Chemically Tuned Waterflooding in Carbonate Reservoirs: Experimental and Simulation Investigation


Low salinity waterflooding (LSWF) has been widely investigated to reduce the residual oil saturation in swept areas and thus improve oil recovery. Recently, extensive studies on crude oil, brine, and rock system reported that LSWF and increased sulfate ion concentration in the injected water could change rock wettability during waterflooding. The objective of this paper is to provide a deeper understanding the effect of sulfate ion concentration and low salinity waterflooding on oil recovery improvement due to wettability modification by applying experimental and simulation approaches. An experimental model with the properties of the same core was designed to understand the effect of LSWF and sulfate ion concentration on improved oil recovery during the waterflooding process. Reactive transport simulator (CrunchFlow 2007) was used to simulate the experimental result. Once the experimental and simulation results were matched, a sensitivity analysis was done by changing sulfate ion concentration and calculate the wettability index based on chromatographic separation of tracer (SCN-) and sulfate ion (SO42-) to investigate how could affect the sulfate ion concentration on modifying rock wettability. So when the area between SCN- and SO42- increased, the wettability modified toward water wet. The experimental results found that both LSWF and increased sulfate ion concentration three times can improve oil recovery factor by 10% and 19.5%, respectively. The reactive transport simulator results showed that the area between SCN-and SO42- increased as SO42- concentration increased and improved the core wettability toward more water wetness. The temperature has a significant effect on the SO42- adsorption and the high temperature resulted in more SO4 adsorption and the core wettability modified to be more water wetness. Combined two approaches, experimental and simulation, could be a viable technique to understand LSWF and sulfate ion concentration effect on improved rock wettability toward water-wet.

Meeting Name

SPE Kingdom of Saudi Arabia Annual Technical Symposium and Exhibition 2018, SATS 2018 (2018: Apr. 23-26, Dammam, Saudi Arabia)


Geosciences and Geological and Petroleum Engineering

Keywords and Phrases

Concentration (process); Crude oil; Ions; Liquid chromatography; Rocks; Sensitivity analysis; Sulfur compounds; Wetting, Carbonate reservoir; Chromatographic separations; Experimental modeling; Improve oil recovery; Improved oil recovery; Reactive transport; Residual oil saturation; Simulation approach, Oil well flooding

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Article - Conference proceedings

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© 2018 Society of Petroleum Engineers (SPE), All rights reserved.

Publication Date

01 Apr 2018

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