Abstract
Carbonate reservoirs are considered to be in the range of mixed to oil wetting state. Their present wetting state seems unfavorable to recover more oil via conventional waterflooding especially as the water cut increases with huge residual oil saturation. In recent years, studies have shown that tuning the injected brine chemistry can help decrease the oil-wetness, resulting in additional oil recovery and reduction in residual oil saturation. Thus, rock wettability is being dictated by the surface chemistry associated with the water-film stability between crude oil and the rock surface. This study presents series of experiments conducted on Middle Eastern carbonate core plugs at high pressure and high temperature in order to determine the impact of sulfate ions in smart brine on oil recovery. Each experiment was initially conducted using the formation brine, and subsequently, various versions of seawater with varying sulfate concentrations were used. Coreflooding experiments showed an additional recovery of about 7–9 % oil originally in core when sulfate concentration was increased while none when decreased. Decrease in rock oil-wetness was observed to be responsible for the improved recovery as demonstrated by the contact angle analysis. Similar trend was observed with the zeta potential analysis which further proved that the magnitude of surface charge alteration contributes immensely to wettability modification toward more water-wetness.
Similar content being viewed by others
Abbreviations
- D :
-
Diameter
- IRF:
-
Incremental recovery factor
- IS:
-
Ionic strength
- \(K_{\mathrm{g}}\) :
-
Air permeability
- \(K_{\mathrm{L}}\) :
-
Liquid permeability
- \(K_{\mathrm{o}}\) (\(S_{\mathrm{wirr}})\) :
-
Effective permeability to oil at irreducible water saturation
- kppm:
-
Thousands part per million
- L :
-
Length
- \(\varnothing \) :
-
Porosity
- OOIC:
-
Original oil in core
- PV:
-
Pore volume
- RF:
-
Recovery factor
- \(S_{\mathrm{or}}\) :
-
Residual oil saturation
- \(S_{\mathrm{wirr}}\) :
-
Irreducible water saturation
- TDS:
-
Total dissolved solids
- \(\zeta \) :
-
Zeta
References
Anderson, W.: Wettability literature survey-part 1: rock/oil/brine interactions and the effects of core handling on wettability. J. Pet. Technol. 38(10), 1125–1144 (1986)
Austad, T.: Understanding of the EOR potential using smart water. In: Sheng, JJ. (ed.) Enhanced Oil Recovery Field Case Studies, pp. 712. Gulf Professional Publishing: Waltham (2013)
Austad, T., Shariatpanahi, S., Strand, S., Black, C., Webb, K.: Conditions for a low-salinity enhanced oil recovery (EOR) effect in carbonate oil reservoirs. Energy Fuels 26(1), 569–575 (2011)
Awolayo, A., AlSumaiti, A.M., Sarma, H.: An experimental study of smart waterflooding on fractured carbonate reservoirs. Paper presented at the ASME 2014 33rd international conference on ocean, offshore and Arctic engineering, San Francisco, USA (2014a)
Awolayo, A.N., Sarma, H.K., Al-Sumaiti, A.M.: A laboratory study of ionic effect of smart water for enhancing oil recovery in carbonate reservoirs. Paper presented at the SPE EOR conference at oil and gas west Asia, Muscat, Oman (2014b)
Farooq, U., Tweheyo, M.T., Sjøblom, J., Øye, G.: Surface characterization of model, outcrop, and reservoir samples in low salinity aqueous solutions. J. Dispers. Sci. Technol. 32(4), 519–531 (2011)
Gupta, R., Smith Jr. P., Willingham, T., Lo Cascia, M., Shyeh, J., Harris, C.: Enhanced waterflood for middle east carbonate cores—impact of injection water composition. Paper presented at the SPE middle east oil and gas show and conference, Manama, Bahrain (2011)
Hiorth, A., Cathles, L., Madland, M.: The impact of pore water chemistry on carbonate surface charge and oil wettability. Transp. Porous Media 85(1), 1–21 (2010)
Høgnesen, E., Strand, S., Austad, T.: Waterflooding of preferential oil-wet carbonates: Oil recovery related to reservoir temperature and brine composition. Paper presented at the SPE Europec/EAGE annual conference, Madrid, Spain (2005)
Jadhunandan, P., Morrow, N.: Effect of wettability on waterflood recovery for crude-oil/brine/rock systems. SPE Reserv. Eng. 10(1), 40–46 (1995)
Kwak, H.T., Yousef, A.A., Al-Saleh, S.: New insights on the role of multivalent ions in water-carbonate rock interactions. Paper presented at the SPE improved oil recovery symposium, Tulsa, Oklahoma, USA (2014)
Lager, A., Webb, K.J., Black, C., Singleton, M., Sorbie, K.: Low salinity oil recovery—an experimental investigation1. Petrophysics 49(1), 28–35 (2008)
Lager, A., Webb, K.J., Black, C.J.J.: Impact of brine chemistry on oil recovery. Paper presented at the 14th European symposium on improved oil recovery, Cairo, Egypt (2007)
Ligthelm, D., Gronsveld, J., Hofman, J., Brussee, N., Marcelis, F., van der Linde, H.: Novel waterflooding strategy by manipulation of injection brine composition. Paper presented at the EUROPEC/EAGE conference and exhibition, Amsterdam, The Netherlands (2009)
McGuire, P., Chatham, J., Paskvan, F., Sommer, D., Carini, F.: Low salinity oil recovery: an exciting new EOR opportunity for Alaska’s north slope. Paper presented at the SPE western regional meeting, Irvine, California (2005)
Pierre, A., Lamarche, J., Mercier, R., Foissy, A., Persello, J.: Calcium as potential determining ion in aqueous calcite suspensions. J. Dispers. Sci. Technol. 11(6), 611–635 (1990)
Puntervold, T.: Petroleum Engineering. University of Stavanger, Norway (2008)
RezaeiDoust, A., Puntervold, T., Strand, S., Austad, T.: Smart water as wettability modifier in carbonate and sandstone: a discussion of similarities/differences in the chemical mechanisms. Energy Fuels 23(9), 4479–4485 (2009)
Rod, S.: Quantification of uncertainty in recovery efficiency predictions: lessons learned from 250 mature carbonate fields. Paper presented at the SPE annual technical conference and exhibition, Denver, Colorado (2003)
Sheng, J.: Enhanced Oil Recovery Field Case Studies. Gulf Professional Publishing, Houston (2013a)
Sheng, J.J.: Review of surfactant enhanced oil recovery in carbonate reservoirs. Adv. Pet. Explor. Dev. 6(1), 1–10 (2013b)
Strand, S., Austad, T., Puntervold, T., Høgnesen, E.J., Olsen, M., Barstad, S.M.F.: Smart water for oil recovery from fractured limestone: a preliminary study. Energy Fuels 22(5), 3126–3133 (2008)
Strand, S., Høgnesen, E.J., Austad, T.: Wettability alteration of carbonates—effects of potential determining ions (\(\text{ Ca }^{2+}\) and \(\text{ SO }_{4}^{2-}\)) and temperature. Colloids Surf. A Physicochem. Eng. Asp. 275(1), 1–10 (2006)
Takamura, K., Chow, R.S.: The electric properties of the bitumen/water interface Part II. Application of the ionizable surface-group model. Colloids Surf. 15, 35–48 (1985)
Tang, G.Q., Morrow, N.R.: Influence of brine composition and fines migration on crude oil/brine/rock interactions and oil recovery. J. Pet. Sci. Eng. 24(2), 99–111 (1999)
Tweheyo, M., Zhang, P., Austad, T.: The effects of temperature and potential determining ions present in seawater on oil recovery from fractured carbonates. Paper presented at the SPE/DOE symposium on improved oil recovery, Tulsa, Oklahoma, USA (2006)
Webb, K., Black, C., Al-Ajeel, H.: Low salinity oil recovery-log-inject-log. Paper presented at the SPE/DOE symposium on improved oil recovery, Tulsa, Oklahoma, USA (2004)
Yi, Z., Sarma, H.: Improving waterflood recovery efficiency in carbonate reservoirs through salinity variations and ionic exchanges: a promising low-cost smart-waterflood approach. Paper presented at the Abu Dhabi international petroleum conference and exhibition, Abu Dhabi, UAE (2012)
Yousef, A., Al-Saleh, S., Al-Kaabi, A., Al-Jawfi, M.: Laboratory investigation of novel oil recovery method for carbonate reservoirs. Paper presented at the Canadian unconventional resources and international petroleum conference, Calgary, Alberta, Canada (2010)
Zahid, A., Shapiro, A., Skauge, A.: Experimental studies of low salinity water flooding in carbonate reservoirs: a new promising approach. Paper presented at the SPE EOR conference at oil and gas West Asia, Muscat, Oman (2012)
Zhang, P., Austad, T.: Wettability and oil recovery from carbonates: effects of temperature and potential determining ions. Colloids Surf. A Physicochem. Eng. Asp. 279(1), 179–187 (2006)
Zhang, P., Tweheyo, M.T., Austad, T.: Wettability alteration and improved oil recovery in chalk: the effect of calcium in the presence of sulfate. Energy Fuels 20(5), 2056–2062 (2006)
Zhang, P., Tweheyo, M.T., Austad, T.: Wettability alteration and improved oil recovery by spontaneous imbibition of seawater into chalk: impact of the potential determining ions \(\text{ Ca }^{2+}\), \(\text{ Mg }^{2+}\), and \(\text{ SO }_{4}^{2-}\). Colloids Surf. A Physicochem. Eng. Asp. 301(1), 199–208 (2007)
Acknowledgments
The authors appreciate the financial support provided by The Petroleum Institute (PI) in conducting this research work and the permission to present this paper. Authors are obliged to ADCO for providing the experimental data and ZADCO UZFDS Laboratory for hel** with effluent sample analysis.
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Awolayo, A., Sarma, H. & AlSumaiti, A. An Experimental Investigation into the Impact of Sulfate Ions in Smart Water to Improve Oil Recovery in Carbonate Reservoirs. Transp Porous Med 111, 649–668 (2016). https://doi.org/10.1007/s11242-015-0616-4
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s11242-015-0616-4