Geochemical simulation of wettability alteration and effluent ionic analysis during smart water flooding in carbonate rocks: Insights into the mechanisms and their contributions

摘要: Abstract Production of oil from carbonate reservoirs has always been challenging. The nature these is complex and heterogeneous, the rock matrix often low permeability unfavorable wettability. Hence, waterflooding as primary method for enhanced recovery (EOR) usually results in non-water-wet reservoirs. Alternatively, salinity/Smart water injection (LSWI) attracted considerable attention widely used improvement rocks. Wettability alteration believed to be cause incremental during LSWI carbonates through two main mechanisms surface charge change dissolution. In this study, experimental data smart coreflooding a sample real field was simulated, focusing on geochemical reactions dynamic wettability alteration. contribution different investigated careful ionic analysis at elevated temperatures. Oil recoveries four brines with salinities were matched, compositions effluents studied individually. Acceptable history match achieved between geochemically simulated concentrations. trends Ca2+ Mg2+ concentrations indicated presence Calcite Dolomite dissolution all cases. case seawater injection, underestimated while overestimated, which shows dominance higher salinities. As salinity reduced 5000 ppm, became close, translated By decreasing 2000 ppm, trend SO42− concentration observed along overestimation Mg2+, showed mechanism lower According results, proposed therefore concluded mainly mineral dissolution, Moreover, time effect also observed. This study provides simulation approach which, both practical fundamental (mechanistic) aspects are considered. findings can help better understanding underlying their contributions reservoir Furthermore, by using systematic set simulations based analysis, optimal conditions composition could provided maximizing operations, without need numerous, expensive, tedious laboratory experiments.