An experimental investigation of the thermophysical properties of shale reservoirs: a case study of the Wufeng-Longmaxi formation in the Jiaoshiba Area

Abstract The production of shale oil and gas is increasingly recognized as being influenced by temperature fields. Hydraulic fracturing involves the injection of substantial amounts of fracturing fluid into the reservoir, which alters the temperature field distribution and, in turn, affects shale gas production. In this work, we study the shale formations of Longmaxi, analyzing the factors that affect the thermophysical properties of shale under normal pressures. Using Hot Disk equipment, thermophysical properties were measured and a thermal conductivity model for shale was formulated from such data. The results reveal that mineral composition, temperature, and bedding characteristics are the primary determinants of shale thermophysical properties, while no significant correlation was found for porosity, permeability, or water saturation. We also identified variations for two distinct temperature ranges, below and above 60°C, as each exhibited different rates of change in thermophysical properties. Notably, pronounced bedding leads to less uniform heat transfer within the reservoir. This study offers theoretical insights into predicting temperature changes during hydraulic fracturing, which may aid oil and gas production.