.
several kilometers long (from the ground level down to
the deposit). In this upper section (the technical expert
The first AutoTrak downhole
10
However, before the long horizontal section of a
refers to the “Top Hole“) the hole should simply have
and consisted of more than 1,000
a path which is vertical and as straight as possible be-
39
5
AutoTrak is enormously flexible, thinks three-
tools were about 12 meters long
38
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W HAT D OE S I N TE Q M A N U FAC T U R E ?
–5
cause this is the shortest and fastest way to the target.
way that it can work entirely without string rotation.
Adhesive friction does not occur in a vertical hole (or
System is used, it is an advantage to have as many sen-
nificantly cheaper. AutoTrak always
only to a minor extent) and no debris can settle on the
rotate!“, we hear all of you shout at once. Yes, that is
sors in the string as possible which tell the directional
drills in rotary mode with string
underside of the hole because there is no underside.
correct. And therefore VertiTrak has a power section
driller whether the borehole is still in the area of the
rotation and in this way can get
String rotation is not required to drill the top hole sec-
like the one already described in the section about
most promising oil or gas yield. In the top hole, where
anywhere. In contrast, VertiTrak
tion!
drilling motors. It must be extremely powerful because
the non-rotating VertiTrak System is used, in contrast,
drills entirely without
INTEQ has developed the VertiTrak System espe-
the upper part of the hole has a much larger diameter
it is relatively unimportant as to which rock types are
string rotation and only
cially for drilling the top hole, an automatic drilling sys-
than lower down in the reservoir, and therefore a great
being drilled through at the time. The important thing
ever vertically down-
tem which makes its way down to the reservoir by the
deal of stone has to be crushed.
is to drill down as fast as possible. Therefore VertiTrak
wards. In Argentina, for
shortest route. Without string rotation, the walls of the
can also manage without having expensive sensor sys-
example, the rock for-
borehole are hardly subject to any mechanical stress,
part of the housing (similar to AutoTrak). It uses these
tems on board.
mations lie at such an
there are no breakouts, and the entire hole remains
pads to push itself back, again and again, to a vertical
oblique angle over the
much smoother and in gauge. Employees from Celle
position as soon as the smallest deviation of the hole
tion of the hole but simply has to keep the inclination
reservoir that all the con-
will still remember the predecessors of today’s Verti-
from the vertical occurs. The hydraulic oil pressure for
constantly on “zero”. Therefore, VertiTrak does not
ventional downhole sys-
Trak system under the designations “Vertical Drilling
operating the control pads is generated by a pump in
need such a complicated “brain” as its little brother
tems were kicked-off
System (VDS)“ and “Straighthole Drilling Device (SDD)“
the head of the drilling system. The inclination sensor
AutoTrak does for its complex, three-dimensional “
sideways and could only
from the days of the famous KTB research borehole in
and the evaluation and control electronics are also
designer boreholes”.
be brought back to the
the early 90s.
located there which constantly allocate the correct oil
target path by consider-
pressure to each pad to keep the well vertical.
brother of AutoTrak. It is much stronger, less intelligent,
So, as we have said, VertiTrak is designed in such a
40
”But just a minute... the drill bit at least must still
The VertiTrak System has three pads on the lower
but therefore very robust and sig-
Down in the reservoir, where the rotating AutoTrak
VertiTrak does not need to worry about the direc-
As a whole, VertiTrak is, so to speak, the fat big
0
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able correction work
41
20
W HAT D OE S I N TE Q M A N U FAC T U R E ?
–5
Coil ed Tu bing Asse m bly (CoilT r a k)
which takes a great deal of time and
“Coiled Tubing” means just what it
what different. Entering the borehole
when drilling can finally start, in some
is only possible to take relatively
fied with it – except for one: Our
money. Only VertiTrak is able to drill
says. Exactly what that is will be de-
means first of all an apparently end-
circumstances the bit is already blunt
small drilling motors down it. The
directional driller is looking rather
directly down into the target area
mystified shortly. But, first of all a few
less process of screwing the drillpipes
after one day and everything has to
holes drilled with the system are cor-
distressed. Namely, there is no drill-
without correction. In this way we
other things.
together. A “stand” (see chapter
be removed and reinstalled again.
respondingly small and have a maxi-
pipe to steer any more! Even if you
Introduction) is usually 30 meters
(100 ft) long. If a depth of four kilo-
the drilling contractor in desperation.
roughly 10 cm.
remind you: A bit and a kick-off motor meters is to be drilled, therefore 130
“Is it not possible to get through the
are used to enable the system to be
threaded joints must be screwed
whole four kilometers in one go
drilling system on this
steered in every desired direction via
together one after the other and
somehow? Like a garden hose being
“steel garden hose” and
the drillpipe, just like using a steering
lowered into the borehole before the
wound on to a reel?“
unroll it, we will be at
wheel. This is the same principle as
bit finally arrives at the bottom and
the bottom of the hole
driving an automobile, except that of
drilling can commence. This means
some drilling applications. In fact, this
in a trice without
course the directional driller must
that the protection caps must be
is how the first Coiled Tubing Systems
having to screw threads
remain on the surface whilst the hole
removed from each section; the
save the happy customer several
weeks’ expensive drilling time on
situation with directional drilling. To
each well.
“In the beginning was …”, the
„Oh … the cost of it all !”, screams
This idea is not at all wrong for
mum diameter of 4 1/8 inches, i. e.
5
Now if we hang our
were set up, the drill string of which
together. The four kilo-
gets deeper and deeper. It is then only thread must be lubricated, screwed
actually consisted of long steel hoses
meters can be man-
necessary to trip the drill string in the
together and torqued up to the cor-
wound on to large reels instead of
aged by one single
hole and start drilling. Or is it?
rect value. An installation of this type
individual drillpipes. Since more flex-
man in less than five
requires 3 people working for a half
ible tubing is also thinner and there-
hours winding time!
the drillers, the matter may look some- day without interruption. And then,
fore weaker than a “normal” string, it
Now … from the point of view of
42
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Everybody is satis-
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W HAT D OE S I N TE Q M A N U FAC T U R E ?
–5
Chapter 3. 2
Evaluation
W h er e A r e W e G oing ? – OnT r a k
Systems
could turn the entire reel with the
hole motor itself is to be found. So
the hole path, the nature of the rock
made to crank production up again.
We learnt in the preceding chapters
uncoiled pipe at the top of the well,
the directional driller on the rig only
and the strength of the vibrations
One possibility, which is frequently
how drilling of curves is undertaken. including a plumb line and a com-
the flexible steel hose would be too
needs to move a joystick to the left or
underground (you will find the
utilized, is designated “Re-entry
But how do we actually know where pass.
elastic to pass on a steering move-
right and the kick-off drilling motor
details of how that works in chapter 4
Drilling”. During this process one or
we are drilling? What tells us if we
ment downwards to direct the kick-
deep down in the hole turns in any
of this book) and send these data via
more sideways “arms” are drilled
are on the planned drilling path or
System is instantly noticeable be-
off on the motor.
direction required.
the cable to the surface in real time.
from the existing well into areas of
whether we have perhaps acciden-
cause, unlike most other tools on
That means that every deviation from
the reservoir which had previously
tally come off course? Our direc-
our shelves, there is no rust at all on
So how can the motor be turned
The coiled tubing pipe therefore
various electronic evaluation tools,
The outer tube of an MWD-
in the direction required to drill a
contains a power cable which con-
the planned drilling path and every
been disregarded. Re-entry holes of
tional driller is still sitting on the
it because it is made of special non-
curve?
nects the special drilling assembly
interruption to the smooth drilling
this type are an ideal area of applica-
surface on the rig whilst the bit is
magnetic steel. As is well known,
(we call it CoilTrak) directly to the
operation can be detected immedi-
tion for our CoilTrak System, because
burrowing through the rock several
the compass needle, which is to
gant solution, the hydraulic orienter.
control station on the surface. In
ately by the directional driller and
they must be undertaken quickly and
kilometers below us. How can the
measure the direction of the well,
The coiled tubing hose has a fixed
addition to the power supply for the
corrected.
at a reasonable cost and must man-
directional driller see what is going
attempts to align itself with the
length with no thread. It is perfectly
orienters, this cable link also offers an
age with little space on the surface.
on “down there”?
weak magnetic field of the earth,
possible to insert an electric cable
elegant facility for “online“ transfer of
application for our CoilTrak drilling
which is still present, even deep
into a hose of this type with which a
every possible item of evaluation
assembly is the many old wells, deliv-
about the path of the borehole is
underground. “Normal“ steel in
small oil pump is operated under-
data from the hole to the surface.
eries from which have dropped to
provided for us by the “MWD“-Sys-
the area of the compass needle dis-
ground. The hydraulic oil from this
The CoilTrak drilling assembly is
the boundaries of economic viability
tem. MWD stands for “Measurement rupts this measurement or makes it
pump moves a piston to the right or
therefore fitted with a number of
in the course of time. Instead of clos-
While Drilling“. The MWD-System
totally unusable and therefore may
left, on the end of which the down-
sensors which measure, for example,
ing these wells, an attempt can be
consists of a tube which contains
not be used as the housing for the
Our engineers developed an ele-
44
A particularly interesting area of
45
The answer to the question
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W HAT D OE S I N TE Q M A N U FAC T U R E ?
–5
MWD-System. The plumb line
0 degrees and a horizontal one the inclination 90
information to control the drilling operation.
stantly through the drill string to the bit to pick up the
measures the inclination of the
degrees etc.).
cuttings there and deliver them to the surface through
borehole. The drilling
engineers have agreed
that a vertical hole
has the inclination
tion on what the hole drilled to date looks like, whilst
the annular gap between the drill string and the bore-
to the drill string, the MWD-System uses the short
the toolface determines the direction in which drilling
hole wall.
moment of stillness in the borehole to measure the in-
will continue. To realign the kick-off sub on the motor
clination and direction particularly precisely. The tech-
(the „toolface“), the directional driller simply turns the
(i.e. opened and closed) by a computer, also housed in
drill string (and therefore also the downhole motor)
the MWD. If the valve is “closed” (one part of the flow
Our directional driller on the rig calcu-
cautiously a little to the left or the right.
cross-section still remains free …), the pumps at the top
lates the precise path of the borehole
One further question arises: the MWD is at the bot-
on the rig must generate more pressure to keep the
to date from the survey data.
tom of the hole, maybe several thousand meters deep
fluid in motion than is the case with the valve open.
Apart from the inclination and the
whilst the directional driller is standing at the top on
Thus the valve can generate fluctuations in pressure in
direction (“azimuth”) of the borehole,
the rig. How do the measured values actually go from
the drill string by opening and closing. The expert pre-
the MWD-System also has the task of
the MWD to the directional driller?
fers to talk about “pressure pulses“, therefore, the valve
in the MWD is called a “pulser valve“.
Whenever a new run of drillpipes is screwed on
nical expert talks about performing a “Survey”.
establishing the direction in which
As data transmission by cable in the screwed to-
hole motor, the “Toolface“
proved problematical, it was possible to implement a
How is that meant to work?
is pointing at that precise
different variation: the transmission of the measured
moment because our direc-
values in the form of targeted pressure fluctuations in
a “binary code” by a computer in the MWD. This is the
tional driller needs this
the drilling fluid. As you know, this is pumped con-
computer language which, instead of consisting of
47
0
Now, there is a valve in the MWD which is operated
gether drill string or via radio through the rock has
the kick-off sub of the down-
46
Inclination and azimuth therefore provide informa-
5
10
But … a valve that can transmit measured data?
15
First of all, the measured values are converted into
20
W HAT D OE S I N TE Q M A N U FAC T U R E ?
–5
W h at Do W e Know A bou t T h e Rock Dr ill e d Ou t ?
many different letters or numbers, only consists of
the evaluation equipment to operate it on site, ensures
pores (this will be described in
OK, we know now where we are
zeros and ones. It is a similar situation to Morse code
that the entire data transfer runs smoothly and checks
greater detail in the following
drilling to. But the drilling path
establishing when drilling the cur-
which of course only has dots and dashes but yet any
whether the data transferred are complete and correct.
chapter). Finally, a vibration module
originally planned is not always the
rent path of the well is advantage-
desired words and sentences can be transmitted with
The crews on the rig do not notice much of the whole
indicates whether the drill string
best one. For example, the reservoir
ous or whether it would be better
it. So the computer begins to open and close the valve
procedure. They only look at the digital display on
with the sensitive evaluation sys-
could in fact be a little higher or
to modify it a little?
in a specific time sequence. For example, the open
the rig and, together with our directional driller, are
tems is rotating evenly deep down
lower than the geologist thought.
valve stands for a zero, the closed one for a one.
delighted with the measured values shown.
in the hole or is vibrating danger-
If in this case we stick stubbornly
yes, we can find out! Modern drilling
Is there perhaps some way of
I’m sure you already suspect it:
ously.
to the original path planned for the
assemblies have a wide range of
ure rises in the entire drill string. When the valve opens,
addition to the sensors already described for procuring
well, in the worst case we might drill
well thought out evaluation systems
the pressure drops back to its original value. Right at
the directional drilling information (inclination, azi-
hidden in some of the “tubes” on
past the reservoir altogether! Or
on board which enable us to obtain
the top of the drill string (about where our directional
muth and toolface) it has further “sense organs”. The
the shelves you see on our com-
it could be that by chance, at the
valuable information about the
driller is waiting for his data) there is a pressure sensor
measurement of the pressures in the drill string and in
pany site. Could you have imagined
particular point in the reservoir in
nature of the rock in the hole. If the
which measures the pressure fluctuations in the drill
the borehole gives information about the stability of
that?
which we want to place the well,
path of the borehole is constantly
string and passes them on to a computer connected to
the borehole and tells us whether the discharge of the
the pores in the rock are particularly
optimized during drilling on the
the system. This evaluates the measurement by first of
debris from the hole is working in the best possible
thin and we would therefore only
basis of the results of the evaluation,
all decoding the binary code (much pressure = “1”, little
way. The measurement of the natural radioactivity and
be able to deliver a very small
the technical expert calls this „Geo-
pressure = “0”) and then converts it into actual mea-
conductivity of the rock enables information to be
amount of oil, whilst a few meters
steering“.
sured values for azimuth, inclination and toolface. The
gained on exactly which rock is being drilled at present
to the left or right, the really good
“MWD-operator”, an expert who is sent together with
and whether gas, water, or oil is to be found in the
big pores remain unnoticed.
you will learn about the most impor-
Whenever the valve closes in the MWD, the press-
48
Our most recent MWD-System is called “OnTrak”. In
Well, so much technology is
49
0
5
10
15
In the chapters which follow,
20
W HAT D OE S I N TE Q M A N U FAC T U R E ?
–5
Sa nd or Cl ay ? (Ga mm a)
How l a rge a r e t h e Por e s ? (N ucl e a r)
tant of our „Formation Evaluation“
At the beginning of this book we
counter! No doubt you know this
significantly more intensively than
The oil or gas of the reservoir sits in
pores are actually filled with.
measuring systems.
described how and where oil and
sort of equipment from physics les-
sand. When the Geiger counter on
the pores of the rock. It is therefore
gas can be created. It was explained
sons at school, it is used for mea-
board (in the technical world it is
entirely obvious that rock which has
determination of the porosity is not
there that the oil or gas tends to col- suring radioactivity. If the teacher
called a “gamma detector“) reports
larger pores can also contain more
simple and our scientists had to dig
lect in sandstone under “covers” of
had held the Geiger counter against
relatively strong radioactivity, then
oil or gas. If, on the other hand, the
very deep in their bag of tricks to
clay. As the gas is the lightest, it is to
a hidden radioactive sample, which
we are moving towards the clay
pores are thin, we will not be able to
find a suitable measuring principle.
be found at the top in the reservoir,
no-one was allowed to touch, the
layer and had best move away. On
pump any large delivery flows above
Oil and gas are “hydrocarbons”, that
i.e. particularly close to the clay
Geiger counter would have started
the other hand, if the gamma de-
ground from this rock. Therefore the
means, they consist of carbon and
layer above it. Therefore it is partic-
to crackle like mad.
tector is quiet, we are drilling in the
measurement of the pore size during hydrogen atoms which have com-
ularly useful when drilling for natu-
sand.
drilling provides extremely impor-
bined together in specific arrange-
ral gas to have a sensor in the drill-
perhaps now ask, can a Geiger
tant information whether we are in a
ments to form chains or rings.
ing assembly which can inform the
counter distinguish between sand
“good“ or „bad“ area of the reservoir.
directional driller, on the surface,
and clay? How does it do it?“
call it H2O) also contains hydrogen
whether the drilling assembly, far
developed the “APLS“. APLS stands
(a water molecule consists of one
below in the earth, is still in the
many types of rock are naturally
for “Advanced Porosity Logging Ser-
oxygen atom, which so to speak
sand of the deposit containing gas,
slightly radioactive. This is normal,
vice“. Anyone who uses this service,
holds a hydrogen atom with each
or is in the clay cover above it.
and quite safe to humans. Different
not only receives an evaluation of
hand).
formations also emit radiation to
exactly how porous the deposit is,
different degrees, clay, for example,
but also information on what the
oil, gas, or water is present in the
There actually is a sensor which
can do that! This involves a Geiger
50
“Just a moment“, you will
The answer is easily found:
Therefore, our engineers have
51
0
Granted: the underground
5
10
Water (as you know, the chemists
15
Therefore, regardless of whether
20
W HAT D OE S I N TE Q M A N U FAC T U R E ?
–5
pores, there will always be hydrogen atoms present. In
After for example 10 collisions with hydrogen atoms, the
at their last gasp.
contrast, the surrounding rock contains practically no
entire energy of the neutron has fizzled out. You remem-
hydrogen.
ber of course: hydrogen only occurs in the pores. The
pores” in the rock, little energy means “pores with oil”,
more pores there are in the rock, consequently the more
and even less energy means “pores with water or gas”.
demics concluded, can therefore be used as a scale for
neutrons give up, exhausted on their way through the
its porosity: no hydrogen – no pores, a lot of hydrogen –
rock.
still not satisfied because this “simple” measuring prin-
lots of pores. That is good because the proportion of
ciple on its own is open to too many possible interpreta-
hydrogen in the formation can actually be measured if
a few pores in the rock) the neutron does much better.
tions. For example if the energy content at the detector
you use an artificial radioactive source and a detector.
Here it is brimming over with energy even after one
drops this can mean that
The proportion of hydrogen in a formation, the aca-
In a low hydrogen formation (i.e. if there are only
That’s very neat isn’t it? However, our specialists are
or two hundred collisions with the atoms of the rock.
a) either the proportion of pores becomes larger and tive substance, to put it more precisely a neutron source,
is held against a sample of rock. Neutrons are a constitu-
A detector is installed at a specific distance from the
b) or the pores do NOT become larger rather there is ent part of radioactive atoms. They release themselves
neutron source which measures how much residual
simply more water (and therefore less oil) in the from the radioactive source and shoot into the environ-
energy the neutrons still have after their migration
pores because water swallows up more energy than ment with great energy. They bounce off the atoms
through the rock. In poreless rock the neutrons arrive
oil or gas.
which they meet on their way through the rock. Each
at the detector full of energy. In contrast, in porous rock
How unfortunate, you could think, because you still can-
impact process causes a part of the original energy of
the few neutrons arriving are significantly more “lifeless”.
not be sure! Which of the two answers is the right one?
the neutron to be lost. A collision with a hydrogen atom
In gas they can just survive but if the neutrons have to
costs the neutron a particularly large amount of force.
pass through pores which contain oil or water they are
tion ready. Not only are there radioactive sources which
Let us have a look at what happens when a radioac-
52
Now this effect can be used to measure porosity.
53
0
So a great deal of energy at the detector means “no
therefore more hydrogen is present in the rock,
5
10
15
But of course our scientists soon had another solu-
20
W HAT D OE S I N TE Q M A N U FAC T U R E ?
–5
Is Oil , Ga s or Wat er in t h e Por e s ?
(R e sist ivi t y)
emit neutron beams but also those which emit gamma
porous the rock is, the more often the gamma radiation
the porosity and the distribution of the contents of the
It has already been mentioned in the preceding chap-
radiation. Gamma radiation has quite different charac-
strikes atoms of the rock on its way to the detector and
bores along the borehole can be produced from the
ter that a radioactive source can be used to established
teristics from neutron radiation. You could compare
the weaker the signal at the detector is. This is exactly
different signals of the two detectors. The designation
whether there are any pores at all in the rock and how
neutron radiation to billiard balls which collide with
the opposite to the situation with neutron radiation.
APLS (Advanced Porosity Logging Service) actually
large these are. It is even possible to establish to a cer-
other balls (atoms) and cause these to move. This is why
strikes the core of the matter precisely.
tain extent what is hidden in the pores. However, han-
the neutron loses a little energy with each collision. In
(neutron and gamma radiation) now finally produces
dling radioactive sources is naturally not without its
contrast, gamma radiation has no mass (generally re-
the full picture required. If we assume, for example, that
be: inexpert handling of the radioactive sources is
hazards and it is better to avoid it if possible.
ferred to as “weight”) like a billiard ball and cannot
we are drilling from an area with oil-filled pores into an
always dangerous! If they are not in use they must
therefore push forward any nuclei. Instead, however,
area of water-filled pores (which is normally undesir-
be stored in special containers and may only ever be
taken without using radioactive sources. For example
gamma radiation can cause the electron cloud of an
able), but the porosity remains the same, it becomes
handled by specially trained technicians. This is taken
if you only want to know whether the pores contain
atom it meets to “swirl about” or can even tear individu-
apparent because the detector shows that the energy
to the extent that the entire working area on the rig has
the coveted oil or gas or only (salt) water, then a simple
al electrons out of the cloud. You remember that an
from neutron radiation has decreased, whilst the energy
to be evacuated when radioactive sources are being in-
radio transmitter in the drill string can do amazingly
atom consists of a nucleus and an electron cloud which
on the gamma radiation detector remains constant.
serted in the evaluation unit or removed from it by the
good work.
circles around this nucleus. During this “swirling about”
technician. The Emperor of China could come to inspect
by the electron cloud, the gamma radiation loses ener-
oil but are getting smaller and smaller (which is also
the rig, but he would be prevented from accessing the
which is picked up again by two receivers at different
gy, the radiation is weakened. It is fortunate for our
undesirable) as the borehole progresses, the energy at
working platform and the surrounding area because
distances away. Oil is a relatively poor conductor of
measurement that gamma radiation reacts first and
the neutron detector increases (fewer hydrogen atoms)
safety always takes precedence!
electricity; therefore, it is also difficult to transmit radio
foremost to the atoms of the rock and much less to the
and falls at the gamma detector (more rock).
waves through it. In contrast, salt water is an excellent
atoms of the substances contained in them. The less
conductor of electricity and radio waves. Depending
54
The combination of the two evaluation systems
In contrast, if the pores in the rock remain filled with
However elegant the two evaluation systems may
So, with a little brain work, sensible information on
55
0
5
Some measurements can actually also be under-
10
The transmitter transmits a certain radio signal
15
20
W HAT D OE S I N TE Q M A N U FAC T U R E ?
–5
C a n t h e Oil or ga s found
be deliv er e d ? (M agT r a k)
on whether the pores in the area of the evaluation sys-
Have you ever seen a magnetic resonance tomograph?
netic Resonance“), is a complex measurement which,
measuring methods but to do this we would always
tem contain oil or water at the time, reception is better
If so, it was probably in a hospital. A device of this kind
although it can only be implemented underground at
need several items of evaluation equipment at the
or worse.
is about 2 meters high and 3 meters long; an enor-
great expense, does permit a number of different char-
same time, some of which also contain radioactive
mous monstrosity.
acteristics of a reservoir to be investigated at the same
sources. In contrast, the NMR-measurement manages
“conductivity” of the rock, its reciprocal value is nor-
time. With MagTrak (that is the name of our evaluation
to do this without using radioactivity, even though the
mally used, the “resistivity”. If the conductivity is high
resonance tomograph, you cannot only take photo-
system) we can measure the porosity of the formation,
word “Nuclear“ is part of its name. In this way, it forms
(salt water in the pores) the resistivity is low and vice
graphs of sections through the body but you could
determine the permeability of the rock (i.e. whether
an important alternative to the classic porosity mea-
versa. In principle, our experts on the rig only need to
also undertake very interesting measurements in the
the pores are connected together in such a way that
surements without the burdensome risks and safety
assess the quality of the reception to draw conclusions
borehole if you could somehow force the monster
the oil or gas can flow) and establish the distribution of
requirements.
about the nature of the natural resources found.
machine down there. Most boreholes actually only
the pore sizes within the rock. In addition, a distinction
have a diameter of 15 to 20 cm.
can be made between the fluids in the rock (oil, gas
behave like small magnets, which means, that like a
In the technical world, instead of talking about the
56
Why am I talking about this? Well with a magnetic
and water) and their respective proportions can be cal-
compass needle, they always align themselves so that
culated. As a consequence, we are in a position to give
they point in the direction of the magnetic field lines.
remained unsolved for a long time, but - I am sure
our customers a better answer to a few of their burning
Hydrogen atoms have this characteristic for example.
you have guessed – the engineers from INTEQ finally
questions: Is oil or gas present in the deposit and, if so,
As hydrogen is to be found in practically all the pores
cracked this problem too.
how much? And how effectively can the oil or gas be
in the rock (i.e. in water, oil, and gas), this characteristic
produced?
can be used for various measurements.
magnetic resonance tomography (we usually tend to
call it „NMR“, that is the abbreviation for „Nuclear Mag-
we can answer almost all of these questions with other
In comparison with other measuring methods,
OK, in the preceding chapters we have learnt that
5
Well how does MagTrak work then? Some atoms
graph for these dimensions was a problem which
In fact constructing a magnetic resonance tomo-
0
10
15
Hydrogen atoms, in the pores, are all aligned in the
direction of the earth’s magnetic field. Now, if an artifi-
57
20
W HAT D OE S I N TE Q M A N U FAC T U R E ?
–5
How G ood W ill T h e Produc t ion
From T h e R e servoi r Be ? (T e sT r a k)
cial magnetic field is suddenly
in the pores.
In order to be able to evaluate
beginning of the measurement, a
pore pressure can be measured
generated, which points in another
whether the oil or gas delivery from
pump on the tool side of the suc-
directly during the drilling process,
direction and is stronger than the
such as how mobile the fluids in the
a newly discovered reservoir will be
tion proboscis sucks and this gen-
and not only after completion of
original one, the atoms will turn in
pores are etc, are the result of clever
worthwhile or not, it is necessary to
erates a certain negative pressure
the borehole, using a special evalu-
the direction of the new magnetic
mathematical/physical methods
know how high the reservoir pres-
against the borehole wall. When
ation system, which is brought into
field, but flip back to their original
of evaluating the measured
sure is. We have developed our Tes-
the pump is shut off, it takes a while
the borehole on a power cable.
position when it is switched off.
values. The engineers
Trak tool for this purpose.
for the pore fluid to flow out of the
This, in fact, costs much more time
All further measurements,
The „echo“, generated by
probably would not
formation and into the proboscis,
and money and furthermore the
the atoms „flipping back“ can be
have thought of it at
name „Mosquito“ for this tool. This
equalizing itself with the reservoir
information gained can no longer
measured. The smaller the pores
all, but that is why we
name appealed first of all because
pressure. The ability of the pore
be used to optimize the path of the
in the rock are, the faster the echo
also have many clever
TesTrak extends a sort of proboscis
fluid to flow can be deduced from
well.
decays, so this provides a method
physicists, mathema-
to measure the reservoir pressure –
the duration of this pressure equal-
of measuring the pore size.
ticians and other
something like a midge biting – with ization process, the longer it lasts,
only accepted by our customers as
Previously we flirted with the
scientists in our
which a sample of the reservoir fluid the more poorly the coveted raw
a constituent part of the drill string,
development
is sucked out.
materials flow (and the lower the
if it does not impede the drilling
flipping back, as the pore size
department.
production from the reservoir will
work too much. This is easier said
is already known it is possible to
sucked out which is investigated,
be).
than done. As long as the suction
conclude from this measurement
but rather the extraction process is
proboscis is occupied with the
whether gas, water or oil is present
observed and evaluated. At the
Trak tool is that for the first time the
58
During this, it is not the fluid
The special feature of our Tes-
59
5
10
Of course, our TesTrak tool is
measure of the number of atoms
The „volume“ of the echo is a
0
15
sampling process, the drill string
20
W HAT D OE S I N TE Q M A N U FAC T U R E ?
–5
How R eli a bly And W ell Do W e Dr ill? (CoPilot)
may not move. And a stationary drill
rement is also of vital importance. The absolute accu-
The majority of oil and gas wells will
same time the drill string is, well …,
horizontally along the basement
string is normally a red flag to our
racy of the pressure measurement must be less than
be between 3 and 6 km deep and
let us say 5 km long. The length
ceiling thought the floor to the elec-
drilling contactor who wants first
0.5 bar (note: 1 bar is about 14 PSI) with an accuracy of
not usually vertical, but often at an
of the drill string is therefore about
trics box in the utilities area.
and foremost to drill and not to
replication of less than 0.1 bar and a resolution of 0.01
angle in the lower section or even
40,000 times greater than its di-
measure. So the measurement must
bar – and all that at absolute pressures of 1 – 2,000 bar!
horizontal. The preceding chapters
ameter.
installed and the cable is ready to
take place quickly, not only because
These requirements are far removed from „normal“
have described in detail how the
thread through. It slides down ver-
of the immense costs of a drilling
measuring tools, the quartz pressure sensor that can
high art of directional drilling func-
length, standing on the rig, appears
tically into the basement almost
system but also because of the pos-
do this cost as much as a small automobile with good
tions.
solid and rigid at first glance. How-
on its own, the lower it goes the
sible risk of the drill string becoming
quality extras!
ever, the drill string at its full length
heavier it is and pulls the rest
stuck in the borehole (differential
ameter is often only 8 ½ inches,
behaves more like a flexible, thin
though with its own weight.
sticking). A period of 5 minutes
repeated three times in succession in the short time
which is just a good 20 cm. Of
wire.
for measurement should not be
available. The good correspondence of the measure-
course, the drillpipe has to have an
Just imagine that you wanted to
The cable can probably simply be
exceeded in any case, that corre-
ments reminds us each time we use it that once again
even smaller diameter so that the
install a satellite dish on your house.
pushed around the bend but then
sponds approximately to the time
our engineers have developed an exceptionally reli-
cuttings can still be carried above
There is even an empty pipe already
we have to play tricks and twist it
taken to screw on another drillpipe
able measuring tool.
ground between the drill string and
there for the cable required. This
around to get it to go further. And if
the borehole wall. A diameter of 5
empty pipe runs vertically down
we turn the cable or apply pressure
inches is usual here, i.e. 127 mm.
from the chimney through several
to it up on the chimney, that cer-
speed of the measurement,
floors until it reaches the basement,
tainly does not mean that down in
the accuracy of the measu-
much if you remember that at the
there it changes direction and runs
the basement, the cable is doing
to continue drilling.
However, in addition to the
60
To be sure that the measurement is correct, it is
A well is not very large; its di-
A diameter of 127 mm is not
A single drillpipe 10 meters in
61
0
The dish on the roof is quickly
But then things get tense.
5
10
15
20
W HAT D OE S I N TE Q M A N U FAC T U R E ?
–5
the same thing.
down in the borehole: the CoPilot.
the extreme conditions in the borehole, where tem-
bouncing on the bottom of the hole instead of turning
peratures and pressures form considerable interfer-
evenly. Other messages can relate to the fact that the
The situation in a well is exactly the same, the drill
At first glance, there is nothing exciting about the
string may be turning calmly and evenly on the surface
CoPilot module. It is a piece of pipe with threaded con-
ence dimensions for which compensation has to be
string is bending too far or the drillpipe is swirling
but that doesn’t mean that 5 kilometers further down
nections. However, on closer inspection the sensation
made at great expense.
around in the hole or banging backwards and for-
in the hole everything is going smoothly. Who knows?
is under the sleeve covering the tool. There, everything
wards.
Perhaps the bit is sticking now and then, tears itself
is stuffed full of sensors and electronics.
continuously and at very high frequency (acceler-
free a moment later and then makes up the missing
ations, forces, pressures and temperatures) and files
CoPilot, as to whether the bit loading applied is actu-
revolutions of the string by jerking and hammering
the torque and bending moments are particularly
the measured values in the memory in the tool. So far,
ally present at the bit, whether the drill head is still cut-
until the game starts again from the beginning. If it
worth mentioning. These are based on so-called
however, all that is nothing special, our competitors’
ting well enough and much, much more. The bending
was like that, the drilling assembly would definitely not
strain gauges. These are small grids of metal which
equipment can manage this too.
moment measurement in the CoPilot tool enables con-
last very long. But – as we said – from the surface nor-
are attached to the CoPilot tool using a well thought
clusions to be drawn about the curvature of the bore-
mally you don’t know what is going on down in the
out plan and connected together electrically. Under
ive quantity of measured values but evaluates and
hole and warns about “kinks” in the borehole path
borehole after damage to or destruction of the drilling
the influence of outer forces, the material of the tool
assesses them on the spot is completely new and has
which can occur e.g. at transitions between different
assembly, it is only possible to find out the cause of the
expands or is compressed. During this the grid rods
no competitor in the marketplace. As long as every-
hardnesses of rock.
problem after the event via a detailed examination of
attached with adhesive either become slightly longer
thing is OK, the CoPilot reports “everything in the
the damage.
and thinner or shorter and thicker. This deformation of
green area”. However, if dangerous disruptions to the
the grid results in an extremely small change in electri-
drilling operation occur, the CoPilot gives the alarm.
clever engineers invented and “underground eye”
cal resistance which can be detected by very sensitive
On a screen in the rig suddenly for example „Warning,
with which we can “see” exactly what is going on deep
electronics. This measuring principle works, even in
Bit Bouncing“ appears. That means that the bit is
Now, I’m sure you have guessed: of course, our
62
The sensors for measuring the load on the bit,
The CoPilot measures a total of 14 sensor channels
The fact that the CoPilot not only stores the mass-
Furthermore, information can be checked with the
0
5
10
15
63
20
W HAT D OE S I N TE Q M A N U FAC T U R E ?
–5
C a n t h e data flow from down hol e
to su r face be op t imi z ed ?
Isn’t it wonderful that we have an evaluation tool avail-
to be installed and removed quickly in a dirty environ-
tunately it only works down to a depth of approxi-
able for practically every influencing dimension of inter-
read them out and evaluate them after the drilling
ment. Finally, every electrical connection contains the
mately 3 km, however, even then only with such long
est that we can install in the drill string? However, there
assembly has been removed. But that is a pity because
risk of a contact fault with the consequence that com-
wave signals that the transmission is just as slow as
is a problem: if Coiled Tubing wells are disregarded,
the whole point of putting the evaluation tools in the
munications could be lost. That is too risky. Moreover, a
with a pulse valve. Well … in that case we might just
the only way the data collected downhole can reach
string is to have the information available during drill-
cable several kilometers long in the drillpipe could tear
as well use a pulser
the surface is via the data pulser of the MWD tool.
ing. Don’t you want to use the swimming trunks in
and block the drill string which can lead to very danger-
which still
The function of a pulser of this kind has already been
your suitcase as soon as you arrive on holiday and not
ous situations in the drilling operation.
works at a
explained in chapter OnTrak.
several days later?
depth of more
the data be transmitted in a similar way?“ you will ask.
than 10 km in advantageous conditions.
OK, so a pulser does work in principle but it is not
You can also store the data in the tools and only
Perhaps you are now asking whether the data can
„But a mobile phone works without a cable! Can’t
particularly quick. This means that far more data is
be transmitted in some “more modern” way than with
being produced than can be transferred to the surface.
such an ordinary pulse valve.
wirelessly by radio out of the borehole or acoustically
Correct, attempts are being made to transmit data
In principle, data
via the drill string.
can also be transmitted
For example, the scientists are developing more and
ters and telephones. Isn’t it possible to install a “tele-
somewhat more
more crafty methods of compressing the data to be
phone line” in the drill string too?
in wells where pressure pulse transmission does not
quickly with acoustic
transferred. In this way the same quantity of data can
work. That is the case if drilling is being undertaken
methods, for ex-
be transported to the surface with fewer pulser move-
hundreds of threaded joints that would be a bit like
using “air” or “foam”, i.e. compressible drilling fluids,
ample, small ham-
ments. That is a bit like packing a suitcase: if you do it
joining together hundreds and hundreds of extension
which cannot pass on pressure waves. The data is then
mers, which strike
right, you can get much more in than if you just stuff
cables to operate a power drill in Wienhausen from a
transmitted through the stone by radio. In itself, an
the drillpipe, but
everything in without taking care.
socket in Celle. Moreover, the drill string must be able
electromagnetic transmission is a fine thing, but unfor-
here too, no one
The situation can be improved to a certain degree.
64
We are interlinked everywhere now with compu-
Well, as the drill string can consist of hundreds and
Electromagnetic transmission is used specifically
65
0
5
10
15
20
W HAT D OE S I N TE Q M A N U FAC T U R E ?
–5
has managed yet to bridge sufficiently long distances.
realized it you knew half her life story from being
sion would be guaranteed, even if it “spoke” somewhat
Additional amplifier stations would have to be installed
forced to listen.
faster.
in the drill string. All in all, this too is not much faster
than pressure pulses. The amplifier stations increase
ning. The unknown woman embodied the principle for
design it. Instead of individual, slow pulses, he allowed
the cost and also the risk of a fault.
solving the problem!
the valve to “flutter” on and off at higher frequencies.
Different high tones now serve as “zeros” and “ones”
So for the time being, even though we are still
It struck our engineer suddenly like a flash of light-
The conventional pressure pulses for data trans-
No sooner said than done, our engineer started to
researching diligently into other solutions, we are still
mission have the quite serious disadvantage that they
which shrill through the drill string, relatively unim-
staying with the “simple” solution of working with the
work in a frequency range in which most of the “noise”
pressed by the background noise, like the striking voice
good old pressure pulses.
is produced during drilling. Not only the pulser pulses
of the woman through the aircraft.
„If it were at least possible to convey pressure
in the frequency range around 3 Hertz, but also the
pulses through the drill string in a more effective way
giant pistons of the mud pump and even the rollers
used instead of two, the efficiency of this system can
than in the past so that the data rate could be in-
cones of the bit generate similar pressure fluctuations
be increased even further.
creased!“, grumbled one of our engineers when he
which rustle through the drill string. Therefore the
was on a long flight overseas and could not sleep. A
voice of the pulser can disappear into the general
few rows behind him, a woman was sitting, who had
noise level in some circumstances until it is incompre-
a particularly noticeable voice which could be distin-
hensible.
guished clearly above the general background noise
from the other passengers. Whatever you did, this
which rises clearly above the other murmurs of its sur-
woman’s voice was constantly present and before you
roundings, then clear and unambiguous data transmis-
66
0
5
Now if even more different tones (frequencies) are
10
Yes, here too, INTEQ sets the tone!
15
If you could fit up the pulser with a „shriller“ voice
67
20
W HAT D OE S I N TE Q M A N U FAC T U R E ?
–5
Chapter 3. 3
Application
and Planning
Software
In the preceding chapters we have
Or another problem: what use is the
in rotary operation, if it is set too
where it is hot and a higher pres-
threaded joints on the drillpipe
learnt that INTEQ develops and
best possible drilling plan for a long
small, the drilling assembly may not
sure prevails, this only produces a
cope? Is the crane hook on the rig
enough to prevent a possible inrush
uses a wide range of drilling and
horizontal drilling path, if the drill
get round the curve properly. The
tiny volume of foam. Here, the soft-
in a position at any time to be able
of gas into the hole at any time? On
evaluation tools. All of these sys-
string cannot be pushed forwards
best possible solution to the prob-
ware helps to find the right settings
to pull the drill string out of the
the other hand, it must not be so
tems are gaining a higher and
but always buckles when weight is
lem is dependent in every individ-
on the surface to produce the best
hole again? How will the string
heavy that it crushes the less stable
higher performance, drill more
applied from the surface?
ual case on the combination of the
possible drilling conditions at the
bend under load and will the com-
rock strata, enabling the expensive
quickly, and save more and more
drilling assembly and the drilling
bottom of the well. Is the light-
plicated components of the drilling
drilling fluid to be lost into under-
drilling costs in this way.
even the best drilling systems can-
conditions but is always found
weight foam in a position to bring
assembly survive these loads? Will
ground cracks. Can the drilling fluid
not replace careful planning of the
quickly and reliably by our applica-
the cuttings with it and discharge it
the drill string turn evenly in the
still do its work if its characteristics
fact is often disregarded that the
entire drilling process. This is why
tion software.
from the hole? Questions of this
conditions in which it is to be used
change at great depth or high tem-
use of the best possible technol-
we have a development depart-
type can also be answered reliably
or is there perhaps a risk of serious
peratures? What pressures do the
ogies is only crowned with success
ment which deals specifically with
drill with foam or compressed air
by the software.
resonances and vibrations which
pumps have to generate anyway to
if the “whole caboodle” is harmo-
the compilation of application and
instead of water? That is not a prob-
could lead to damage and failure?
ensure that sufficient fluid is trans-
nized. For example, drilling more
planning software.
lem in principle, however, you will
to push the string along the entire
Our software will answer these
ported down through the string,
quickly means that much more cut-
discover that although you suck in
planned path of the well? How
questions immediately. In this way
which is several kilometers long,
tings are produced in the hole. If
What tilt angle should you set on
a considerable quantity of air and
large will the friction forces be
any possible problems can be dis-
and back to the surface in the nar-
this is not transported out of the
the directional drilling motor? If it is
some water on the surface at envi-
when we want to rotate the drill
covered and corrected on the com-
row annular gap between the string
hole properly, then the drill string
set to large, the “kick-off” motor will
ronmental pressure and tempera-
string? Will the drive on the rig be
puter even before the drilling work
and the borehole wall? Is the bot-
can be buried and become stuck.
definitely not drill as well as it could
ture, deep below in the borehole,
able to manage it and will the
starts.
tom of the hole cleaned well
However, in this analysis, the
You will have guessed already:
There is plenty to plan, like:
68
Or perhaps: Would you rather
Or maybe: Will it be possible
69
Even: Is the drilling fluid heavy
0
5
10
15
20
W HAT D OE S I N TE Q M A N U FAC T U R E ?
–5
from the bit or is the bit wasting
to the start: our drilling systems en-
energy senselessly by traveling over
sure the rapid and reliable progress
the same lumps of rock again and
of the drilling operation, our evalu-
again and crushing them to fine
ation tools help us to find the best
dust. Our cleverly designed hydrau-
way and our software plans, moni-
lics programs know the answers to
tors and co-ordinates the entire
questions like this and help us to
drilling process.
refine the drilling fluid system.
means minimizing the irritation
In principle, all the programs
And that brings us right back
For the drilling contractor this
used in planning the drilling pro-
whilst simultaneously maximizing
cess can also be used subsequently
the prospects of success for a pro-
„online“ to optimize the drilling
ject.
parameters in situ. For example, if
you compare data measured during
He can rely on INTEQ.
drilling with the figures calculated
in advance, it is possible to detect
problems with the discharge of the
debris at an early stage.
70
3,600
1,000 bar
enough by the jet of fluid emerging
1
75
Hz
0
5
10
15
71
20
–5
–5
0
0
5
[
4
And finally
]
5
10
10
15
15
20
20
A N D F I NA L LY
–5
All’s well –
that ends well.
0
That concludes our tour of the INTEQ Drilling Tech-
few new insights into our company’s products to begin
Departments will be only too pleased to provide you
nology Exhibition. Of course we could not show you
with. We can be really proud of producing unique and
with the information you need.
all the drilling and evaluation tools our company offers
reliable high-tech products for a market with unprece-
and sells. It is not possible, simply because technical
dentedly extreme requirements. The insides of many
have appeared without the unselfish assistance of
progress moves forward and we have to bring new
of our drilling and evaluation systems look more like
my colleagues. I would like to offer special thanks to
products faster and faster into the marketplace to keep
spares for space satellites than components of a „drill-
Detlef Hahn, Matthias Meister, Uli Hahne, Hartmut
our leading position in the tough business which is
ing machine“! And new developments continue to
Grünhagen, Roland May, Gerald Heisig and Brian Riley,
drilling for oil. Regardless of when the book appears, it
drive us forwards. No doubt a new edition will be pro-
who have enriched the project with their constructive
will always already be a little out of date. A complete
duced one day which will inform you about the most
criticism and technical knowledge.
description of all our services and products would also
recent achievements in deep-hole drilling.
soon make this little book swell into a thick tome that
no one would want to read anymore.
product functions which you are working on. Your col-
leagues in the Engineering and Technical Services
For today, we hope that this book has given you a
Until then, just ask if you don’t know quite how the
With regard to colleagues: this book would never
5
10
Thank you very much!
Matthias Reich
15
74
75
20
Baker Petrolite
CENTRILIFT
Baker Atlas
Baker Hughes INTEQ
Baker Hughes INTEQ
Hughes Christensen
Baker Atlas
Baker Petrolite
of Baker Hughes
Baker Oil ToolsThe Divisions Hughes
Baker Atlas
Christensen
Baker Atlas
Baker Hughes INTEQ
Baker Oil Tools
Baker Petrolite
Baker Oil Tools
Baker Petrolite
Baker Hughes Drilling Fluids
Baker Petrolite
Baker Atlas
CENTRILIFT
Baker Hughes Drilling Fluids
Bohrtechnik U engl_RZ 2
Baker Hughes Drilling Fluids
Hughes Christensen
01.12.2004 14:18:28 Uhr
T H E FA S C I N AT I N G WO R L D O F D R I L L I N G T E C H N O L O G Y
0
5
10
BAKER
HUGHES
20
Over 850 employees are based at the Ger-
in Celle
man branch office in Celle. Eighty percent
T H E FA S C I N AT I N G WOR L D O F DR I L L I N G T E C H N O L O G Y
Products from Baker Hughes and their Functions
15
Baker Hughes around the world and
of those work for the INTEQ division,
Baker Hughes is a world-leading tech-
where drilling systems are developed and
nological corporate group in the oil-
drilling systems and diamond bits are
field service industry. Based in Houston,
produced and marketed internationally.
Texas, the company has a presence in over
Our sales region incorporates central and
60 countries and employs around 27,000
eastern Europe, Russia and central Asia.
people of nearly 100 nationalities. With
Baker Hughes also offers highly specia-
seven divisions linked to its product lines
lized services for drilling rigs (particu-
– Baker Hughes INTEQ, Baker Oil Tool,
larly for directional drilling). Almost 30
Hughes Christensen, Baker Atlas, Baker
percent of our staff members in Celle are
Petrolite, Centrilift, and Baker Hughes
engineers.
Bohrtechnik U engl_RZ 1
Baker Hughes, Christensenstr. 1, D-29229 Celle
www.bakerhughes.com
Tel. +49 (0) 51 41 203-0, Fax +49 (0) 51 41 203-296
www.bakerhughes.de
BAKER HUGHES
Drilling Fluids – Baker Hughes carries out
research and development and works for
all mineral oil and natural gas producing
organizations around the globe.
25
01.12.2004 14:18:28 Uhr