Forecasting H2S Production Risk in Thermal Projects for EOR

In petroleum industry, steam injection is commonly used as a thermal EOR method for heavy oil extraction. These processes are associated with chemical reactions occurring in the reservoirs, called aquathermolysis, which produce carbon dioxide (CO2) and H2S. Hence it needs to be given a particular attention when it is produced at the surface. To manage the risk of H2S production in thermal projects, the reservoir simulation including aquathermolysis reactions is a valuable asset. In this paper, we present a workflow combining experimental aquathermolysis with sulfur balance and reservoir numerical modeling. This workflow allows forecasting H2S production and oil composition in thermal projects. This paper focuses on presenting the three stages of the workflow . The first stage consists in a rapid localization of the reservoir areas that are prone to generate H2S, based on sulfur screening with the Rock-Eval Sulfur. The second stage consists in aquathermolyse experiments aiming at reproducing the chemical reactions that occur in the reservoir, and quantifying H2S yield as a function of time, temperature and reservoir properties. The third stage consists in reservoir simulation using an aquathermolysis kinetic model calibrated with the experimental data obtained on stage 2.