CASE STORVOLA
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Svalex: Case Storvola:
The Storvola reservoir appraisal project…
In this appraisal project you are going to
evaluate the Storvola reservoir where
hydrocarbons have been found. You have
to get a better understanding of the
geology and make a geological model
describing the different sedimentary facies
in the reservoir, and use logs and facies
properties and facies distributions to fill
petrophysical data into the model to make a
petrophysical model. Then you are going to
simulate a reservoir model that you make,
and decide and plan drilling operations and
production strategies.
You are going to write a report on the job
and make a presentation to be shown on
the last day of Svalex. The best
presentations will get prices.
Your group is a team of geoscientist and
engineers from a small oil company. Your
company has been given a recently
discovered field in a new area to work on –
the Storvola field. The mountain side of
Storvola represents a cross section
through the reservoir. Hydrocarbons have
been found in the wells.
Based on all the information provided and
the integration of technical expertise of
each of the members of the team, your
team needs to submit a written report about
your findings to the board of directors. In
this project you will carry out many of the
tasks an oil company has to do to evaluate
and develop new prospects. Use your
imagination to get reasonable data into
your models. You will have to make
assumptions where data are not available.
Your company is in need of more reserves and the board urges you to better outline the amount
of reserves in the field (appraisal) and propose a development plan based on the information
provided by the data and the geological knowledge of the area.
Based on all the information provided and the integration of technical expertise of each of the
members of the team, your team needs to submit a written report about your findings to the
board of directors. In this project you will carry out many of the tasks an oil company has to do to
evaluate and develop new prospects
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Fig. 1: From ref. 4: Piret Plink-Bjørklund and Ron J Steel.
HSE - Health, Safety, Environment, and Logistics: We want no
accidents of any kind.
Logistics: You will be brought from the ship to
shore by small boats (zodiacs). It takes normally
about 1 – 1.5 hours. Then we will walk to Storvola
for about one hour and spend around 1.5-2 hours in
the outcrop. Return to the ship the same way.
Safety: Take full responsibility of reading and
understanding the safety instructions:
You are responsible for the safety of your
friends and of yourself.
Always stay together with the group. You need
permission from the safety guards to leave the big
group.
At the mountain side it is mandatory to wear a
helmet – also called a hard hat.
Never walk or climb above people. If you have to
move above someone, always make people below
aware before you start to move above them
Fig. 2: Storvola cross section - from Svalsim - Flash animation. Please study Storvola in Svalsim before going into
the field
Learning goals:
The learning goals are to train yourself and your fellow students to…
i. geological models - including the role of
1. Understand the development of
seismic interpretation and well log data to
reservoirs from appraisal to
build such models.
production. This involves the work
of all disciplines: Geology,
ii. petrophysical models and
geophysics, petrophysics, drilling,
iii. reservoir simulation models.
reservoir engineering and
production
3. Understand the tasks of geology,
geophysics, petrophysics, drilling,
2. Understand the roles of …
reservoir engineering and
production that has to be carried out
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CASE STORVOLA
to do an appraisal of and plan
production of a reservoir.
4. Be sure to take advantage of the
information in Svalsim.
5. This may be the only opportunity
you get to see the inside of a
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reservoir. The Storvola mountain
side is a cross section through the
reservoir. Try to understand the
geological processes that made the
geology you see. How much more
info does this give you than the
seismic section seen in Fig. 15?
Questions to be answered.
Geology: Make a geological model.
At the end of this document you will find more information about the geology of Storvola.
6. Sketch the mountain side from a
distance – from the ship and later
from the rim in front of Storvola.
Take pictures to later add detail to
the sketch. Evaluate the ability of
7. What geological processes created
this reservoir?
8. Identify what types of sedimentary
processes that have been active in
the Storvola reservoir. Refer to Fig.
5 and 6.
9. What is facies, and what can facies
be used for. Ask your geologist to
explain what is facies associations.
Assignment at the rim in front of Storvola.
Two groups will be chosen to present their
results.
11. Sketch the reservoir and assign
facies with descriptive names to the
different layers. The names may
reflect the depositional
environments.
12. Prepare a short 4 minutes
presentation of the reservoir as you
see it from a distance: Including
development history, facies types
and important aspects of geology,
geophysics, petrophysics, reservoir
modeling, drilling and production.
Petrophysics:
13. Make a petrophysical model by
filling petrophysical properties –
porosities, permeabilities, shalyness
etc. into the geological model using
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seismic data to give more
information for the geological model
that you are making – resolution
issues, layer continuity, thinning etc.
10. What facies do you find in this
reservoir? How continuous (laterally
and vertically) are the facies you
identified? Are there any facies that
you would classify as possible
reservoir flow units?
the information provided by the
exploration wells shown at the end
of this document, and the Storvola
outcrop.
14. Walk up to the lower part of the
Storvola outcrop and make
sedimentological studies and logs in
the field to confirm the facies
assumptions you made at the rim.
Complement the previous part with
the information given by the
exploration wells.
You will need to know the
thicknesses of the different layers
for assessing the necessary
resolution of seismic (frequency)
and for later use in the reservoir
simulator (Sword).
(If you measure the thickness of a
particular bed, you may have a good
reference for calculating the
thicknesses of other beds that you
can see on images that you have
taken from a larger distance – the
Svalex: Storvola
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CASE STORVOLA
rim and from the boat. Check these
data against Svalsim).
15. Based of your understanding of the
geological processes having created
this reservoir do the following:
i. Based on the 3 exploration wells (see end of
this document) and the outcrop observations,
assign petrophysical parameters like porosity,
permeability and saturation to the facies across
the profile – based on e.g. studies of grain
characteristics like size, sorting, roundness etc.
To do this you have to use your imagination in
deciding porosity and permeability for the
different facies types.
ii. Some times people make mistakes. Is there any
reason to suspect misplacement or mixup of
log positions in this project?
iii. Suggest ranges of porosities and permeabilities
for the different facies you define.
iv. Estimate net to gross (N/G) from the
geological logs at the end of this Storvola
document. You will have 3 numbers – which
one is more likely for your reservoir?
Geophysics: Evaluate the potential of
seismic data in this project.
16. At what stages in your study would
you use seismic data? Discuss.
17. On a seismic section, you will identify
reflectors.
Drilling & Completion .
24. See Instructions for this part in a
separate document at the end of this
document.. Please note that this part
has its own numbering of questions
etc..
Reservoir engineering. Make a
simulation model.
25. See Instructions for this part in a
separate document at the end of this
document… Please note that this part
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i. What is a reflector? Do you think that
the different layers you observe at
Storvola will act as reflectors? Which
information can you get from an
identified reflector?
18. Try to estimate seismic velocities and
the density of your different layers.
19. Based on the thicknesses of the
observed layers, what frequency range
do you need to be able to detect them
in the seismic data?
20. From pictures taken of the Storvola
mountain side, you may estimate the
thicknesses of the various layers. Use
modeling software to predict what a
seismic trace at 10 different locations
along the reservoir will look like using
normal and reasonably assumed
parameters for the seismic data.
21. Are ther any more descriptive images
of the upper parts of the Storvola
reservoir in Svalsim?
22. You may have observed faulting at
Storvola. Discuss how faults can be
detected on the seismic data.
23. Using Sword, you will be able to play
with simple reservoir simulations. But
more detailed and complete reservoir
models exist for Storvola in Eclipse
format.
has its own numbering of questions
etc..
a.
Reporting your findings.
26. Based on your investigations make a
report and a PowerPoint presentation
where you will present the results of
your study with main focus on the
potential of the reservoir and
recommendations to the board of
directors of your company.
Responsible teachers:
Case responsible: Helge Langeland, Petrophysics / Well logging
Geology: Sverre Ola Johnsen, Arild Andresen, Anders Mattias Lundmark, Hans Arne Nakrem
Geophysics: Egil Tjåland.
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Reservoir engineering: Jann Rune Ursin - Sword responsible, Jan Ivar Jensen
Drilling: Kjell Kåre Fjelde.
References
1. Use the SvalSim program as a general reference. Both pictures and text will help you in constructing a
useful simulation model.
2. Johannessen, Erik P. and Steel, Ron J. 2005: Shelf-margin clinoforms and prediction of deepwater sands.
Basin Research (2005) 17. This publication is rather detailed on clinoforms but also contains interesting
information related to Storvola and the other deposits (mountains) in the van Keulen Fjord.
3. A. Nøttvedt, F. Livbjerg, P.S. Midbøe and E. Rasmussen: Hydrocarbon potential of Central Spitsbergen
Basin. This is a more general publication which contains interesting information of past activities in
localizing hydrocarbons on Svalbard. The article does not contain detailed information on the Storvola
mountain.
4. Mellere, Donatella, Plink-Bjørklund, Piret, Steel, Ronald J. 2002: Anatomy of shelf deltas at the edge of a
prograding Eocene shelf margin, Spitsbergen. Sedimentology (2002) 49, 1181–1206
5. Petter, Andrew L. and Steel, Ronald J.: Hyperpycnal flow variability and slope organization on an Eocene
shelf margin, Central Basin, Spitsbergen
6. Plink-Bjørklund, Piret and Steel, Ron J.: Initiation of turbidity currents: outcrop evidence for Eocene
hyperpycnal flow turbidites,
7. Plink-Bjørklund, Piret: Stacked fluvial and tide-dominated estuarine deposits in high-frequency (fourth
order) sequences of Eocene Central Basin, Spitsbergen.
8. SeisRoX reference: H. Gjøystdal, Å. Drottning, I. Lecomte and M. Branston, 2007. Advances in
quantitative model-assisted seismic interpretation, First Break, 25, 95-102
Fig. 3. The Storvola mountain side showing the positions of the exploration wells and the log data.
Well data: The
locations of the 3
geological logs
made at Storvola
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Fig. 4. Geological model and well trajectories at Storvola.
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The construction of a reservoir model based on the Storvola mountain side…
Geological facies model characterized with
facies types and, layer geometries from
seismics and outcrop studies
Petrophysical model: Petrophysical
properties like porosity, permeability and
saturation are associated to facies types and
entered into the geological model. This gives
a petrophysical model. The resolution is the
same as for the geological model.
Upscaling to larger blocks makes a
virtual reservoir model for simulation
of dynamic behaviour. Note larger
blocks.
Fig. 5: Construction of a simulation model from a geological model via petrophysical model to a simulation model.
The procedure you will use to make a reservoir model from the Storvola mountain side.
Fig. 6: Enlarged section of seismic in the Storvola area.
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Fig. 7 Seismic velocities related to the seismic of Storvola.
Fig. 8: The location of the seismic section through the Storvola area (red line). Check out the seismics and other data
in Svalsim.
Fig. 9 –Next page: Log data and core data derived from geological logs.
Log scales:
Scale porosity: 0 – 0.6
Scale permeability: 0 to 600 mD.
Both scales goes from right towards left
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Fig. 10. Geological logs made by Frode Liestøl
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27.
Fig. 11.
Geological
logs made
by Frode
Liestøl
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