1. Technology for a better society 1 Large Scale Tertiary CO 2 EOR in Mature Water Flooded Norwegian Oil Fields Erik Lindeberg, SINTEF Petroleum Research TCCS-8, Trondheim June 16. to June 18. 2015

2. Technology for a better society Results: 23 selected mature water flooded North Sea oil fields was selected as candidates for tertiary CO 2 injection When the fields were exhausted due to water flooding, CO 2 flooding gave 320 million Sm 3 EOR oil (7 % of OOIP or 20 % relative increase in yield) The operating and capital costs of the concept (redesign of platforms, transport, capture, injection of excess CO 2 ) are to large extent covered by the value of EOR oil even at the present low oil prices 2 2

3. Technology for a better society 3 This oil is produced with negative CO 2 footprint even if all the EOR oil is combusted and the CO 2 from combustion is taken into account

4. Technology for a better society Study of CO 2 for EOR and storage in mature oil fields in the North Sea The objective of study: – Select suitable oil fields for CO 2 flooding for EOR – Calculate the EOR potential – Find the CO 2 storage capacity in the oil fields and nearby saline aquifers which can be used as buffer capacity to obtain stable CO 2 deliveries – Calculate cost and economics Study done by SINTEF Petroleum Research, July 2012, for NPD and is an update of a study done by them in 2007 for the BIGCO2 project (Holt, T. and Lindeberg, E. 2007: EOR and CO 2 disposal – economic and capacity potential in the North Sea. 4 th Trondheim Conference on CO 2, Transport and Storage, June 2007, Trondheim, Norway). Part of BIGCO2 Phase II KMB project including 18 Norwegian and 30 UK oil fields 4 4

5. Technology for a better society 5 Tertiary CO 2 in the North Sea? Fields that are water flooded and located in the North Sea are indicated with and arrow

6. Technology for a better society Selection of field candidates 40 oil fields on production in the Norwegian North Sea were selected for screening 23 oil fields chosen for CO 2 flooding Skade/Utsira Formation and Frigg area chosen as saline aquifers for excess CO 2 Screening criteria excluded fields due due to: – Size (too small) – Initial gas cap – Earlier gas flooding – Earlier WAG (gas) In some of the chosen oil fields only part of the field with was flooded with CO 2 due to that only one of the formations in the field had been water flooded 6 6

7. Technology for a better society 23 selected water flooded fields with possible start of CO 2 injection and estimated remaining resources at start 7 Oil field Start Year Remaining resources at start mill. Sm 3 Alvheim203067.9 Balder202096.7 Brage202099.0 Ekofisk2030529.7 Eldfisk2030330.0 Embla202037.2 Gullfaks2025218.3 Gyda202053.5 Hod203468.7 Jotun202020.2 Oseberg Øst202064.4 Ringhorne Øst202522.2 Snorre2032222.1 Statfjord Brent2020291.0 Statfjord Nord202036.9 Statfjord Øst202026.4 Sygna202011.5 Tor203081.4 Tordis202549.0 Valhall2034253.5 Veslefrikk202065.8 Vigdis202579.3 Volund202511.4 Total2736.1

8. Technology for a better society Techno-economical infrastructure model SINTEF Petroleum Research has developed a techno-economical infrastructure model for large scale deposition of CO 2 in oil reservoirs and aquifers, which was used (Holt and Lindeberg, 2004), CO 2 from industrial sources. Compressed and fed into main pipeline. Branch pipelines Main pipeline infrastructure Oil reservoirs. Oil producers buy CO 2 according to needs. Aquifers Excess CO 2 is deposited in aquifers. 8 Export terminal (Emden) 8

9. Technology for a better society 9 A techno-economic model for predictions of CO 2 EOR in the North Sea Techno-economic model EOR model Field data CO 2 transportation cost model Equipment cost data Deposition scenarios Aquifer deposition costs

10. Technology for a better society 10 The EOR module - approach Generic reservoir model with real heterogeneities – 1.1 million cells model from SPE 10 th comparative study – stochastic reservoir model, shallow marine depositions – up-scaled to a 2016 cells model Water injection followed by CO 2 injection is simulated – Eclipse reservoir simulator – 216 different runs with varying process and geological and parameters – similar approach for CO 2 WAG Functions are fitted to the simulated production curves – Oil production – Water production – Gas production

11. Technology for a better society 11 Use of the EOR module Fit functions – V oil =V oil (PV inj, q inj, PV s,  o,  o, , k z ) – V water =V water (PV inj, q inj, PV s,  o,  o, , k z ) – V gas =V gas (PV inj, q inj, PV s,  o,  o, , k z ) Find the parameters that are valid for the specific reservoir Use the model to calculate the CO 2 incremental oil Pv inj = injected volume (PV) Q inj = injection rate (PV/year) PV s = starting time for gas injection (PV injected at start of gas injection)  o = oil density (kg/m 3 )  o = oil viscosity (cP)  = heterogeneity exponent (used as fitting parameter) K z = vertical permeability multiplier (used as fitting parameter)

12. Technology for a better society 12 Example of production profile calculated by the module

13. Technology for a better society 13 Example of cumulative production profile calculated by the module

14. Technology for a better society 14 Production profile field example Water and gas production profiles included

15. Technology for a better society CO 2 injection rate in the oil fields (Base case) 15

16. Technology for a better society Cumulative CO 2 injected (Base case) 16

17. Technology for a better society EOR oil production rate(Base case) 17

18. Technology for a better society Cumulative production of EOR oil (base case) 18

19. Technology for a better society 19 Comparing this work with previous CO 2 EOR study performed on the Gullfaks field StudyConceptInjection rate PV/year Injection period years EOR yield % Statoil (2000) Grinestaff (2000) CO 2 WAG0.045229.7 This workCO 2 WAG (1:1)0.038208.3 This workContinuous CO 2 0.038207.8

20. Technology for a better society 20 Compering this work with previous CO 2 EOR study performed by the operator of Ekofisk field StudyConceptCO 2 injection rate Mtonne/year EOR yield % Jensen et al. (2000)CO 2 WAG5.05.6 This workCO 2 WAG (1:1)7.37.8 This workContinuous CO 2 14.56.5

21. Technology for a better society CO 2 balance for the Base case and WAG case 21

22. Technology for a better society Cost module CO 2 pipeline system and branches – Calculated for min 100 bar in main pipeline and min 70 bar in branches. Wells - New injection and production wells. – No. of injection wells dependant on injection rate ; 15 000 bbl/day CO 2 per well (sandstone), 7 500 bbl/day (chalk) Oil production system modification – System modified to handle massive CO 2 breakthrough. Description of system described by Holt and Lindeberg (2004) CO 2 compressor – Investment cost related to load (corr. to injection rate and pressure, Turton et al. 2001) CO 2 drying plan t – Drying after compression. Use solid desiccant. Cost calc. after Koht and Riesenfeld (1971) Other cost – Engineering cost and cont. (25%) Aquifer deposition cost – Excess CO 2 deposited in aquifers. Cost for injection wells and compressibility capacity (ZEP project 2001b) 22

23. Technology for a better society 23 Incremental oil recovery for tertiary CO 2 injection

24. Technology for a better society Economic analysis End year of field oil production is taken into account when to start CO 2 injection in the different fields (first year 2020) Reduced peak delivery of CO 2, by spreading out start year for CO 2 injection in the different fields (from 2020 to 2034) Operators pay a price for CO 2 (CO 2 cost) from the main infrastructure CO 2 is recycled after breakthrough, thus decreasing the amount of CO 2 imported EOR project is terminated when net cash flow becomes negative Base case parametersValue Oil prize Peak CO 2 rate CO 2 cost Cost per well Interest rate CO 2 transp. cost (main pipeline) 90 USD /bbl 70 mill tonnes/year 25 USD/tonne 75 mill USD /well 7 % 8.5 USD/tonne 24

25. Technology for a better society Base case results for 23 oil fields Total well cost, bill. USD24 Total investment, bill.USD42 Total NPV, bill. USD40 Total oil recovery, % OOIP60 Total EOR oil, mill. Sm 3 320 Total EOR oil, % of OOIP7 Total stored CO 2 in oil fields, bill. tonnes 1.3 Total stored CO 2 in aquifers, bill. tonnes 1.7 25

26. Technology for a better society 26 NPV at 90 USD/bbl as function of interest rate CO 2 cost

27. Technology for a better society NPV as function of oil price and CO 2 cost at 7% discount rate 27

28. Technology for a better society Conclusions Screening of oil fields for CO 2 EOR in the Norwegian North Sea has shown 23 possible candidates with a total potential of 250 – 340 mill Sm 3 of extra oil from 2020, corresponding to 5 – 7 % of OOIP. Total investment 42 billion USD 70 million tonnes of CO 2 injected per year for 40 years Net present value (NPV) 40 billion USD at 7% interest (oil prize 90 USD/bbl, CO 2 cost 25 USD/tonne) 1.3 Giga tonnes of CO 2 stored in the oil fields 1.7 Giga tonnes of CO 2 stored in buffer aquifers The amount of CO 2 stored is much larger than the CO 2 formed by combustion of the EOR oil 28

29. Technology for a better society 29 Mapping the potential of CO2 storage opportunities in mature oil fields... 29

30. Technology for a better society 30

31. Technology for a better society 31

32. Technology for a better society 32

33. Technology for a better society 33

34. Technology for a better society 34

35. Technology for a better society 35 Total project economy field example

36. Technology for a better society Need for wells for storing excess CO 2 36

37. Technology for a better society Storage rate of excess CO 2 in aquifers 37