Air injection tests in two argillaceous rock formations: Experimental results and modelling

摘要

Air flow through two argillaceous rock formations is investigated on the basis of laboratoryrnwork and its modelling to help in the interpretation of the results. Priority in the experimental program hasrnbeen given to study the volume change response of these initially water saturated materials along relatively fastrnand controlled volume rate air injections. These high rates intend to give preference to single-phase air flowrnmechanisms associated with the opening of stress-dependent pathways. Particular attention has been focused onrnthe changes in the pore network to detect opening of fissures after air injection tests using mercury intrusionrnporosimetry. Selected experimental results have been simulated using a fully coupled hydro-mechanical finiternelement code, which incorporates an embedded fracture permeability model to account for the simulation of therngas flow along preferential pathways.