Pore-Scale Displacement of Heavy Crude Oil During Low Salinity Water Flooding

Dehkordi, Parham Babakhani; Razavirad, Fatemeh; Shahrabadi, Abbas

doi:10.1007/s11242-022-01825-0

Cited by 4 publications

(1 citation statement)

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“…It is likely that the LSE depends on the specific crude oil–brine–rock (COBR) system. In addition, compared to conventional oil, very limited research was conducted on heavy oil. − In this study, our target is offshore heavy oil. To test the potential of injecting a low-salinity brine which is available from a subsurface aquifer, first of all, core-scale coreflooding and spontaneous imbibition tests were conducted and compared among three water sources, i.e., seawater, produced water (PW), and low-salinity aquifer water (LSAW).…”

Section: Introductionmentioning

confidence: 99%

Application of Low-Salinity Waterflooding in Heavy Oil Sandstone Reservoir: Oil Recovery Efficiency and Mechanistic Study

Wang,

Wu,

Shi

et al. 2024

ACS Omega

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Low-salinity water injection (LSWI) is a recently emerged and promising technique to enhance oil recovery. In addition, it is attractive due to its relatively low-cost, environmental friendliness, and sustainability. However, the underlying mechanisms remain unclear, and very limited research has been conducted on heavy oil. To verify the feasibility of injecting a lowsalinity aquifer water (LSAW) to improve the oil recovery of our target offshore heavy oil reservoir, first, a series of experiments on the core scale, including coreflooding and spontaneous imbibition experiments, were carried out. Furthermore, atomic force microscopy (AFM), contact angle, zeta potential measurement, as well as disjoining pressure calculations based on the Derjaguin− Landau−Verwey−Overbeek (DLVO) theory were carried out to explore the underlying governing mechanism at the microscopic scale. The secondary oil recovery factors of the coreflood tests are 67.11, 70.55, and 77.18% for seawater (SW), produced water (PW), and LSAW, respectively. The additional oil recoveries by LSAW when injected in tertiary modes are 6.38% after SW injection and 5.68% after PW injection. These results indicate that compared with SW and PW which have high brine salinity, the low-salinity brine from the subsurface aquifer (LSAW) can improve oil recovery in both secondary and tertiary modes. In addition, the oil recovery factors from the spontaneous imbibition tests (27.52% by LSAW, 17.32% by PW, and 14.00% by SW) and the insignificant variation of IFTs among the three brines lead to the anticipation that the LSAW can alter the rock to a more water-wet condition compared with SW and PW, thereby giving rise to a higher oil recovery factor in the coreflooding tests. By using AFM imaging and contact angle tests, we proved that the polar asphaltene could desorb from the rock surface and consequently reduce the water contact angle substantially when subjected to low-salinity brine. Furthermore, the zeta potential and the disjoining pressure results indicate that a more repulsive force was developed between oil and the rock under the low-salinity environment, which thereby promotes asphaltene desorption and consequent wettability alteration. Our work has paved the way to apply LSWI to the offshore heavy oil sandstone reservoir.

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