GullfaksVillage2012 IOR with a diverging agent from China

1. GullfaksVillage2012IOR with a diverging agent from China Petter Eltvik Discipline leader Gullfaks

2. GullfaksVillage2012 assignment - part A

3. 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

4. Some Norwegian IOR projects (Source Petoro)

5. GullfaksVillage2012 assignment - part BGullfaks 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. • The chemicals is classified as yellow, due to less than 1% of aluminates. It is environmentally acceptable and unproblematic to use. • 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. • Hit bypassed oil and increase the oil recovery. Bypassed oil

6. Illustration of water diverging 6

7. Abiogel coat 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 • 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

8. 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.

9. Inorganic gel 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

10. 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 basin Tarim basin

11. 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 NB: solid gel is not formed in the reservoirin this case

12. 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 A-39A (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. 12 Studied pilot area: Lower Brent, segment H1

13. 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

14. H1 reservoir model Layer 44, ER-1 Layer 48, R-2

15. Thank you Presentation title Presenters name Presenters title E-mail address, tel: +00 00 00 00 www.statoil.com