Sulfur deposition in the formation, the vicinity of the wellbore and the production line, may significantly reduce the inflow performance of sour gas wells and increase operation cost. The work of sulfur deposition prediction and removal are increasingly performing in sour natural gas reservoirs of South China. In this paper, a gas-liquid-solid mathematical model to predict sulfur deposition, has been developed based on the characteristics of composition and phase behavior of gasliquid system. i.e., the phase behavior of gas-liquid system is calculated in light of EOS, and the elemental sulfur is considered as a non-ideal solid described by virtue of regular solution theory. The EOS-related mathematical model proved to successfully match and predict sulfur deposition via some test examples. In addition, two formulated desulphuring agents of sulphone-amine solution and MDEA reinforcing solution are presented based on the solubility of H2S, CO2 and their mixture in water. The influences of operation conditions and other factors on desulphuring agents were investigated through both indoor and industrial experiments, and the results indicated that these two formulated desulphuring agents could effectively increase the rate of removing sulfur and also overcome the problems encountered during microbial oxidation of removing sulfides. The preliminary work can help engineer evaluate accurately sulfur deposition and remove effectively sulfides so that the impact of sulfur deposition on gas production is minimized during the development of sour natural gas reservoirs.
