Insights into the Transformation Patterns of Overmature, Organic-Rich Shale Reservoirs under High-Temperature Conditions: Evidence from Physical Experiments

HIGHLIGHTS (1) Using combined low-temperature gas adsorption and high-pressure mercury intrusion porosimetry, the effect of high-temperature treatment on the porosity of overmature shale was investigated. (2) The porosity, specific surface area, and fractal dimension of pores in overmature shale exhibit multistage variations with temperature. (3) The optimal transformation temperature for shale lies within the 500–600℃ range.