Fast Evaluation of Caprock Strength Sensitivity to Different CO2 Solutions Using Small Sample Techniques

Abstract The Draupne shale is a rock formation functioning as overburden for gas reservoirs in the Norwegian Sea and potentially caprock future CO 2 storage locations well. In this paper, was exposed to several fluids: gas, supercritical , dissolved brine, well brine dry air. motivation exposure tests investigate whether injected reservoir coming into contact with could change caprock’s mechanical properties increase risk leakage of stored . addition, systematic study will provide more insight various processes susceptible altering shale’s shear strength acoustic velocity, such clay hydration, mineral dissolution, capillary forces. Due low permeability shale, experiments were conducted on mm-sized disk samples, reducing fluid diffusion allowing many repeated disks close by original core. punch method, where small circle punched out used assess strength, while continuous wave technique ultrasonic velocity. Results show that not noticeably sensitive sense no additional weakening observed presence compared exposure. This last effect probably due poor matching between pore salinity strength.