An evaluation index for the fracturing effect in shale based on laboratory testing

It is clear that evaluating the fracturing effect with laboratory tests can shed some light on designing fracturing programs for shale gas exploitation. To evaluate the fracturing effect quantitatively, a series of uniaxial cyclic loading tests on shale were conducted. Based on the experimental results, a damage variable derived from the total axial strains of the loading–unloading cycles was established and introduced into a damage evolution...