Role of Ionic Composition and Interaction in Oil-Water-Rock Systems during Enhanced Oil Recovery Processes involving Low-Salinity Fluid and CO2 Injection

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Today, exploration for new oilfields is a high-risk venture due to the low oil price. Therefore, a logical lower-cost alternative is to target and extract residual oil from the already discovered and developed oil reservoirs, particularly the Canadian light-oil reservoirs with an estimated oil reserve of 5.5 billion barrels. Even a single percent improvement in the recovery of oil from these reservoirs will yield rich dividends for Canada. My program has a direct relevance to such reservoirs in Canada and elsewhere, where the traditional waterflood has performed poorly due to unfavorable rock wettability and high post-flood residual oil saturation, thus making a difference between a successful and a marginal project, particularly in the current low-oil price environment. The unfavorable rock wettability, in particular, leads to poor relative permeability characteristics for the oil, and this in turn, causes the premature breakthrough of the injected water in production wells resulting in a much lower-than-expected oil recovery factor.**** My research aims to find solutions to overcome or diminish the effects of unfavorable rock wettability by making changes in the ionic composition and salinity of the injected water. In this program, I will also explore how some of these light-oil Canadian reservoirs can be utilized, concomitantly, to sequester CO2 and recover oil. Therefore, this program has dual objectives: EOR and partial CO2 sequestration through an EOR process.**** A systematic approach has been charted to meet the program objectives through a well-defined work plan comprising both modeling and experimental studies. The program includes a fundamental study of water geochemistry and key rock-fluid geochemical reactions under various ionic compositions. This is followed by a study of CO2 EOR with an optimized composition of the injected water to partly sequester CO2 in the reservoir. It will generate a new water chemistry to improve waterflood oil recovery as well as quantify the CO2 sequestration potential during CO2 EOR processes.**** Geochemical reactions and transport models developed in the program will be validated through specially-designed laboratory tests to study oil-rock-brine interactions, wettability alteration, relative permeability and surface-charge behavior, ionic transport, and finally, the oil recovery and CO2 fixation in the rock. This will be followed by additional validation using representative rock-fluid samples and data from a few selected Canadian light-oil reservoirs to establish the lab-to-field linkage of the program outcomes.**** During the course of the program, I will provide comprehensive research-based training in advanced modeling and laboratory studies to 7 HQPs, who will also engage synergistically in scholarly outreach, contributions and interactions with peers in dissemination of our findings through refereed journals, conferences and other such knowledge-sharing platforms, like forums and workshops.***