Objective Thermochemical sulfate reduction(TSR)is the reaction between anhydrite and petroleum fluids at elevated temperatures to produce H2S and CO_2.TSR has been studied in many sedimentary basins such as China’s Sichuan and Tarim basins because it has a profound impact on the commercial viability of petroleum Objective Thermochemical sulfate reduction (TSR) is the reaction between anhydrite and petroleum fluids at elevated temperatures to produce H2S and CO_2.TSR has been studied in many sedimentary basins such as China’s Sichuan and Tarim basins because it has profound impact on the commercial viability of petroleum