Research on the initiation mechanism of thermochemical sulfate reduction (TSR).
硫酸盐热化学还原作用的启动机制研究

Thermochemical sulfate reduction (TSR), which includes a series of complex chemical reactions involving hydrocarbons, water and rocks in sedimentary basins, is an important reason leading to the occurrence and accumulation of natural gas with high hydrogen sulfide content, the acidification and corrosion of carbonate reservoir. In this paper, we try to elucidate the initiation mechanism and the controlling factors for TSR under gold-tube pyrolysis. By hydrous pyrolysis of oil with various inorganic salts (including chlorides and sulfides), it was attested that the presence of sulfate should be the essential factor for initiating TSR, MgSO4 will be more effective for the onset of TSR relative to CaSO4 and Na2SO4, the generation rate of H2S can be accelerated with the increase of salinity of the solution in MgSO4 system. Meanwhile, the experiments results indicated that TSR reaction rate is positive with the ionic strength of solutions, while weak acid conditions were demonstrated to be hard to initiate TSR. High content of organic labile sulfur compounds will avail the occurrence of TSR, saturated paraffin, especially those with larger-weight, are easier to be oxidated by sulfate relative to other groups in crude oils.