Low Salinity EOR Effects After Seawater Flooding in a High Temperature and High Salinity Offshore Sandstone Reservoir
- Zahra Aghaeifar (University of Stavanger) | Tina Puntervold (University of Stavanger) | Skule Strand (University of Stavanger) | Tor Austad (University of Stavanger) | Behrouz Maghsoudi (University of Stavanger) | Jose da Costa Ferreira (University of Stavanger)
- Document ID
- Society of Petroleum Engineers
- SPE Norway One Day Seminar, 18 April, Bergen, Norway
- Publication Date
- Document Type
- Conference Paper
- 2018. Society of Petroleum Engineers
- 5.4 Improved and Enhanced Recovery, 1.6 Drilling Operations, 5.2 Reservoir Fluid Dynamics, 1.6.9 Coring, Fishing, 5.4 Improved and Enhanced Recovery, 5.2 Reservoir Fluid Dynamics
- High temperature, Low salinity, Seawater flooding, EOR, Sandstone
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Many offshore reservoirs have been seawater-flooded, which could affect the low salinity EOR potential. This paper evaluates the low salinity EOR potential after seawater flooding for a high temperature (148 °C), high salinity (~170000 ppm) sandstone reservoir. Secondary oil recovery by low salinity injection is compared to secondary seawater and tertiary low salinity water injection.
Oil recovery experiments were performed at reservoir temperature using preserved reservoir cores. To mimic initial wetting conditions of the original oil reservoir, the cores were mildly cleaned and restored with the formation water and reservoir crude oil. Secondary seawater injection was performed, as well as secondary and tertiary low salinity water injection. Solid-brine surface reactivity tests were performed to evaluate chemical interactions, initial wetting, and potential for wettability alteration in the reservoir system.
The pH of the first produced water in the oil recovery tests indicated favorable initial wetting conditions, i.e. mixed wettability, which is necessary for obtaining low salinity EOR effects by wettability alteration. However, the oil recovery tests showed no tertiary low salinity EOR effects after seawater flooding. Secondary low salinity injection resulted in 6-10% higher oil recovery compared to that obtained by secondary seawater injection. Low salinity injection normally generates cation exchange on the pore mineral surface promoting a pH increase and good conditions for observing wettability alteration. The produced water sample pH show that unfavorable Crude Oil-Brine-Rock interactions reduced the pH increment and the low salinity EOR potential after seawater injection. The surface reactivity tests also confirmed higher EOR potential by secondary low salinity injection, seen by a higher pH increase, which during low salinity injection triggers wettability alteration of the rock surface towards more water-wet, thereby recovering more oil.
The results show that low salinity injection into a seawater-flooded reservoir is likely to be less efficient due to unfavorable chemical interactions and reduced pH increase, and therefore there is a reduced potential for wettability alteration. However, for this high temperature and high salinity reservoir secondary low salinity water injection could be an efficient EOR method.
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Aghaeifar, Z., Strand, S., Austad, T.., 2015a. Influence of formation water salinity/composition on the low salinity EOR effect in high temperature sandstone reservoirs. Energy & Fuels, 29(8): 4747–4754. https://doi.org/10.1021/acs.energyfuels.5b01621.
Aghaeifar, Z., Strand, S., Puntervold, T.., 2015b. Adsorption/desorption of Ca2+ and Mg2+ to/from kaolinite clay in relation to the low salinity EOR effect. IOR 2015 – 18th European Symposium on Improved Oil Recovery, Dresden, Germany, 14-16 April. https://doi.org/10.3997/2214-4609.201412132.
Aksulu, H., Håmsø, D., Strand, S.., 2012. Evaluation of low salinity EOR-effects in sandstone: Effects of temperature and pH gradient. Energy & Fuels 26(6): 3497–3503. https://doi.org/10.1021/ef300162n.
Austad, T., Rezaeidoust, A. and Puntervold, T., 2010. Chemical mechanism of low salinity water flooding in sandstone reservoirs. SPE Improved Oil Recovery Symposium, Tulsa, Oklahoma, USA, 24-28 April. SPE-129767-MS. https://doi.org/10.2118/129767-MS.
Buckley, J.S. and Morrow, N.R., 1990. Characterization of crude oil wetting behavior by adhesion tests. SPE/DOE Seventh Symposium on Enhanced Oil Recovery, Tulsa, Oklahoma, April 22-25. https://doi.org/10.2118/20263-MS.
Burgos, W.D., Pisutpaisal, N., Mazzarese, M.C.., 2002. Adsorption of quinoline to kaolinite and montmorillonite. Environmental Engineering Science, 19(2): 59–68. https://doi.org/10.1089/10928750252953697.
Chou, L. and Wollast, R., 1985. Steady-state kinetics and dissolution mechanisms of albite. American Journal of Science, 285(December): 963–993. https://doi.org/10.2475/ajs.285.10.963.
Chow, R.S. and Takamura, K., 1988. Electrophoretic mobilities of bitumen and conventional crude-in-water emulsions using the laser Doppler apparatus in the presence of multivalent cations. Journal of Colloid and Interface Science, 125(1): 212–225. https://doi.org/10.1016/0021-9797(88)90070-7.
Fogden, A., 2012. Removal of crude oil from kaolinite by water flushing at varying salinity and pH. Colloids and Surfaces A: Physicochemical and Engineering Aspects, 402: 13–23. https://doi.org/10.1016/j.colsurfa.2012.03.005.
Ligthelm, D.J., Gronsveld, J., Hofman, J.P.., 2009. Novel waterflooding strategy by manipulation of injection brine composition. EUROPEC/EAGE annual conference and exhibition, Amsterdam, The Netherlands, 8-11 June. SPE-119835-MS. https://doi.org/10.2118/119835-MS.
Madsen, L. and Lind, I., 1998. Adsorption of Carboxylic Acids on Reservoir Minerals From Organic and Aqueous Phase. SPE-37292-PA. SPE Reservoir Evaluation & Engineering, 1(01): 47–51. https://doi.org/10.2118/37292-PA.
Piñerez Torrijos, I.D., Austad, T., Strand, S.., 2016. Linking low salinity EOR effects in sandstone to pH, mineral properties and water composition. SPE Improved Oil Recovery Conference, Tulsa, Oklahoma, USA, 11-13 April. SPE-179625-MS. https://doi.org/10.2118/179625-MS.
Piñerez Torrijos, I.D., Puntervold, T., Strand, S.., 2017a. Impact of temperature on the low salinity EOR effect for sandstone cores containing reactive plagioclase. Journal of Petroleum Science and Engineering, 156: 102–109. https://doi.org/10.1016/j.petrol.2017.05.014.
Reinholdtsen, A.J., RezaeiDoust, A., Strand, S.., 2011. Why such a small low salinity EOR - potential from the Snorre formation? 16th European Symposium on Improved Oil Recovery, Cambridge, UK, 12-14 April. https://doi.org/10.3997/2214-4609.201404796
RezaeiDoust, A., Puntervold, T. and Austad, T., 2011. Chemical Verification of the EOR Mechanism by Using Low Saline/Smart Water in Sandstone. Energy & Fuels, 25(5): 2151–2162. https://doi.org/10.1021/ef200215y.
Seccombe, J., Lager, A., Jerauld, G.., 2010. Demonstration of low-Salinity EOR at interwell scale, Endicott field, Alaska. SPE Improved Oil Recovery Symposium, Tulsa, OK, USA, 24-28 April. SPE-129692-MS. https://doi.org/10.2118/129692-MS.
Shimoyama, A. and Johns, W.D., 1972. Formation of alkanes from fatty acids in the presence of CaCO3. Geochimica et Cosmochimica Acta, 36(1): 87–91. https://doi.org/10.1016/0016-7037(72)90122-6.
Springer, N., Korsbech, U. and Aage, H.K., 2003. Resistivity index measurement without the porous plate: A desaturation technique based on evaporation produces uniform water saturation profiles and more reliable results for tight North Sea chalk. International Symposium of the Society of Core Analysts Pau, France, 21-24 September.
Strand, S., Austad, T., Puntervold, T.., 2014. The impact of plagioclase on the low salinity EOR-effect in sandstone. Energy & Fuels, 28(4): 2378–2383. https://doi.org/10.1021/ef4024383.
Strand, S., Puntervold, T. and Austad, T., 2016. Water based EOR from clastic oil reservoirs by wettability alteration: A review of chemical aspects. Journal of Petroleum Science and Engineering, 146: 1079–1091. https://doi.org/10.1016/j.petrol.2016.08.012.
Winoto, W., Loahardjo, N., Xie, S.X.., 2012. Secondary and tertiary recovery of crude oil from outcrop and reservoir rocks by low salinity waterflooding. SPE Improved Oil Recovery Symposium, Tulsa, Oklahoma, USA, 14-18 April. SPE-154209-MS. https://doi.org/10.2118/154209-MS.