Experimental Study on Enhanced Oil Recovery by Low Salinity Water Flooding on the Fractured Dolomite Reservoir

Document Type : Research Article


1 Faculty of Petroleum and Chemical Engineering, Science and Research Branch, Islamic Azad University, Tehran, I.R. IRAN

2 IOR Research Institute, NIOC, Tehran, I.R. IRAN

3 Chemical and Petroleum Engineering Department, Sharif University of Technology, Tehran, I.R. IRAN

4 Chemical Engineering Faculty, University of Calgary, Calgary, Alberta, T2N 1N4, CANADA


Enhanced Oil Recovery from carbonate reservoirs is a major challenge especially in naturally fractured formations where spontaneous imbibition is a main driving force. The Low Salinity Water Injection (LSWI) method has been suggested as one of the promising methods for enhanced oil recovery. However, the literature suggests that LSWI method, due to high dependence on rock mineralogy, injected and formation water salt concentration and complexity of reactions is not a well-established technology in oil recovery from carbonate reservoirs. The underlying mechanism of LSWI is still not fully understood. Due to lack of LSWI study in free clay dolomite fractured reservoir, and to investigate of anhydrate composition effect on oil recovery in this type of reservoir, the main purpose is the experimental evaluation of oil recovery from one of the Iranian naturally fractured carbonated (dolomite containing anhydrate and free clay) reservoirs using LSWI. For this purpose, a set of experiments including spontaneous and forced imbibition is conducted. To obtain the optimum salt concentration for oil recovery, the secondary mode of the spontaneous imbibition tests is performed by seawater in various salt concentrations at the reservoir temperature (75°C). Also, the tertiary recovery mode is subsequently applied with optimum brine salinity. The lab results reveal that by decreasing the injected water salt concentration, oil production increases. Furthermore, in order to upscale the experimental results to the field scale, a more precise dimensionless-time correlation is used. Due to some inconsistencies over the influence of mechanisms on LSWI oil recovery, the mineral dissolution, pH-increase mechanisms, and wettability alteration are also studied. The results indicate that wettability alteration is the main mechanism and mineral dissolution may be the predominant mechanism of the improved oil recovery in the studied reservoir. It is noticed, the elevation of pH led to enhanced oil recovery when high dilution of low salinity water is implemented. 


Main Subjects

[1] Al-Shalabi E.W., Sepehrnoori K., Pope G., Mohanty K., “A Fundamental Model for Predicting Oil Recovery Due to Low Salinity Water Injection in Carbonate Rocks”, In Proceedings of the Society of Petroleum Engineers Energy Resources Conference Port of Spain.; SPE-169911-MS (2014).
[2] Shehata A.M., Nasr-El-Din H.A., Reservoir Connate Water Chemical Composition Variation Effect on Low-Salinity Waterflooding, SPE Journal., SPE 171690 (2014).
        DOI: http://dx.doi.org/10.2118/171690-MS
[3]   Austad T., Shariatpanahi S., Strand S., Black C.J.J., Webb K.J., Conditions for a Low-Salinity Enhanced Oil Recovery (EOR) Effect in Carbonate Oil Reservoirs, Energy Fuels., 26: 569–575 (2011).
[4] Mahani H., Keya A.L., Berg S., Bartels W.B., Nasralla R., Rossen W., Insights into the Mechanism of Wettability Alteration by Low-Salinity Flooding (LSF) In Carbonates, Energy Fuels; 293:1352–1367 (2015)DOI: https://doi.org/10.1021/ef5023847
    [5] AlameriW., Teklu T.W, Romano M.G, Kazemi H., Alsumaiti A.M., Experi Mental & Numerical Modeling of Low Salinity Waterflood in a Low Permeability Carbonate, Society of Petroleum Engineering, USA, 27-30(2015).
[7] Zaeri M.R., Hashemi R., Shahverdi H., Sadeghi M., Enhanced Oil Recovery from Carbonate Reservoirs by Spontaneous Imbibition of Low Salinity Water, Petroleum Science, 15: 564-576 (2018).
[8] Ebrahimzadeh Rajaee SH., Gerami SH., Safekordi A.A, Ganjeh Qazvini M. Review on Low Salinity Injection in Carbonated Reservoirs and Challenges, Nashrieh Shimi va Mohandesi Shimi Iran (NSMSI),38(3): 305-317 (2019). [in Persian]
[11] Zhang P., Austad T. “The Relative Effects of Acid Number and Temperature on Chalk Wettability”, SPE International Symposium on Oilfield, onepetro.org (2005).
[12] Yi Z., Sarma H.K., “Improving Water Flood Recovery Efficiency in Carbonate Reservoirs Through Salinity Variations and Ionic Exchanges: A Promising Low-Cost Smart-Water Flood Approach”, In Proceedings of the Abu Dhabi International Petroleum Conference and Exhibition UAE.; SPE-161631-MS (2012).
[13] Al-Harrasi A.S., Al-Maamari R.S. “Laboratory Investigation of Low Salinity Waterflooding for Carbonate Reservoirs”, Abu Dhabi International, onepetro.org( 2012)
[14] Karimi M., Al-Maamari R.S., Ayatollahi Sh., Mehranbod N., Wettability Alteration and Oil Recovery by Spontaneous Imbibition of Low Salinity Brine into Carbonates: Impact of  Mg2+, SO42- and  Cationic Surfactant, Journal of Petroleum Science and Engineering. (2016).
[15] Rashid S., Mousapour M.S., Ayatollahi SH., Vossoughi M., Hoseinali Beigy A., Wettability Alteration in Carbonates During Smart Waterflood: Underlying Mechanisms and the Effect of Individual Ions, Colloids and Surfaces A: Physicochem. Eng. Aspects. (2015).
 [16] Standnes D.C., Austad T. Wettability Alteration in Chalk: 1. Preparation of Core Material and Oil Properties, Journal of Petroleum Science Engineering, 28 111–121 (2000),
[17] Strand S., Hogenson E.J., Austad T. Wettability Alteration of Carbonates Effect of Potential Determining Ions and Temp, Colloids and Surface A: Physicochemical and Engineering Aspect, 257: 1-10 (2006).
[18] Hognesen E.J., Strand S., Austad T., Water-flooding of Preferential Oil-Wet Carbonates: Oil Recovery Related to Reservoir Temperature and Brine Composition, SPE Journal, SPE 94166; SPE Europe/EAGE Annual Conference Madrid Spain (2005).
[19] Webb K.J., Black C.J.J., Edmonds I.J., “Low Salinity Oil Recovery–The Role of Reservoir Condition Core Floods”, In 13th European Symposium on Improved Oil Recovery.EAGE. (2005).
[20] Wickramathilaka S. “Aspects of Oil Recovery by Spontaneous Imbibition and Wettability Alteration”. Ph.D.Dissertation, University of Wyoming Laramie Wyoming USA, (2010).
[22] Mahani H., Berg S., Ilic D., Bartels W. B., Joekar-Niasar V., Kinetics of the Low Salinity Water Flooding Effect Studied in a Model System. SPE Journal, SPE 165255 (2013).
[23] Hiorth A., Cathles L.M., Madland M.V., Impact of Pore Water Chemistry on Carbonate Surface Charge and Oil Wettability, Transport in Porous Media., 85(1): 1-212010.
       DOI: 10.1021/acs.energyfuels.5b01621
[24] Yousef A.A., Al-Saleh S., Al-Kaabi A., Al-Jawfi M., “Laboratory Investigation of The Impact of Injection-Water Salinity and Ionic Content on Oil Recovery From Carbonate Reservoirs”. SPE Reservoir Evaluation & Engineering. SPE-137634-PA 14(5):
DOI: https://doi.org/10.2118/137634-PA.
[25] Pu H., Xie X., Yin P., Morrow N.R., “Low Salinity Waterflooding and Mineral Dissolution”, SPE  Annual Technical Conference, SPE-134042-MS (2010).
        DOI: https://doi.org/10.2118/134042-MS    
[26] Qiao C., Li L., Johns R. T., Xu J.A., Mechanistic Model for Wettability Alteration by Chemically Tuned Waterflooding In Carbonate Reservoir, SPE Journal., SPE170966 (2015).
[28] Zahid A., Shapir A.A., Skauge A., “Experimental Studies of Low Salinity Water Flooding Carbonate: A New Promising Approach”, Presented at the SPE EOR Conference at Oil and Gas West Asia Muscat Oman, SPE-155625-MS (2012).
[30] Safavi M.S, Masihi M., Safekordi A.A, Ayatollahi Sh, Sadeghnejad S., Effect of SO42- Ion Exchanges and Initial Water Saturation on Low Salinity Water Flooding in the Dolomite Reservoir Rocks, Journal of Dispersion Science and Technology, (2019).
        DOI: 10.1080/01932691.2019.1614026
[31] Ligthelm D.J., Gronsveld J.Hofman J.P., Brussee N.J., Marcelis F., van der Linde H.A., Novel Waterflooding Strategy by Manipulation of Injection Brine Composition, SPE Journal., SPE 119835 (2009).
[32] Sandengen K., Arntzen O.J., “Osmosis During Low Salinity Water Flooding”, 17th European Symposium on Improved Oil Recovery. SI. Petersburg. Russia. (2013).
        DOI: 10.3997/2214-4609.20142608
[33]   Bartels W.B., Mahani H., Berg S., Hassanizadeh S.M., Literature Review of Low Salinity Water Flooding from a Length and Time Scale Perspective, Fuel. 236: 338-353 (2019).
[34] RezaeiDoust A., Puntervold T., Strand S., Austad T., Smart Water as a Wettability Modifier in Carbonate and Sandstone: A Discussion of Similarities/ Differences in the Chemical Mechanisms, Energy & Fuels., 23: 4479–4485 (2009).
        DOI: 10.1021/ef900185e
[35] Zhang Y., Xie X., Morro N.R., “Waterflood Performance by Injection of Brine with different Salinity for Reservoir Plugs”. SPE Annual Technical Conference and Exhibition Anaheim California USA. (2007).
        DOI: https://doi.org/10.2118/109849-MS
[36] Aksulu H., Ha msø D., Strand S., Puntervold T., Austad T., Evaluation of Low-Salinity Enhanced Oil Recovery Effects in Sandstone: Effects of the Temperature and pH Gradient, Energy Fuels, 26(6): 3497–503. 2012.
[37] Chandrasekhar S., Mohanty K.K., Study of Brine Composition on Oil-Rock Interaction by Atomic Force Microscopy, Journal of Petroleum Science and Engineering, (2018).
[38] Sohrabi M., Mahzari P., Farzaneh S.A., Mills J.R, BP: Tsolis P., Ireland S., “Novel Insights into Mechanisms of Oil Recovery by Low Salinity Water Injection”, SPE Conference in Manama. Bahrain., SPE172778-MS (2015).
[39] Test Method 143,"Institute of petroleum".
[40] Ma S., Morrow N.R., Zhang X., Generalized Scaling of Spontaneous Imbibition Data for Strongly Water-Wet Systems, Journal. Petroleum. Science. Engineering, 18-165 (1997).
        DOI: https://doi.org/10.2118/95-138
[41] "Scalesoftpitzer.v13.xls" Commercial Software (2009)
 [43] Nasralla R., Sergienko E., Masalmeh S., van der Linde H., Brussee N., Mahani H., Potential of Low-Salinity Waterflood to Improve Oil Recovery in Carbonates: Demonstrating the Effect by Qualitative Core Flood, SPE Journal; SPE172010 (2010).
[44] Austad T., RezaeiDoust A., Puntervold T., “Chemical Mechanism of Low Salinity Water Flooding in Sandstone Reservoirs”. “SPE Improved Oil Recovery Symposium Tulsa”., SPE 129767 (2010).
 [45] Aghaeifar Z., Strand S., Austad T., Puntervold T., Aksulu H., Navratil K., Storas S., Hamso D., Influence of Formation Water Salinity/Composition on the Low-Salinity Enhanced Oil Recovery Effect in High-Temperature Sandstone Reservoirs, Energy and Fuels. (2015).
        DOI: 10.3997/2214-4609.20142608
[46] Zhou D., Jia L., Kamath J., Kovscek A.R., Scaling of counter-Current Imbibition Processes in Low-Permeability Porous Media, J. of Pet. Sci. and Eng.; 33(1-3). 61-74 (2002)
[47] Behbahani H., Blunt M.J., Analysis of Imbibition in Mixed-Wet Rocks Using Pore-Scale Modeling, SPE Journal., SPE 90132-P (2005).
[48] Awolayo A., Sarma H., Nghiem L., Thermodynamic Modeling of Brine Dilution-Dependent Recovery in Carbonate Rocks with Different Mineralogical Content, Energy Fuels., 32: 8921–8943 (2018).