Experimental Investigation of the Role of Rock Components in Enhanced Oil Recovery Using Low Salinity Water Flooding in Shadegan Oil Field

Document Type : Research Paper

Authors

1 Department of Chemical and Petroleum Engineering, Sharif University of Technology, Tehran, Iran

2 Department of Petroleum, Engineering and Technical Faculty, Islamic Azad University Central Tehran Branch, Tehran, Iran

Abstract

Due to the complex nature of carbonate reservoirs, mechanisms behind low salinity water injection (LSWI) in these reservoirs are not well understood compared to sandstone ones. Using a limestone core and crude oil from one of the wells of the Shadegan oil field, a core injection test was performed with a sequence of high salinity-low salinity water. 10-time diluted seawater, as low salinity water, was able to recover 14.5% of initial oil in place (IOIP) following the secondary injection of seawater. In contrast, the tertiary injection of the low salinity bine into artificial pure calcite rock (with petrophysical properties similar to real rock) recovered only 3.4% of IOIP. Using the results of the contact angle test, the improved oil recovery by LSWI is attributed to wettability alteration towards a more water-wet state. However, the amount of wettability alteration in Shadegan oil field limestone (42°) is significantly higher than that of pure calcite rock (16°). Based on the results of zeta potential, the wettability alteration by low salinity water is attributed to the more negative electric charge of the crude oil/brine and rock/brine interfaces. The increasing trend of pH with decreasing the salinity showed that more CO32- adsorption at low salinity reduces the electric charge on the calcite surface. The electric charge of Shadegan oil field limestone, by reducing the salinity of injected water from seawater to 10-time diluted seawater, experienced a greater decrease (7.7 mV) than pure calcite (4.1 mV). XRF results attributed this behaviour to the presence of impurities such as silica, sulphate, and phosphate in the Shadegan oil field limestone.

Keywords


[1]. Mezher T, Fath H, Abbas Z, Khaled A (2011) Techno-economic assessment and environmental impacts of desalination technologies, Desalination, 266, 1–3: 263–273.##
[2]. Einav R, Harussi K, Perry D (2003) The footprint of the desalination processes on the environment, Desalination, 152, 1–3: 141–154. ##
[3]. Al-Shalabi E W, Sepehrnoori K (2016) A comprehensive review of low salinity/engineered water injections and their applications in sandstone and carbonate rocks, Journal of Petroleum Science and Engineering, 139: 137–161. ##
[4]. Tang G Q, Morrow N R (1999) Influence of brine composition and fines migration on crude oil/brine/rock interactions and oil recovery, Journal of Petroleum Science and Engineering, 24, 2–4: 99–111. ##
[5]. Ligthelm D J, Gronsveld J, Hofman J, Brussee N, Marcelis F, van der Linde H (2009) Novel waterflooding strategy by manipulation of injection brine composition, Presented at the EUROPEC/EAGE Conference and Exhibition. ##
[6]. Webb K, Lager A, Black C (2008) Comparison of high/low salinity water/oil relative permeability, Presented At The International Symposium of The Society of Core Analysts, Abu Dhabi, UAE, 29. ##
[7]. Nasralla R A, Sergienko E, Masalmeh S K, van der Linde H A, Brussee N J, Mahani H, Suijkerbuijk B, Alqarshubi I (2014) Demonstrating the potential of low-salinity waterflood to improve oil recovery in carbonate reservoirs by qualitative coreflood, Presented at the Abu Dhabi International Petroleum Exhibition and Conference. ##
[8]. Romanuka J, Hofman J, Ligthelm D J, Suijkerbuijk B, Marcelis F, Oedai S, Brussee N, van der Linde H, Aksulu H, Austad T (2012) Low Salinity EOR in Carbonates, Presented at the SPE Improved Oil Recovery Symposium. ##
[9]. Fathi S J, Austad T, Strand S (2010) Smart Water’ As A Wettability Modifier In Chalk: The Effect of Salinity and Ionic Composition, Energy and Fuels, 24, 4, 2514–2519. ##
[10]. Austad T, Shariatpanahi S, Strand S, Black C, Webb K (2012) Conditions for a low-salinity enhanced oil recovery (EOR) effect in carbonate oil reservoirs, Energy and fuels, 26, 1: 569–575. ##
[11]       Mahani H, Keya A L, Berg S, Nasralla R (2017) Electrokinetics of carbonate/brine interface in low-salinity waterflooding: Effect of brine salinity, composition, rock type, and pH on ζ-potential and a surface-complexation model, SPE Journal, 2, 01: 53–68. ##
[12]. Sharma H, Mohanty K K (2018) An experimental and modeling study to investigate brine-rock interactions during low salinity water flooding in carbonates, Journal of Petroleum Science and Engineering, 165, 1021–1039. ##
[13]. Yousef A A, Al-Saleh S, Al-Kaabi A U, Al-Jawfi M S (2010) Laboratory investigation of novel oil recovery method for carbonate reservoirs, Presented at the Canadian Unconventional Resources and International Petroleum Conference. ##
[14]. Hiorth A, Cathles L, Madland M (2010) The impact of pore water chemistry on carbonate surface charge and oil wettability, Transport in Porous Media, 85, 1: 1–21. ##
[15]. Mahani H, Keya A L, Berg S, Bartels W B, Nasralla R, Rossen W R (2015) Insights into the mechanism of wettability alteration by low-salinity flooding (LSF) in carbonates, Energy and Fuels, 29, 3: 1352–1367. ##
[16]. Alhammadi M, Mahzari P, Sohrabi M (2017) Experimental investigation of the underlying mechanism behind improved oil recovery by low salinity water injection in carbonate reservoir rocks, Presented at the Abu Dhabi International Petroleum Exhibition and Conference. ##
[17]. Wei B, Wu R, Lu L, Ning X, Xu X, Wood C, Yang Y (2017) Influence of Individual Ions on Oil/Brine/Rock Interfacial Interactions and Oil–Water Flow Behaviors in Porous Media, Energy and Fuels, 31, 11: 12035–12045. ##
[18]. Mokhtari R, Ayatollahi S, Fatemi M (2019) Experimental investigation of the influence of fluid-fluid interactions on oil recovery during low salinity water flooding, Journal of Petroleum Science and Engineering, 182: 106194. ##
[19]. Mahani H, Menezes R, Berg S, Fadili A, Nasralla R, Voskov D, Joekar-Niasar V (2017) Insights into the impact of temperature on the wettability alteration by low salinity in carbonate rocks, Energy and Fuels, 31, 8: 7839–7853. ##
[20]. Thompson D W, Pownall P G (1989) Surface electrical properties of calcite, Journal of Colloid and Interface Science, 131, 1: 74–82. ##
[21]. Cicerone D S, Regazzoni A E, Blesa M A (1992) Electrokinetic properties of the calcite/water interface in the presence of magnesium and organic matter, Journal of Colloid and Interface Science, 154, 2: 423–433. ##
[22]. Al Mahrouqi D, Vinogradov J, Jackson M D (2017) Zeta potential of artificial and natural calcite in aqueous solution, Advances in Colloid and Interface Science,  240, 60–76. ##
[23]. Romero C P, Jeldres R I, Quezada G R, Concha F, Toledo P G (2018) Zeta potential and viscosity of colloidal silica suspensions: Effect of seawater salts, pH, flocculant, and shear rate, Colloids and Surfaces A: Physicochemical and Engineering Aspects, 538: 210–218. ##
[24]. Smallwood P (1977) Some aspects of the surface chemistry of calcite and aragonite Part I: An electrokinetic study, Colloid and Polymer Science, 255, 9: 881–886. ##
[25]. Zhang P, Austad T (2006) Wettability and oil recovery from carbonates: Effects of temperature and potential determining ions, Colloids and Surfaces A: Physicochemical and Engineering Aspects, 279, 1–3: 179–187. ##
[26]. Meng W, Haroun M, Sarma H, Adeoye J, Aras P, Punjabi S, Rahman M, Al Kobaisi M (2015) A novel approach of using phosphate-spiked smart brines to alter wettability in mixed oil-wet carbonate reservoirs, Presented at the Abu Dhabi International Petroleum Exhibition and Conference. ##