COURSE
ADVANCED DRILLING ENGINEERING
Developed and Presented by
Professor Samuel O. Osisanya, Ph.D.; P. E.
Professor & SPE Distinguished Lecturer 2011-2012
Mewbourne School of Petroleum & Geological Engineering
The University of Oklahoma, Norman, USA
1
© Copyright 2013
Day 1 – Fundamentals Concepts Used
in Drilling Engineering and Rig
Components and Rig Operations
2
1
FundamentalConcepts Used in Drilling
 Petroleum Geology
– Rock types, rock properties and their composition
 Temperature
 Pressure
– Both temperature and pressure are forms of
energy
3
Rocks Types
 Rock types of interest to PEs are sedimentary in
nature and can be divided into three groups
– Fragmental or clastic
– Chemical or precipitated
– Biological
 Fragmental rocks are of sedimentary origin - shale &
sandstone
 Chemical rocks are also of sedimentary origin; they
are formed during quiescent time - limestone,
dolomite, chalks
 Biological rocks are from dead plants and animals:
coal, corals
4
2
Formation of Clastic Rocks
There are six processes for clastic sedimentary
rock formation.
●
Erosion. Existing rocks are broken down.
●
Transport. Wind or water move the rock fragments.
●
Deposition. Rock fragments are laid down in beds.
●
Compaction. Burial decreases the sediment volume.
●
Cementation. Minerals grow in the spaces between
grains.
●
Diagenesis. Chemical changes to fragments to form rock.
Engineers Training for Drilling Can Cheer Daily!
5
Relative Abundance of
Sedimentary Rocks
● Shale is the dominant
sedimentary rock comprising
75% of the total.
● Sandstones and
conglomerates account for
11% of the total worldwide.
● Limestones and dolomites
comprise 13%
● All others together make up
about 1% (evaporites, coals)
6
3
Drilling Shales
●
Reactive shale minerals hydrate and
destabilize the wellbore
●
Fractured or stressed shales can be very
unstable
●
Competent shales are suitable for setting
casing
●
Shales cause 90% of all geological hole
problems! (wellbore instability)
7
Drilling Limestone
●
Fractured and vugular limestones may
cause total losses and stuck pipe
●
Bentonite based mud systems may
flocculate with drilled limestone
●
Chert inclusions can destroy most bits
●
Unfractured limestone can make a good
casing point
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4
Drilling Coal
● Coal is brittle and is often fractured. If not
already naturally fractured, drilling stress may
fracture it.
● Mechanical stuck pipe due to blocks of coal
falling in
● Gas may be present
● Overgauged hole and ledges
● Total losses in fractured coal
● Can ignite if drilled with air
9
Drilling Salts
● Under pressure and temperature salt is a
plastic material and will flow or extrude into the
hole
● Very high pressure kicks possible in or just below the salt
● Muds and cement slurries must be designed for the
particular salts present
● Casing must be designed to withstand mobile formation
● Hole size may close behind the bit or bottom hole
assembly preventing pulling the drillstring, may cause
torque and drag and ultimately lead to stuck pipe
10
5
Rock Properties Essential to Drilling
 Porosity, () = Vp/Vb: total or effective; primary or secondary
– Porosity varies between 3-4% - 37% in most reservoirs
(0% - 45.6% theoretically); depends on arrangement and
shape of the rock grains.
 Permeability = K = QµL/AP: conductance of fluids in rock;
lost circulation occurs in extremely permeable rock; high mud
filtrates in high permeability rocks; and can lead to stuck pipe
 Fluid saturation & fluid types
– Sg = Vg/Vp), So = Vo/Vp, Sw =Vw/Vp; Vg + Vo + Vw = Vp
– Fluid type may contaminate the drilling fluid
11
Why Rock Properties?
A knowledge of rock properties and their
compositions helps drilling engineer in
solving many complex drilling problems
● Low rate of penetration
● Lost circulation,
● Swelling shales,
● Abnormal pressures, etc.
12
6
Principal Stresses in Normal Rock
Principal stresses
are usually
compressive
but can be tensile.
13
Highest Principal Stress, 1
1 = stress due to overburden (normal area); the
overburden is measured by integrating a
Density Log to calculate the total weight of the
rocks, which is divided by TVD.
1 might not be vertical in;
● Tectonically active areas
● Close to salt diapirs
● If very deep
● Close to faults
 b  g 1      fl
  o e  KD
s
 ob g  [  g   g   fl o e  KD ]dD
D
Dw
o
 ob g  [ swdD  g  [ g   g   fl o e  KD ]dD
o
D
Dw
14
7
Least Principal Stress, 3
●
3 is normally horizontal.
●
The Eaton Equation can be used
to calculate 3 if Poisson’s ratio
() is known.
●
A Leakoff Test will give a direct
indication of 3 (equals fracture
closure pressure)
15
Intermediate Principal Stress, 2
●
2 is normally horizontal.
●
2  1.1 x 3 (valid for the North
Sea). This is only true in tectonically
relaxed areas
●
Horizontal stresses can be
estimated by deduction from offset
well instability (4 arm caliper log) or
regional trends.
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8
Temperature and Pressure
● Pressure & Temperature - forms of stored energy
– Affects the physical and chemical properties of the
rock and the fluids it contained
● Temperature and Temperature Gradient
– Temperature increases with depth; hence heat flows
from center of the earth by conduction
– Some rocks are better conductors than others
– Temperature is measured by thermometers
● In general, TD = Ts + G x TVD (true vertical depth)
– Ts = f(latitude) - 70oF (Gulf Coast) & 10oF (Alaska)
– Normal temperature gradient, G = 1.6oF/100-ft 17
Importance of Downhole Temperature Data
● Beneficial to fluid recovery - reduces µ
● However, not beneficial to drilling operations
– Higher temperature has adverse effects on drilling
hardware and materials
– Mud treating chemicals and clays become ineffective
or unstable at high temperature; causes cement
thickening
● In general, below 15,000-ft, many problems are
encountered while drilling due to high pressure and
temperature; and drilling costs become very high.
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9
Uses of Temperature Data
● To locate hole enlargements in shale sections
● To determine the top of cement fill-ups
● To locate thief zones that cause loss circulation
● To locate gas bearing zones - gas expansion
causes cooling
● To locate casing leaks or to detect gas leaks
● To aid correlation of strata that have different specific
heats and thermal conductivity
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Typical temperature log
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10
Pressure
●
Major sources are earthquakes
– Compression and tension effects on rocks
●
●
Minor sources are tides, seismic sea
waves, chemical reactions (radioactive
decay & biochemical)
Units of pressure are
– US : psig, psia; SI: N/m2 or Pa; 1 N/m2 = 1 Pa
– Another common unit is atmosphere
• 1 atmosphere = 14.7 psia
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Types of Pressure
• Pressure can be normal, abnormal, subnormal
 All pressures (except abnormal) can be measured
with self-contained pressure bombs
• Static or Circulation
 Static is due to fluid at rest
 Circulation includes frictional pressure loss due to
viscosity of the fluid
• Total overburden pressure (Poverburden)
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11
Types of Pressure
• Fracture pressure/fracture gradient
This is a pressure at which a rock fails
Fp < overburden
Uncontrolled breakdown of a rock leads to
loss circulation  a kick  blowout
• Effective stress = confining pressure - pore
pressure. If confining pressure = overburden
stress; then effective = overburden - Pp
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Fundamental Pressure Equations
For liquids - P = 0.433xHxS = 0.052xHxG (psi)
– H is ft, S = specific gravity, G is in lbm/gal
● For gases - P2 = P1xe(0.01875xGxH/ZavgxTavg) (psi)
– G is gas gravity, H is ft,Tavg is in oR
● Rule of thumb equation for gas
– P2 = P1 + 0.25 x (P1/100)x(h/100) (psi)
● Total overburden pressure
– P = 0.433xHxSb = 0.433xH[(1-)Sm +  xSf)] (psi)
– H is ft, Sb, Sm,Sf are bulk, matrix, & the fluid specific
gravity
●
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12
Importance of Pressure
● Plays a vital role in the life of a well from drilling
time to abandonment
● Improper control of pressure can lead to a kick,
blowout, loss of equipment, pollution, and loss
of life
● A knowledge of pressure decline is essential to
production and reservoir engineers.
● Pressure measurements are indispensable
petroleum engineering tool
25
Normal Pore Pressure
●
Assume all formations are
permeable vertically.
●
Fluid in pores becomes more
saline with depth so gradient
increases.
●
Normal pore pressure at any
depth = depth x average fluid
gradient above.
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13
Abnormal Pore Pressure
●
Pore pressure can be
different to the normal
pressure for the depth.
●
Two conditions are both
necessary for the
development of abnormal
pressure
1.
Impermeable barrier above.
2.
Mechanism causing pressure
change.
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Normal Pressure vs. Abnormal Pressure
Question: Normal pore pressure gradient = 0.465 psi/ft

What is the pressure at 5500-ft?

Is the pressure of 2950 psi at 5500-ft normal or
abnormal in an offset well?
Solution:

Normal pressure = 5500 x 0.465 = 2558 psi.

Pressure at 5,500’ in offset well = 2,950 psi. Since
this pressure is higher than 2558 psi in the other
well, then the pressure of 2950 psi is abnormal.
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14
Worked Example 1
Question: A protective string of casing was set and cemented
at the depth of 3,000 ft. A blowout preventer (BOP) was
mounted on top of the casing to seal the annular space
between the casing and the drill pipe. The drilling fluid at this
time weighs 9.2 lbm/gal (ppg). Assuming that the formation
can only hold 70% of the theoretical overburden pressure,
how much pressure can be held against the well by the
(BOP)?
Solution: Assumed bottom hole breakdown pressure at 3,000 ft
= (0.70)(1 psi/ft)(3,000 ft)
= 2,100 psi
Hydrostatic pressure = (0.052)(9.2 lbm/gal)(3,000 ft) = 1,435 psi
Pressure that can be held by BOP = 2,100 psi - 1,435 psi
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= 665 psi.
Worked Example 2
Question: A formation is to be hydraulically fractured at the
depth of 9,000 ft. The fracturing fluid has a specific gravity of
0.85. If the formation breaks down at 80% of the theoretical
overburden pressure, what pump pressure will be required
for the breakdown?
Solution: Expected formation breakdown pressure
= (0.80)(1 psi/ft)(9,000 ft)
= 7,200 psi
Hydrostatic pressure of the fracturing fluid
= (0.433 psi/ft) (0.85) (9,000 ft)
= 3,312 psi
Required pump pressure = expected formation breakdown
pressure - hydrostatic pressure = 7,200 psi - 3,312 psi
= 3,888 psi
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15
Worked Example 3
Question: A formation has a pressure of 3720 psi at
8,000 ft. The operator desires to have a safety
allowance of 600 psi opposite the formation. What is
the required density of the drilling mud?
Solution: Rearranging the equation P = 0.052 x G x h,
we have, G
= P/(0.052 x h) (lbm/gal)
P = formation pressure + the safety allowance
= 3720 + 600 = 4320 psi
G = 4320/(0.052 x 8,000) = 10.4 lbm/gal
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Rig Components and Rig Operations
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16
Outline
 Drilling Rigs
 Rig Components
 Power system
 Hoisting system
 Fluid-circulating system
 Rotary system
 Well control system
 Well monitoring system
 Rig Safety, Environmental Concerns; & Waste
Management
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Objectives of Drilling Operations
1. Minimize the total well cost (i.e.
maximize return on investment)
2. Drill a useable hole (minimize
formation damage)
3. Drill well in a safe and
environmentally sound manner
34
17
Classifications of Rigs Based on Location

1.
2.
3.
In general, there are three
locations: onshore, swamp or
offshore/deepwater/ultra
deepwater
Onshore: mast or mobile
(generally of the cantilever
type)
Swamp: tender barge or jackup (they are bottom-supported)
Offshore: tender barge, jack-up,
semi-submersible, drill ship
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Land Rigs - (Heavy Land Rig)



Capable of
drilling deeper
than 10,000-ft
Typical derrick
load is greater
than 1,000,000
lbf
BOP rating
greater than
10,000 psi
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18
Land Rigs – Helicopter Portable
 Breaks down into small packages for
moving (6000 lbf max)
 Can deploy in locations not otherwise
useable without very high cost (jungle,
mountain tops, inaccessible locations)
37
Marine Rigs – Bottom
Supported – Platform



Self contained rig installed on platform
Once drilling finished, rig can be removed or
replaced with small workover rig
Can be “tender supported” like the one on the left
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19
Offshore Rig - Jack up

Usually 3 legs which
stand on the seabed
(bottom supported)

Hull is lowered and legs
raised for rig moves

Can drill in shallow
waters (to 300-ft)

BOP’s are below the
derrick cantilever

Accommodation for up to
100 and very expensive
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Offshore Rig - Semi-Submersible




Rig towed on to
location, then either
anchors or uses
dynamic positioning
Can move off location
fast if there are
problems.
Usually uses BOP’s
located at the seabed.
Accommodation for up
to 100. High cost
40
20
A typical semi-submersible drilling rig
41
Deepwater Offshore Rig – Drillship



Ship shaped hull,
usually self-propelled
for rig moves
Often uses Dynamic
Positioning but may be
anchored
High storage capacity;
1 or 2 wells without resupply, and very
expensive
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21
Offshore Rig Selection
• Many designs criteria are used in selecting the proper
marine rig. Major criteria are as follows:







Water depth rating (first evaluation tool)
Derrick and substructure capacity
Physical rig size and weight (MAINTENANCE HISTORY)
Deck load capacity
Stability in rough weather (wind)
Duration of drilling program
Rig rating features such as horsepower, pipe handling and
mud mixing capabilities
 Exploratory versus development drilling
 Availability and cost.
• Rig mobilization costs must be considered when selecting
marine rigs and this is a function of number of wells to be drilled.
43
Drilling Rigs
● Another rig classification scheme is based on
ownership
 Company-owned and operated (few)
 Contractor-owned and operated (majority)
 Partnership-owned
 Company-owned but contractor operated
● Rig contracts: daily, turnkey, incentive,
footage and IPM (Integrated Project
Management)
44
22
A Typical Drilling Organization
45
Drilling Team
 Drilling Contractor
 Tool pusher, drillers, derrickman, roughnecks
 Other specialists - crane operator, mechanics,
electricians, roustabouts, caterer
 Operator’s Representatives
 Company man, drilling engineers, geologists, and
consultants
 Service Companies
 Cementer, loggers (mud & wireline), mud engineer,
directional engineer
46
23
Rotary Drilling Process
1. In rotary drilling, the bit is
turned by rotating the
entire drill string, using a
rotary table at the surface
2. The entire downward
force is applied to the bit
by using sections of
heavy thick-walled pipe
called drill collars, in the
drill string above the bit.
47
Offshore Rig Selection
● Many designs criteria are used in selecting the proper
marine rig. Major criteria are as follows:







Water depth rating (first evaluation tool)
Derrick and substructure capacity
Physical rig size and weight (MAINTENANCE HISTORY)
Deck load capacity
Stability in rough weather (wind)
Duration of drilling program
Rig rating features such as horsepower, pipe handling and mud
mixing capabilities
 Exploratory versus development drilling
 Availability and cost.
• Rig mobilization costs must be considered when selecting marine
rigs and this is a function of number of wells to be drilled.
48
24
Basic Rig Components and Operations
 All rotary rigs have the same basic drilling
equipment, with the following major
components or systems
1. Power system
2. Hoisting system
3. Fluid-circulating system
4. Rotary system
5. Well control system
6. Well monitoring system
49
Rig Power System
● Most rig power is consumed by the hoisting and fluid
circulation systems. Fortunately, both systems are not used at
the same time.
● Power requirements: 1,000 - 3,000 HP (horse power)
● Types of power prime movers: IC diesel engine & dieselelectric
● Mechanical HP requirement for prime movers must be
modified for harsh temperature environment & altitude
● Power-system performance characterized by output HP,
torque, fuel consumption, and efficiency
● Most power transmission is by alternating current (AC)-silicon
controlled rectifier (SCR) combined with motors – low cost,
light weight, less maintenance, and long life
50
25
Rig Power System
Typical diesel-electric power system
51
Heating Values of Various Fuels
Fuel
Type
Diesel
Density
(lbm/gal)
Heating Value
(Btu/lbm)
7.2
19,000
Gasoline
6.6
20,000
Butane
4.7
21,000
Methane
---
24,000
52
26
Hoisting System
 Function: To provide a means of lowering and
raising equipment into or out of the hole
 Principal components
 Derrick & substructure
 Block & tackle pulley arrangements and drill line
 Drawworks
 Major routine operations
 Making connection
 Making a trip
 Slip and cut program
53
Schematic of Block and Tackle
1. Comprises of crown block,
traveling block, and drilling
line
2. Provides a mechanical
advantage, which permits
easier handling of large
loads
3. Generally mechanical
advantage is less than n
(i.e. less than 100%) due
to friction
4. As n increases,
mechanical advantage
decreases tremendously.
54
27
Average Efficiency Factors for
Block and Tackle System
Number of Lines
(n)
6
8
10
12
14
Efficiency
(E)
0.874
0.841
0.810
0.770
0.740
55
Drilling Line
 Subjected to severe service during normal tripping
operation
 Failure of the line can results in injury to personnel,
damage to the rig, and loss of the drilling string
 Hence, drilling line tension < yield strength of the line
 Severe wear occurs at pickup points on
travelling/crown blocks and the drawworks
 Severe points must be changed regularly by
following what is called SLIP & CUT PROGRAM
(similar to oil change for your car)
56
28
Slip and Cut Program
 Slip and Cut procedure:




Stop drilling and Loose the dead line at the anchor
Place a few feet of new line in service from the storage reel
Remove the some worn out line from the drawworks
Cut off a section of the line from the end
 Slip-cut program is evaluated using the ton-mile method
 Based on the assumption that a line will safely perform so
much work (ton-mile)
 A line has rendered 1 ton-mile when the traveling block has
moved 2,000 lbf a distance of 1 mile
 Must keep a record of ton-mile in order to have a satisfactory
slip & cut
 Ton-miles vary with drilling conditions, hence use field
experience (SHOW THE PICTURES)
57
Drawworks
● The drawworks is the control center of the rig and it
houses the drum which spools the drilling line
● Principal parts are: drum, brakes, the transmission,
and the catheads
● Its design depends on prime mover type and power
transmission type
● Rated by horse power & depth
 Must specify the size of drill pipe with the rating
 Drawworks HP = (W x Vh)/(33000 x E); W is lbf and
Vh is in ft/min, E is hooks to drawworks efficiency
58
29
Drawworks – Rig Control Center
59
Rig Fluid Circulating System
 Function is to remove rock
cuttings out of the hole as
drilling progresses
 Principal components are
 Pumps
 Pits/tanks
 Mixing devices
 Contaminants removal
equipment (solid control
devices), and
 Flow conduits
60
30
Rig Fluid Circulating System
61
Mud Pumps
● The function of mud pumps is to circulate fluid at desired
pressures and flow rates
● Mud pumps are generally of the reciprocating types: two
types - double-acting (duplex) and single-acting triplex
● Pumps are denoted by the stroke, bore and rod diameters
(for duplex only)
● Commonly rated by horse power (HP), max. pressure and
maximum rate
● Two to three pumps are generally installed on a rig
 One as a standby; two used when drilling surface holes; and
one used at deeper depth
● Overall pump efficiency = mechanical efficiency x
volumetric efficiency (Em x Ev)
62
31
Double-Acting Duplex Pump
● The function of mud pumps is to circulate fluid at desired pressures and
flow rates
● Mud pumps are generally of the reciprocating types: two types - doubleacting (duplex) and single-acting triplex
 Has two pistons and it sucks and
discharges on every stroke
 Pump factor, Fp = pump displacement
per complete cycle (or stroke)
 Fp = (/4)(2)(Ls)[(2(DL2)) - Dr2)]Ev
 Ev = pump volumetric efficiency
 Hydraulic pump HP =(P)(Q)/1714
 p = diff. pressure, psi (Pout - Pinlet)
 Q = flow rate, gal/min
63
Single-Acting Triplex Pump
 Has 3 pistons and it sucks and
discharges on every two strokes
 Pump factor, Fp = pump displacement
per complete cycle (or stroke)
 Fp = (/4)(3)(Ls)(DL2)Ev
 DL = liner diameter
 Ls = stroke length
 Ev = pump volumetric efficiency
 Note: there is no Dr = rod diameter
 This pump is light, more compact,
cheaper to operate and very useful
offshore where space is limited
64
32
Mud Pits or Mud Tanks
 Mud pits or tanks are made of steel to satisfy
environmental containment
 Three basic types of mud tanks: settling, suction, and
reserve
 Settling: allows time for setting of cuttings &
release of entrained gas
 Suction: the pump sucks good fluid from it
 Reserve: to contain contaminated fluid, cuttings,
and any produced formation fluid
 All tanks are equipped with motor-driven agitators
(mixers)
65
Contaminants Removal Equipment
● Shale shaker - a vibrating screen that removes
coarse rock cuttings/caving such as shales
● Desander - remove sand and prevent abrasion
● Desilter - removes very fine particles and silt
● Hydrocyclone/decanting centrifuge - removes finely
grounded solids
● Mud cleaner - a combination of a hydrocyclone and
a shaker screen, and use only for moderately highdensity fluid
● Degasser - removes entrained gas from the fluid
66
33
Conventional Rig Rotary System
● Rig rotary system includes all the
equipment used to achieve bit
rotation. Can be conventional or
modern type
● Conventional rotary system is
made up of - swivel, kelly/kelly
bushing, rotary drive, rotary
table, and the drillstring (i.e. drill
pipe and drill collars)
● Modern rotary system is TOP
DRIVE, also called power swivel
67
Conventional Rig
Rotary System
Kelly
Kelly
bushing
Rotary table
68
34
Rig Rotary System – Top Drive (Power
Swivel)
 Modern rotary system is TOP DRIVE,
also called power swivel. In this
system the regular swivel, kelly, and
kelly bushing are entirely eliminated
 Has built-in tongs to make and
breakout pipes
 Uses a hydraulic motor to achieve
rotation
 Safer & easier for crew members
to handle the drill pipe
 Saves time as connections are
made very fast and safer. The
crew uses the unit’s built-in tongs.
69
Tubular Specifications
 All tubular (drill pipe, drill collar, casing,
and tubing) are specified by the
following:
 Range (length): 3 ranges - R1 (18 - 22 ft,
now obsolete), R2 (27 - 30 ft), R3 >30 ft]
 Weight per foot
 Outside diameter, OD
 Steel grade (D, E, G [most common], & S135)
 Essentials of tubular
 Tally - each joint must be measured
carefully and recorded, Also, capacity and
displacement volumes must be known
 Pipe capacity = /4xd2; Displacement
capacity =  /4x(d12 - d2)
70
35
Drill Pipes and Drill Collars
 Drill pipes
 Transmit rotational power to the bit
 Transmit drilling fluid to the bit
 Drill collars
 Provide weight on bit
 Prevent buckling of the drill string
 Provide pendulum effects to cause the
bit to drill a more nearly vertical hole
 Support and stabilize the bit to drill new
hole aligned with the already drilled hole
 Drill collars can be round (most),
spiral, or square
 Spiral used in small diameter holes or
deviated wells to prevent or reduce
differential pipe sticking
 Square used in straight hole (vertical)
drilling
Drill pipe
Drill collar
71
Worked Example 4
Question: A drillstring is composed of 7,000 ft of 5-in., 19.5-lbf/ft drill pipe and 500 ft of 8in. OD by 2.75-in. ID drill collars when drilling a 9.875-in. borehole. Assuming that the
borehole remains in gauge, compute the number of pump cycles required to circulate
mud from the surface to the bit and from the bottom of the hole to the surface if the pump
factor is 0.1781 bbl/cycle. ID of 5-in 19.5 lbf/ft drill pipe = 4.276-in
For field units of feet and barrels,
Solution: Ap is calculated as follows:
 gal   bbl   12 in   d 2 


 bbl / ft


Ap   d 2  in 2 

 231 in 3   42 gal   ft   1,029.4 
4 




4.276 2  0.01776 bbl / ft
Thus, the capacity of the drill pipe is
1,029.4
The capacity of the drill collar is
2.752  0.00735 bbl / ft
1,029.4
The number of pump cycles required to circulate new
0.01776 7,000   0.00735 500  bbl  719 cycles
mud to the bit is given by
0.1781 bbl / cycle
9.875 2  52
Similarly, the annular capacity outside the drill pipe is given by
The annular capacity outside the drill collars is
1,029.4
 0.0704 bbl / ft
9.875 2  82  0.0326 bbl / ft
1,029.4
The pump cycles required to circulate mud from the bottom of the hole to the surface is given by
0.0704 7,000   0.0326 500  bbl  2,858 cycles
0.1781 bbl / cycle
72
36
Well Control System
 One of the most important system on the rig. Its functions are:
 To detect a kick and To close the well on surface
 To circulate well under pressure & increase fluid density at the
same time
 To move pipe under pressure
 To divert flow from the rig
 Kick is the uncontrolled flow of formation fluid and occurs when
hydrostatic pressure (PH) is less than the formation pressure (Pf)
 If the well system fails, BLOWOUT occurs - this is perhaps the
worst disaster while drilling
 Effects of blowouts are: loss of life, loss of equipment, loss of the
well, loss of natural resources, and damage to the environment
73
Kick Detection During Drilling Operation
 Kick detection while drilling
usually achieved by use of a
pit volume indicator or mud
flow indicator.
 Both devices can detect an
increase in the flow of mud
returning from the well over
that which is being circulated
by the pump.
 Mud flow indicator can detect
a kick more quickly. Used in
conjunction with pump
strokes.
74
37
Blowout Preventers
 These are special pack-off devices used to stop
fluid flow from a well. A multiple of the pack-of
devices is called BOP stack. Stack arrangement
f (formation pressure & operator’s preference)
 Objectives of BOP
 Stops flow from the annulus with drill pipe in hole
 To determine flow from the well
 To allow pipe movement under pressure
 To allow fluid circulation
75
Blowout Preventers
 Types of BOP - Ram and Annular preventers
 Three types of ram: pipe; blind; and shear
 Pipe closes against the drill pipe
 Blind closes the well when there is no drill pipe in hole
 Shear, is a special blind ram as it shears the drill pipe
 Used only when all pipe and annular preventers have failed
 Annular preventer, also called bag preventer uses a ring of
synthetic rubber packing to close against the drill pipe
 BOP Working Pressures
 2,000; 3,000; 5000: & 10,000 psi
76
38
Components of Well Control System
 Mud flow indicator - detects a kick more quickly, sees the
kick first
 Pit volume indicator - indicates the active pit volume and
presets at high & low levels; an alarm turns a light or a horn
on when the levels are below or above set levels
 Gain in pit volume = kick volume !!!
 Hole fill-up indicator - used while tripping to measure
accurately the fluid required to fill the hole
 Trip tanks - usually very small (10 - 15 bbl capacity) and
provide the best way to monitor hole fill-up volumes
 When the trip tanks are not available, use pump strokes
 Never use active tanks as hole fill-up volume indicator
77
Typical Arrangements of Blowout Preventers
 The arrangement of the BOP stack
varies considerably. The arrangement
used depends on the magnitude of
formation pressure in a particular area
and on the type of well control
procedures used by the operating
company.
 API presents several recommended
arrangements of BOP stacks. This figure
shows typical arrangements for 10K and
15-Kips working pressure service
 A = annular preventer, R = ram
preventer, and S = drilling spool.
The arrangement is defined starting at the casing head and proceeding up to the bell
nipple. Thus, arrangement RSRRA denotes the use of a BOP stack with a ram preventer,
attached to the casing head, a drilling spool above the ram preventer, two ram preventers
in series above the drilling spool and annular preventer above the ram preventer
78
39
Remote Control Panel for Operating Blowout Preventers
 The control panel for
operating the BOP stack
usually is placed on the
derrick floor for easy access
by the driller.
 The controls are marked (and
should be marked) clearly and
identifiably with the BOP
stack arrangement used.
 In general, the control panel
is located away from the rig
floor.
79
Well Monitoring Systems
 A well must be monitored for safety, high efficiency,
and to detect drilling problem
 Different devices are used to achieve these objectives
 Parameter
Device
Measured
Used
 Depth
Geolograph
 ROP
Geolograph (by deduction)
 Hook load
Weight indicator
 Rotary speed
Tachometer on weight indicator
80
40
Well Monitoring Systems
Parameter
Device
Measured
Used
 Torque
Torque indicator
 Pump pressure
Pressure gauge on stand pipe
 Flow rate
Stroke counter
 Fluid density
Mud balance
 Mud temp.
Flow line thermometer
 Pit level
Pit volume indicator
Note: These monitoring devices have now been
computerized on new rigs
81
Well Monitoring Systems
This figure shows the instrumentation for knowing the
hook load (weight indicator), rotary speed, and torque
82
41
Typical Mechanical Drilling Log - Geolograph Chart
83
Types Of Offset Data Geolograph
Chart
42
Mud Logging Report
• Typical responses from gas
in mud. Note that the
liberated response can be
largely influenced by the
penetration rate.
85
Measurement While Drilling
1. For subsurface well monitoring
and data telemetry
2. Uses a mud pulsar installed in
the drill string
3. Gives hole direction (azimuth),
and inclination (deviation
angle)
4. It can be combined with
logging while drilling (LWD)
which refers to wireline quality
formation measurements while
drilling (diagnostics, acoustic
and electrical)
86
43
Geosteering Tool
1. Geosteering is the interactive,
geological placement of a precise,
high angle well path within a
formation.
2. Geo-steering (very recent)
• Combines the features of MWD
and LWD
• Useful while drilling horizontal or
multilateral wells
Optional Dump Valve
PowerPak
PDM
0-3 deg (surface) adjustable
bent housing
Near Bit Sensor Sub
INCL
8.6 ft
This figure is another
typical geosteering
BHA layout. Clearly,
the RAB, GR, and
the inclinometer are
all below 10-ft from
the bit.
Gamma Ray
7.9 ft
Arc Resistivity
3.5 ft
0.75 or 1.25 deg
fixed Bend
Near bit Stabilizer
87
Safety Provisions on the Rig
 Rig equipment are designed to prevent accidents
 Handrails on walkways & stairways
 Guards on all moving machinery
 Pressure relief devices on mud lines & pumps
 Safety clothing - very important
 No loose or floppy dresses
 Hard hat must be worn to protect the head
 Steel-toe shoes must be worn to protect the feet
 Safety goggles to prevent eye injuries
88
44
Safety Provisions on the Rig
 Safety meetings
―Must be conducted often to discuss
procedures
―Must provide manuals for new employees
―Must conduct regular drills
 Special conditions
―Drilling in H2S environment needs special
precautions
89
Environmental Concerns
●
In General:
● Drilling Wastes are Non-Hazardous
– (NOW – Non-hazardous Oilfield Wastes)
● Drilling Fluid Additive Chemicals can be Hazardous
– Toxic, Reactive, Ignitable
90
45
Environmental Concerns
●
Laws - Legislature
●
Rules - Judiciary
●
Regulations – Bureaucrats: determine
what is environmentally acceptable!
91
Environmental Concerns
●
Health and Safety
– Potentially Hazardous Chemicals
●
Caustics (reactive)
●
Acids (reactive)
●
Oils (flammable)
●
Powders (inhalation)
●
Liquids (skin problems)
92
46
Environmental Concerns
●
●
●
●
●
●
●
●
Discharge Limitations in US Offshore
Oil Base Mud - prohibited
Generic Muds - subject to toxicity limit, 30,000 ppm
Additives - approved lists
Bioassays - required, end of well
Free Oil - no discharge based on static sheen test
Barite - 1 mg/kg Mercury, 1-3 mg/kg Cadmium
Cuttings Oil - no diesel discharge, no free oil
Other - no halogenated phenols, chromates,
minimum use of surfactants, dispersants, and
detergents
93
Waste Management
● In General
● Drilling Wastes are Classified as NonHazardous
– (NOW – Non-hazardous Oilfield Wastes)
● The Problems with NOW are Oil and
Grease, Chlorides, and Heavy Metals
● Drilling can Generate Large Volumes of NOW
– Primarily Cuttings and Excess Mud
94
47
Waste Management
Types of Waste Generated
● Drilling Fluids
● Drill Cuttings
● Rig wash
● Pipe Scale
● Pit Sludges
● Fuel and Lubricants
95
Waste Management
Types of Waste Generated
● Service Company Wastes
● Hydraulic Fluids
● Waste Solvents
● Caustic or Acid Cleaners
● Laboratory Wastes
● Sanitary Wastes
● Used Frac Fluids
● Painting Wastes
● Vacuum Truck Rinsate
● Used Lube Oil
● Waste Compressor Oil
and Filters
● Pesticide Wastes
96
48