Induced carbonate dissolution: Impact of brine chemistry in CO2 foam

Foam CO 2 might be considered an efficient alternative to reduce gas mobility and produce favorable mobility ratios. It offers significant advantages, particularly in heterogeneous or fractured reservoirs due to its ability to block highly permeable layers or divert the injected fluid from fractures into the matrix. In the present work, a surfactant solution made of different ionic compositions was co-injected into outcrop Edwards Limestone to determine the impact of brine chemistry on carbonate dissolution upon CO 2 foam injection. The development in differential pressures (DP) during continuous co-injection of sc-CO 2 and different surfactant solutions (NaCl, NFB, CB) shows that unwanted chemical reactions (dissolution/precipitation) compromise the rock integrity by more acid formation and wormholing. Rock-fluid-foam interactions indicate that the total heat in the rock-fluid-foam systems is 6.9 mJ NaCl foam , 19.3 mJ NFB foam , and 37.8 mJ CB foam systems. On the other hand, the total heat for the fluid-foam interactions is 11.5 mJ NaCl foam , 12.5 NFB foam , and 20.4 mJ CB foam . The demicellization of the foam formulations could have led to calcite dissolution. The synergy between ITC and core flooding experiments elucidates the impact of the brine chemistry on calcite dissolution during foam-assisted CO 2 sequestration at both microscopic and macroscopic scales. • CO 2 foam-induced Dissolution at Microscopic and Macroscopic Scales. • CO 2 foam-reservoir rock interactions. • CO 2 foam-fluid interactions. • Impact of foam chemistry on non-uniform dissolution.