GullfaksVillage2012
IOR with a diverging agent from China
Petter Eltvik
Discipline leader Gullfaks
Classif
ication:
Interna
GullfaksVillage2012 assignment - part A
2 - Classification: Internal
GullfaksVillage2012 assignment - part A
The main purpose of Part A is to demonstrate an understanding of
challenges related to tail-end production at Gullfaks main field:
1. Study the Gullfaks paper (Ref 2) and the Åm report (Ref 3).
2. Make an overview evaluation of the recovery factor for Gullfaks main field to date and
how it varies across the field in the different fluid segments and formations (Brent, Cook,
Statfjord and Lunde). From the Base Ness 1 structural map (Attachment 3.3.4 in RSP07),
locate the H1 segment which is relatively isolated. By looking at all the maps in RSP07 (Ref
1), make an estimate of how many similar independent segments there are at Gullfaks main
field. With independent we mean that the pressure communication to the rest of the field is
limited. Explain why there are differences in oil recovery between the different fluid
segments and formations?
3. Based on the IOR measures in Section 5 in the Åm-report, rank measures according to
the potential for the Gullfaks main field. List pro and contra for each of the IOR measure at
Gullfaks main field
3 - Classification: Internal
Some Norwegian IOR projects (Source Petoro)
4Classification: Internal
2012-01-11
GullfaksVillage2012 assignment - part B
Gullfaks flow diversion project
• R&D cooperation between Statoil and CNPC.
• 1000 ton chemicals bought from company in China.
Injecting chemicals (silica based) into the injector
A-35.
Bypassed oil
剩余油饱和度分布图—— 01/06/2008
457200
457600
458000
458400
B-37
6784000
6784000
A-1H
6783200
6783200
6783600
6783600
A-38A
A-2AH
A-5H
A-38
6782800
So
0.96
6782800
A-39A
A-17
0.64
0.48
A-35
6782400
6782400
0.8
0.16
Oil
457200
457600
0
458000
2011-08-18
• The chemicals shall move into the reservoir and
form micro gel particles, which will stick to the
surface of the pores and thereby reducing the
permeability in invaded zones.
• The water will be forced to find new paths and
invade less water flooded areas.
458400
100 200 300 400 500m
1:10000
5 - Classification: Internal
6782000
6782000
0.32
Injection water
• The chemicals is classified as yellow, due to less
than 1% of aluminates. It is environmentally
acceptable and unproblematic to use.
• Hit bypassed oil and increase the oil recovery.
6
Illustration of water diverging
6 - Classification: Internal
2011-08-18
Introduction to Abio gel
• Abio gel is compound, consisting primarily of Sodium silicate. When Abio gel is brought into contact with
divalent cations (i.e. Ca and Mg) in formation- or seawater it reacts to form a microcrystalline suspension
which may become a stiff gel if concentration of divalent cations exceeds about 1 %. Otherwise it
behaves as a cement paint coating the rock matrix.
The following text
and illustration is
provided by CNPC
Abiogel coat
• narrow the flow channels gradually
• keep certain permeability
• in favor of indepth fluid diversion
Abiogel is actually a gel used in chromatography
and is also a brand name for cement paint
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HMS
• Abio gel-A (Abio gel) are HMS tested to
yellow. It is environmentally green but not
on the PLONOR list and therefore yellow. It
is yellow in health due to high pH.
• Abio gel-B (Calcium Chloride) is green and
on the PLONOR list.
• Alternative chemicals from other suppliers
are mostly red.
8 - Classification: Internal
Main Technical Specifications of Abio gel*
• Main agent – Abio gel: milk white or white particles or powder
• Apperance of abio-gel: transparent or offwhite
• gelation time:4~24h
• density of gel:1.0-1.05 g/cm3
• suitable temperature: 30-200 oC, thermal stable for a long period in 140 oC
• Salinity stability: no upper limit, the higher the better
• suitable reservoirs: sandstone or conglomerate with high permeability ,high heterogeneity. For
fractures and large pores are not suitable.
*:text and pictures from CNPC
9 - Classification: Internal
Inorganic gel
Field experience with Abio gel in China
To our knowledge CNPC has used Abio gel in several reservoirs in the Tarim and
Dagang basins, covering a with a wide range of properties.
In most cases the treatment has resulted in increased oil recovery
Dagang
Tarim
basin
10 - Classification: Internal
basin
Zhouquingzhuang – Dagang oil field
Sedimentary condition: Fluvial – fractured.
Reservoir pressure, temperature and oil viscosity: 260 bar, 99 oC and 1,5 mPas.
Water type and salinity: NaHCO3 and 13700 mg/l
Average values for porosity and permeability: 0,22 and 18 mD (generally some injection problems)
Typical formation depth, thickness and well distance: 3150 m, 10 m and 300 m
Example: Injector Qi24-1, supporting producers Qi24-3 and Qi24-6
Injection scheme for Abio gel
(spacer fluid 20 m3 every 500 m3.
Chemicals are dissolved in
formation water)
Volume
(m3)
Preliminary slug:1 % KCl
500
Front slug:1.5 % A+0.5 % KCl
1000
Main slug: 0.75 % A+0.5 % KCl
1100
Rear slug: 1 % KCl
500
Injection
Injection
rate
Pressure
(m3/d)
(bar)
60-80
Between 220
and 300. Normal
inj. pressure
increases from
about 258 to 275
NB: solid gel is not formed in the reservoir in this case
11 - Classification: Internal
Combined effect in
the two producers
Oil rate increased
100 %, watercut
reduced from 63 to
41 %
12
Studied pilot area: Lower Brent, segment
H1
• Segment selected for a water based chemical method.
• STOOIP in lower Brent is 20,3 MSm³ oil.
• Lower Brent in H1 has ”only” 57 % recovery factor.
• Potential 2 - 5 MSm³ mobile oil left.
• Relatively isolated segment.
• A lot of data is collected in this area. It was the first
production area and therefore a lot of good, initial
data.
• 2 active wells in lower Brent, A-35 (injector) and A39A (producer).
• 2 active producers in upper Brent, B-37 and A-38A.
• Pressure communication between B-37 and lower
Brent. No communication with A-38A?
• Problem with H2S in A-39A. B-37 may also give a H2S
problem.
GullfaksVillage2012 assignment - part B
IOR-challenge 1. Existing H1 model with faults and new production wells
IOR-challenge 2. Existing H1 model with permeability modifications
IOR-challenge 3. Existing H1 model with transmissibility multiplicators between cells
IOR-challenge 4. Existing H1 model with permeability modifications and 2 chemicals.
IOR-challenge 5. Existing H1 model with results from production log in A-35
IOR-challenge 6. Existing H1 model without consideration of environmental issues
IOR-challenge 7. Modified H1 model to historymatch chemical injection in well A-35
13 - Classification: Internal
H1 reservoir model
Layer 44, ER-1
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2011-03-28
Layer 48, R-2
Thank you
Presentation title
Presenters name
Presenters title
E-mail address, tel: +00 00 00 00
www.statoil.com
15 - Classification: Internal