Abstract:

Some gas reservoirs with high H2S content have been found in northeast Sichuan in China, such as PuGuang gas field, Luojiazhai gas field and so on. In the course of development of the gas reservoirs with high H2S content, as formation pressure falls continually, elemental sulfur will precipitate from gas phase after running up to critical saturation state and deposit at reservoir pore space and throat, consequently resulting in formation porosity and permeability reduction; gas well production halts when it becomes severe. Gas reservoirs with high H2S content sulfur deposition prediction model is set up according to dissolution mechanism of sulfur in nature gas and material balance theory and the Luo7 well taken as an example to forecast sulfurbearing saturation in different pressure range, as well as effect of sulfur deposition on production rate. Achievements show that，when gas reservoir pressure drops down to 40 MPa ，production rate falls by 82.5％;reservoir pressure drops down to 37 MPa，gas well production will halts.

Key words: gas reservoirs with high H2S content, solubility experiment, sulfur deposition, model, Luojiazhai