Fluid-rock interactions and its implications on EOR: Critical analysis, experimental techniques and knowledge gaps

Characterization of fluid-rock interactions is essential for a broad range of subsurface applications such as understanding fluid flow in porous medium and enhanced oil recovery predictions. Enhanced oil recovery (EOR) is crucial in oil and gas production operations, it entails injecting fluids into the reservoir to enhance productivity. When fluids are injected, interactions occur between the injected fluids and the reservoir rock/fluids; and the outcomes of fluid-rock interactions critically impact the fluid flow in porous medium and the associated oil recovery. Furthermore, the associated changes in reservoir properties (porosity, permeability etc.) and flow behavior (i.e. wettability alteration and relative permeability changes) demonstrate variability at a range of scales. Thus, it is of great importance to understand these interactions at multiple scales and their ensuing implications on EOR. This study therefore provides a comprehensive review of the types of fluid-rock interactions in both carbonate and sandstone reservoirs. Fluid-rock interactions quantification methods, their applicability and principle of measurements were summarized. The implications of fluid-rock interactions were extensively discussed. Finally, we identified and highlighted some research gaps and provided recommendations for future research directions. The findings of this review show that despite numerous studies on fluid-rock interactions such as adsorption, dissolution/precipitation, clay swelling/fines migration and wetting characteristics in porous media involving EOR fluids, the exact mechanism of action of these fluids during EOR applications in rock/oil/brine system, is still not fully understood. The extent and implications of these fluid-rock interactions on EOR depends on several factors/parameters. Such factors include the injected fluid type and chemical composition, rock type and mineralogical composition, brine pH, salinity and composition. Moreover, the review shows that all the fluid-rock interactions quantification techniques have some limitations either in their applicability, measurement range, or uncertainty level. Therefore, the incorporation of various imaging and characterization tools would be required for improved understanding the fluid-rock interactions. The review, therefore, provides critical insights in the area of fluid-rock interactions and its implications on EOR. Thus, the findings of this review are expected to enhance our knowledge and provide better understanding of fluid-rock interactions and thereby reduce the uncertainties associated with laboratory-scale predictions, reservoir management and enhanced recovery of oil. (C) 2022 The Author(s). Published by Elsevier Ltd.