The SVALEX 2014 pre-course assignment
To participate in Svalex 2014 you have to pass this pre-course assignment.
First you have to select one of three pre-course assignments; Geophysics, Geology or Engineering. Each set of assignments are challenging on the topic indicated in the heading (i.e.
Geology is challenging on the geology questions, but have easy questions related to the two other
topics; geophysics and engineering). Geology students should therefore select the Geology assignment, geophysics students should select the Geophysics assignment and engineering students
should select the Engineering assignment. Choosing the right pre-course assignment according
to your specialization is important also seen from the perspective of forming working groups,
later on, when solving project exercises at Svalbard and aboard the ship.
Each student has to solve one of the pre-course assignments and submit it electronically
by March 30. 2014 to post@svalex.net. NB: Remember to ll in all necessary information
into the attached le SVALEX 2014 - Student personal data.xlsx and attach this le to
your submission of the pre-course project. The submitted project should not be longer than 10
printed A4 pages (using Times New Roman 12 pt and 1.5 line spacing). Any extra pages will
not be considered when evaluating your submission! Write your full name, institution, e-mail
address and the name of the pre-course assignment you have selected (Geophysics, Geology or
Engineering) on top of the rst page. Use references in the text and include a complete list of
references on the last page.
Each student has to solve and submit the assignment selected, individually, even though
cooperation between students and team-work is encouraged. If a student try to duplicate or copy
all or part of another student's assignment, both students will fail the pre-course assignment.
During Svalex 2014 you will visit several localities on Svalbard (Storvola, Festningen, Midterhuken, Billefjorden, Mediumfjellet, Pyramiden, Ebbadalen and Tchermarkfjellet). At some of
these localities you will examine dierent types of sedimentary basin deposits, whereas other
localities demonstrate dierent styles of deformations. Take some time to become familiar with
the geology of the above mentioned localities. We encourage you to use internet and in particular
the Resource-les in solving your assignment (see below for listed resources).
Resource-les: //http://folk.uio.no/hanakrem/svalex/
.
If you have any questions, please contact one of the resource personnel.
Best of luck!
List of content
Pre-course assignments:
Geology pre-course assignment
Geophysics pre-course assignment
Engineering pre-course assignment
Attachment: Dykstra & Parsons displacement model
(primarily for engineering students)
Selected resources
Resource personnel
Advanced resources
1
page
page
page
page
2
3
4
6
page 11
page 11
page 12
Geology pre-course assignment
Problem 1 (Geology)
a) Carbonates equivalent to the Minkinfjellet and Wordiekammen Formations might be interesting targets for hydrocarbons in the Barents Sea Shelf. What is their age of formation
and at which localities during the Svalex eld course/cruise will you be able to sample
rocks from these two units?
b) Source rocks appear in at least in two formations along the Festningen prole. Which
formations are these, and what are their age of deposition? Discuss the formation of
these types of source rocks and their petroleum potential. Are there any nearby potential
reservoir rocks? If so what is the name and age of deposition of these reservoir rocks - if
they exist.
c) At which locality/localities on Svalbard we are visiting during the Svalex cruise do you
expect to see rift basin deposits? What is the age of the rifting and the approximate
extension direction? How wide is the rift? Describe briey or make a sketch (screen dump)
illustrating facies variations within the rift?
d) What is a decollement zone? Where in the stratigraphic record of Svalbard do you nd
regionally extensive decollement zones? How and why were they formed? Explain!
Problem 2 (Geophysics)
a) Explain how seismic acquisition is performed in the following settings:
i) Oshore (i.e. marine)
ii) Onshore
b) Explain why a contrast in acoustic impedance is important for seismic data.
c) What kind of processing techniques can be used to remove random noise from seismic data?
Problem 3 (Engineering)
a) When a volume of gas and oil is produced to the surface, - what happens to the void left
behind in the reservoir? Mention minimum three dierent physical processes that may play
a part in lling the void. Dierentiate between the processes in time and importance.
b) Draw a gure that shows how oil and gas at reservoir conditions are split into oil and gas
at surface conditions. (Remember that oil in the reservoir also contains gas when brought
to the surface and that gas in the reservoir may also contain oil at surface conditions.)
Based on this drawing, dene the volume factor for gas and oil (normally written Bo and
Bg ). Dene also the gas/oil solution ratio, Rs .
c) Since oil in the reservoir contains both gas and oil at surface conditions, - then the reservoir
density of oil has to be proportional to both surface densities of oil and gas.
Show that the density of reservoir oil is written
ρo =
1
(Rs ρgn + ρon ),
Bo
where ρgn and ρon are the surface density of gas and oil, respectively.
2
Geophysics pre-course assignment
Problem 1 (Geology)
a) Explain why it is dicult to obtain good reection seismic data from the outer part of
Isfjorden comparet with central part Isfjorden? There are more than one explanation for
this!
b) When was Svalbard subjected to crustal extension and formation rift basins? There is
more than one rift event.
c) Two or more dierent lithologies exposed on Svalbard represent challenges to the drilling
engineers. What are these lithologies and why do these lithologies represent possible problems? At what stratigraphic levels do these "problem lithologies" occur, and at which
localities to be visited during the Svalex cruise do you expect to see and sample these
lithologies?
d) What is a foreland basin and how is it formed? Only a short simple answer is needed.
e) What is the depositional age the coal beds present around:
Longyearbyen, Barentsburg, Svea and Pyramiden
Problem 2 (Geophysics)
a) The seabottom in the Isfjord area at Svalbard is very hard. Discuss which types of multiple
removal techniques that can be used to eliminate the sea bottom multiples.
b) How would you do a seismic survey in Isjorden in order to minimize problems with reections from the sides of the fjord?
c) Intrusive sills below the seaoor in Isfjorden cannot be mapped by use of traditional seismic
data. Explain why. What other geophysical technique could be implied to identify such
intrusions?
Problem 3 (Engineering)
a) When a volume of gas and oil is produced to the surface, - what happens to the void left
behind in the reservoir? Mention minimum three dierent physical processes that may play
a part in lling the void. Dierentiate between the processes in time and importance.
b) Draw a gure that shows how oil and gas at reservoir conditions are split into oil and gas
at surface conditions. (Remember that oil in the reservoir also contains gas when brought
to the surface and that gas in the reservoir may also contain oil at surface conditions.)
Based on this drawing, dene the volume factor for gas and oil (normally written Bo and
Bg ). Dene also the gas/oil solution ratio, Rs .
c) Since oil in the reservoir contains both gas and oil at surface conditions, - then the reservoir
density of oil has to be proportional to both surface densities of oil and gas.
Show that the density of reservoir oil is written
ρo =
1
(Rs ρgn + ρon ),
Bo
where ρgn and ρon are the surface density of gas and oil, respectively.
3
Engineering pre-course assignment
Problem 1 (Geology)
a) Explain why it is dicult to obtain good reection seismic data from the outer part of
Isfjorden comparet with central part Isfjorden? There are more than one explanation for
this!
b) When was Svalbard subjected to crustal extension and formation rift basins? There is
more than one rift event.
c) Two or more dierent lithologies exposed on Svalbard represent challenges to the drilling
engineers. What are these lithologies and why do these lithologies represent possible problems? At what stratigraphic levels do these "problem lithologies" occur, and at which
localities to be visited during the Svalex cruise do you expect to see and sample these
lithologies?
d) What is a foreland basin and how is it formed? Only a short simple answer is needed.
e) What is the depositional age the coal beds present around:
Longyearbyen, Barentsburg, Svea and Pyramiden
Problem 2 (Geophysics)
a) Explain how seismic acquisition is performed in the following settings:
i) Oshore (i.e. marine)
ii) Onshore
b) Explain why a contrast in acoustic impedance is important for seismic data.
c) What kind of processing techniques can be used to remove random noise from seismic data?
Problem 3 (Engineering)
Storvola is one of the geological sites visited on Svalex excursions. The Storvola mountain is
located south of Lonyearbyen, along the northern shore of the van Keulen fjord.
The Storvola mountain will in this exercise be taken as an example of a typical sandstone
reservoir where production of the in situ oil can be modeled by applying a somewhat simplied
water displacement process called the Dykstra & Parsons displacement model.
a) Use available resources (i.e. the Resource-les or internet) and familiarize yourself with
the Storvola mountain. Verify the stratied layering of the rocks and identify the numbers
of presumingly good packs of reservoir sands (here referenced as layers or ow channels).
b) Make an assessment of the number of layers and estimate the thickness of dierent layers.
Note down the numbers of layers and their thicknesses. (There is no need to be to detailed.
A crude estimate at this point will do.)
Prior to drilling a production well in the Storvola formation, we need to plan a casing program
where dierent casings (steel tubulars) will be set in the well.
c) What could be typical hole sections and casing sizes involved when drilling this well?
4
d) What types of bits will you use for the dierent hole section and discuss advantages/disadvantages
associated with the dierent bit types.
e) What kind of drilling technology makes it possible to drill horizontal wells and maneuver
in thin sandlayers (above water contact and below shale cap rock)?
f) What kind of completion solution can be used for preparing the well for production?
Visit YouTube and have a look at the movie "Oil Driller Breaches Salt Mine Under Lousiana
Lake".
g) What is Karst and what kind of drilling problems can that cause?
h) What is Pressurized Mud Cap Drilling? (Search on YouTube!)
Attached you will nd a description of the Dykstra & Parsons displacement model that you,
later, will use to estimate the production recovery from the Storvola reservoir. Acquaint your
self with the model below by answering the following questions. (The Dykstra & Parson model,
as presented here, is in principle similar to the model used in the Sword program you will be
using during on the Storvola project exercise.)
i) Verify the renumbering criteria in Eq. 11 by averaging over all values 0 ≤ x̃ ≤ 1 in Eq. 4.
[Hint: Averageing=Integration]
Assume we have access to geological and geophysical information about the Storvola reservoir.
Using the Dykstra & Parsons displacement model we have the means to estimate oil recovery
from the reservoir based on the geological data at hand.
As an example: Let's assume that the oil in Storvola is stored in 5 layers. The oil viscosity
is 0.5 mP a · s and the displacing water viscosity is 0.8 mP a · s.
j) Ideally, reservoir data should be used in the table below, but for demonstration purposes,
- the numbers presented will do.
[Hint: Use spreadsheet calculations.]
In practice, use the numbers in the table below even so they have no direct relevance to the
Storvola reservoir. Answer the remaining questions using the number in the table below.
Layer
#
1
2
3
4
5
hi
[m]
17
50
25
37
12
φi
1
0.19
0.23
0.20
0.21
0.16
∆Si
1
0.15
0.15
0.20
0.17
0.20
ki
[mD]
210
200
460
70
60
λwi
λoi
[mD/mPa s]
[mD/mPa s]
-
-
Mi
1
-
∼ vmax,i
[?]
-
k) Renumber the layers according to frontal speed and calculate the water breakthrough times,
using Eq. 14, for the dieren layers.
l) Calculate the water-oil front positions, using Eqs. 10 and 9, for all layers, and for all
breakthrough times.
m) Calculate the recovery, using Eq. 1, as the sum over all layers, for all breakthrough times.
n) Plot recovery as function of breakthrough times.
5
Dykstra & Parsons displacement model 1
We will in the following assume that the Storvola reservoir is buried some 3000 meter below
surface level. The reservoir is perfectly stratied with longitudinal ow channels of homogenous
characteristics. Parameters such as porosity (φ), permeability (k ) and channel height (h) are all
considered constant within each layer but may vary between layers. A "realistic" 3D model of
the the Storvola reservoir consist of staked layers as depicted in Figur 1, where the bulk volume
is Vb = H · L · W .
Figure 1: Water displaces oil in a stratied layered reservoir.
Various models of dierent type and complexity are available for simulating oil production.
One of the more simplistic models is shown in Figure 1. In the Dyrkstra & Parsons displacement
model, the layers are mathematically decoupled except from in the wells. There is no crossow between layers and the displacement within each layer is piston-like with a sharp (vertical)
interface between water and oil. Even though there might be a certain saturation of water
present in all layers (Swc ), only one phase is moving on either side of the oil-water interface.
(The relative permeability in such a system is 1.) All uids are considered incompressible.
Injection and production is completed over the full interval of layers and the pressure dierence
∆p is constant or the ow rate might be considered constant.
Figur 2 displays elements of the Dykstra & Parsons model. With only one layer in the model
a), the production (recovery) of oil is linearly increasing as the water-oil interface is moving
towards the producer. In the two layer model b), oil is produced from both layers until there
is a water breakthrough in layer 1, after which the linear production is somewhat reduced since
only layer 2 is maintaining oil production. In the multi layer model, water breakthrough will
rst occur in layer 1 since the speed of the water-oil interface is highest in this layer. When
breakthrough (rst in layer 1) occurs production is reduced sequentially as one layer after the
other is produced. This is seen in Fig. 2 c) right, as a leveling o of the relative recovery.
The recovery of oil in Fig. 2 c) left, is the volume of displaced oil, or similarly the volume of
displacing water present in the model. The displacing water volume is dened by the position of
the water-oil interface. The water-oil interface position xi is thus, playing a key role in dening
the oil recovery in this model.
By adding up the volume of displaced (produced) oil in Figur 2, we may derive the recovery
factor,
1
Ref.
Spor Monograph, Svein M. Skjæveland and Jon Kleppe, Enhanced oil recovery, Larry Lake and The
Practice of Reservoir Engineering, L.P. Dake
6
Figure 2: Piston ow in a) single -, b)dual - and c) multi layered reservoir.
N
X
R=
hi x̃i φi ∆Si
i=1
N
X
,
where x̃i =
xi
,
L
(1)
hi φi ∆Si
i=1
where φi is the porosity, ∆Si = 1 − Sor − Swc is the dierence between initial and residual
saturations, hi is the channel height and L is the channel length.
Notice that in a multilayered reservoir as in Figur 2, the recovery is given at times ∆T1 , ∆T2 ,
etc. These are water breakthrough times for the dierent layers.
Since each channel (layer) is behaving independently from all other channels, we may use the
same displacement model for all layers. The problem of calculating the oil recovery, as in Eq. 1,
is therefore reduced to calculating the position of the interface fronts in the dierent layers in
relation to the fastest moving front.
7
Single channel model
The movement of the water-oil interface with reference to Figur 2 is dened by Darcy's law, and
in this case for horizontal ow,
∆po
ko
,
, where λo =
L−x
µo
∆pw
kw
= λw
,
, where λw =
x
µw
uo = λo
and ∆po = (p − pprod )
(2)
uw
and ∆pw = (pinj − p),
(3)
where the bulk speed uo = uw for all incompressible uids and ∆p = pinj − pprod = ∆pw + ∆po .
Eective permeability ko and kw , would normally be dierent but here we write; ko = kw = k .
The "intrinsic front velocity" is dened as the actual uid velocity within the porous medium,
where v ≡ dx/dt = u/(φ∆S). Based on Eqs. 2 and 3 and the denition of the intrinsic front
velocity, we nd
dx̃
1
∆p λw
= 2
,
dt
L φ∆S x̃ + (1 − x̃)M
(4)
where x̃ = x/L is the normalized front position and M = λw /λo is the mobility ratio.
Multi channel model
From Figure 2 c), we see that when the water-oil interface in the fastest moving channel has
reached the producer, the interface in all other layers have moved a certain distance away from
the producer. By dening the position of the interface in all channels, xi , relative to the fastest
moving channel, xf , - we may calculate the recovery by direct substitution of x̃i in Eq. 1.
Relating the speed of the interface in channel xi , to the speed of the fastest moving channel
xf , - we may write,
dx̃i
dx̃i dx̃f
=
.
dt
dx̃f dt
(5)
Notice that the real positions is substituted by normalized position without any loss information.
From Eq. 5 it is easy to relate the position of the fastest moving channel to all other channels,
simply by writing,
dx̃i
φf ∆Sf λwi x̃f + (1 − x̃f )Mf
dx̃i
= dt =
,
dx̃
dx̃f
λwf φi ∆Si x̃i + (1 − x̃i )Mi
f
|
{z
}
dt
(6)
Fi
where Eq. 4 is used for all layers i and f , and where Fi is called the heterogeneity factor.
Integration of Eq. 6 from 0 to x̃i and x̃f respectively, yields the expression,
x̃i =
Mi −
Mi2 + Fi (1 − Mi )[x̃2f (1 − Mf ) + 2Mf x̃f ]
Mi − 1
x̃i = Fi
q
1 − Mf
x̃f + Mf x̃f ,
2
when Mi = 1.
,
when
Mi 6= 1
(7)
(8)
The relative position of the interface in any channel is in Eqs. 7 and 8 given as function of
the relative position of the fastest moving interface. With reference to Figur 2 c), we may nd
the position of the water-oil interface in layers 2, 3, 4, 5 and 6 if we know the interface position
8
of the fastest moving layer 1. At breakthrough in layer 1, i.e. xf = 1, we may write the interface
positions in all other layers,
x̃i =
Mi −
q
Mi2 + Fi (1 − Mi )(1 + Mf )
Mi − 1
x̃i = Fi
1 + Mf
2
, when Mi 6= 1
, when Mi = 1.
(9)
(10)
After breakthrough in layer 1, the second fastest channel 4, now has the fastest moving
water-oil interface. Using Eqs. 9 and 10 again, we are able to calculate the front position in the
remaining layers 2, 3, 5 and 6. This process continues until water breakthrough in the slowest
moving channel, namely layer 5.
Renumbering of layers
It is evident from the above deduction that by combining Eqs. 9 and 10 and Eq. 1 we may
calculate the recovery from all layers, as depicted in Figur 2.
From a practical point of view it would be necessary to dene the numbering of layers with
respect to how fast the water-oil interface is moving in each layer. In order to do this we turn
back to the denition of the intrinsic front velocity given in Eq. 4.
Since 0 ≤ x̃ ≤ 1 and the displacement is linearly progressing, we may estimate the average
front velocity by inserting x̃ = 1/2 into Eq. 4.
The renumbering criteria, dierentiating between the various layers, is therefore dened as,
v∝
λw
1
,
φ∆S 1 + M
(11)
where the pressure drop ∆p and the layer length L are irrelevant in the renumbering process.
Time dependence
The time has so fare only been indirectly referenced. In order to plot the recovery as in Figur 2
c), we need to associate the recovery steps to a ceratin time scale.
Time is part of the equation in the denition of the intrinsic front velocity in Eq. 4. Integration
of this equation over the full channel length,
Z 1
[x̃ + M (1 − x̃)]dx̃ =
0
Z ∆t
λw ∆p
0
φ∆S L2
dt
gives the time ∆t as function of front position,
!
φ∆S L2
x̃2
(1 − M ) + M x̃ .
∆t =
λw ∆p
2
(12)
At water breakthrough, x̃ = 1, we nd,
∆t =
φ∆S L2 1
(1 + M ).
λw ∆p 2
(13)
We may now relate a time scale to the time it takes for water to break through in the fastest
channel. With reference to Fig. 2, where layer 1 is the fastest channel, we get the relative time
for water breakthrough in the various layers,
9
˜ i = ∆ti = φi ∆Si λ1 1 + Mi ,
∆t
∆t1
φ1 ∆S1 λi 1 + M1
(14)
˜ i is a normalized time, where ∆t
˜ i = 1 is the time when water break through in the fastest
∆t
channel.
Water cut
After break through in the fastest layer (layer with the fastest moving water - oil interface),
water will be part of the surface production. The water cut is dened as the relative water rate
compared to the total production of oil and water.
WC =
qw
,
qw + qo
(15)
where WC = 0 before water break through and where WC = 1 after all channels have been
produced.
After water break through in the fastest moving layer, water will continue to ow through
that layer at a constant rate,
qwi = Ai λwi
∆p
,
L
(16)
in accordance to Darcy law.
The oil rate in the layers which have not yet experienced water break through is indirectly
given by Eq. 4,
qoi = Ai λoi
∆p
1
.
L x̃i + (1 − x̃i )Mi
(17)
The water cut is therefore written,
j
X
WC =
j
X
i=1
N
X
Ai λwi
1
Ai λwi +
Ai λoi
x̃
+
(1
− x̃i )Mi
i
i=1
i=j+1
.
(18)
The water cut as well as the recovery can be plotted as function of time, as described above.
10
Selected resources
Problem 1:
• Johnsen, S.O., Mørk, A., Dypvik, H. & Nagy, J. 2002: Outline of the Geology of Svalbard.
11 pp.
• Download the e-module "Introduction to carbonates" here:
• SvalSim (GEO2000)
• Nøttvedt, A., Livbjerg, F., Midbøe, P.S., & Rasmussen, E. 1992: Hydrocarbon potential
of the Central Spitsbergen Basin. In: Vorren, T.O., Bergsager, E., Dahl-Stamnes, Ø.A.,
Holter, E., Johansen, B., Lie, E., & Lund, T.B. (Eds.): Arctic Geology and Petroleum
Potential. NPF Special Publlication 2, p. 333 - 361.
Problem 2:
• Rafaelsen, B. 2004: Seismic resolution and frequency ltering:
• Use e-modules found on www.learninggeoscience.net/ (click GeoPhysics => Modules =>
GeoPhysics => Acquisition / Processing): Geophysical Principles Seismic Equipment Logistics Recording OBS acquisition VSP Data Principles VSP Data Applications
• SvalSim (GEO2000)
Problem 3:
• http://www.ipt.ntnu.no/emodules
(Username: emodules, Password: IPT2007@@)
• Search for "error propagation" on the internet
Resource personnel
Arild Andresen (arild.andresen@geologi.uio.no),
Geir Elvebakk(geelv@statoil.com),
Sverre Ola Johnsen (Sverre.O.Johnsen@geo.ntnu.no),
Hans Arne Nakrem (h.a.nakrem@nhm.uio.no),
Bjarne Rafaelsen (bjarne.rafaelsen@ig.uit.no).
Problem 1:
Problem 2: Jan Inge Faleide (j.i.faleide@geologi.uio.no),
Rolf Mjelde (rolf.mjelde@geo.uib.no),
Martin Landrø (mlan@ipt.ntnu.no),
Bent Ole Ruud (Bent.Ruud@geo.uib.no),
Egil Tjåland (tjaland@ipt.ntnu.no),
Bjarne Rafaelsen (bjarne.rafaelsen@ig.uit.no).
Problem 3: Jon Kleppe (kleppe@ipt.ntnu.no),
Svein Skjæveland (svein.m.skjaeveland@uis.no),
Ole Torsæther (olet@ipt.ntnu.no),
Tom Jelmert (tom.age.jelmert@ntnu.no),
Jann Rune Ursin (jann-rune.ursin@uis.no).
11
Advanced resources
You are not required to use these, they are mainly for those with special interests in a particular
topic.
• Aga, O.J., Dalland, A., Elverhøi, A., Thon, A. & Worsley, D. 1986: The geological history
of Svalbard. 121 pp. Aske Trykkeri AS, Stavanger.
• Brown, A.R. 1999: Interpretation of three-dimensional seismic data, 5th edition. AAPG
Memoir 42, Tulsa, Oklahoma, pp. 514.
• Haremo, P. & Andresen, A. 1992: Tertiary decollement thrusting and inversion structures
along Billefjorden and Lomfjorden Fault Zones, East Central Spitsbergen. In: Larsen,
R.M., Brekke, H., Larsen, B.T., & Tallrås, E. (Eds.): Structural and Tectonic Modelling
and its Application to Petroleum Geology. NPF Special Publication 1, p. 481 - 494.
• Harland, W. B. 1997: The Geology of Svalbard. Geological Society Memoir 17, 521 pp.
Alden Press, Oxford.
• Johansen, A.E., Kibsgaard, S., Andresen, A., Henningsen, T., & Granli, J.R., 1994: Seismic modelling of a strongly emergent thrust front, West Spitsbergen Foldbelt, Svalbard.
American Assocoation of Petroleum Geologists Bulletin 78, p. 1018-1027.
• Johannessen, E.P. & Steel, R.J. 1992: Mid-Carboniferous extension and rift-inll sequences
in the Billefjorden Through, Svalbard. In: Dallmann, W.K., Andresen, A. & Krill, A (Eds.):
Post-Caledonian tectonic evolution of Svalbard. Norsk Geologisk Tidsskrift 72, p. 35-48.
• Larssen, G.B., Elvebakk, G., Henriksen, L.B., Kristensen, S-E., Nilsson, I., Samuelsberg,
T.J., Svånå, T.A., Stemmerik, L. & Worsley, D. 2002: Upper Palaeozoic lithostratigraphy
of the Southern Norwegian Barents Sea. NPD Bulletin 9, 76 pp., 63 gs., 1 tbl.
• Marshak, S. 2001: Earth-Portrait of planet. W.W. Norton & Company, Inc. 734 pp. ISBN
0-393-97423-5.
http://www.wwnorton.com/college/titles/geology/earth/emedia.htm
• Nøttvedt, A., Livbjerg, F., Midbøe, P.S., & Rasmussen, E. 1992: Hydrocarbon potential
of the Central Spitsbergen Basin. In: Vorren, T.O., Bergsager, E., Dahl-Stamnes, Ø.A.,
Holter, E., Johansen, B., Lie, E., & Lund, T.B. (Eds.): Arctic Geology and Petroleum
Potential. NPF Special Publlication 2, p. 333 - 361.
• http://www.owlnet.rice.edu/~ceng671/ ,
particularly chapter 3 (http://www.owlnet.rice.edu/~ceng671/CHAP3.pdf), referring to
http://www.owlnet.rice.edu/~ceng571/
• http://www.owlnet.rice.edu/~ceng571/CHAP1.pdf, many examples from Spitsbergen
and Bjørnøya
• http://www.modlog.com/talks/fesq_2001/ppframe.htm
• http://www.jgmaas.com/scores/facts.html
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