Experimental Investigation of Infilled-Shear Fractures Conductivity in Shale Reservoirs

Abstract The study and assessment of flow conductivity within infilled-shear fractures play a pivotal role in guiding the development of shale gas resources. This paper presents an investigation using shale reservoir rock samples from the Longmaxi Formation. We employed a novel infilled-shear seepage coupling experimental system, developed in-house, to perform nitrogen flow tests under stress seepage coupling conditions. Our findings reveal that the incorporation of proppants mitigates the impact of fracture roughness, and the effect of fracture morphology on conductivity is primarily evident at lower concentrations. The impact of shear slip on flow conductivity is discernible only in rock samples with higher roughness. Furthermore, the evolution of infilled-shear fracture conductivity with increasing proppant concentration follows a biphasic pattern: an initial decrease followed by an increase. Intriguingly, a significant positive correlation exists between the critical proppant concentration and the volume capacity, with an approximate threshold of 25%. This correlation is of profound importance for the strategic planning of fracturing operations.