New Insights into the Origin of OSCs in Petroleum: A Chemical and Thermodynamic Analysis

摘要

Thermal simulation experiments on the reaction between n-C_8H_(18) and CaSO_4 were carried out under high temperatures and high pressures. Properties of the reaction products are characterized by advanced analytical methods. Based on the results of simulation experiments, possible reaction pathways and thermodynamic characteristics were tentatively investigated. It was found that n-C_8H_(18) can react with CaSO_4 to produce CaCO_3, H_2S, CO_2, H_2O, CS_2, and a series of organic sulfur compounds (OSCs). The conversion of elemental sulfur in the molecular structure of CaSO_4 to small molecule inorganic sulfides and thiophene sulfur increases with the increase of temperature. There is a strong thermodynamic drive for the reaction of n-C_8H_(18) with CaSO_4 and high temperature is favorable to the reaction. This study may provide new insights into the origin of OSCs in petroleum.