Modeling productivity of horizontal wells in a high sulfur gas reservoir: Consideration of the impact of porosity reduction by sulfur deposition

As pressure in a high sulfur gas reservoir drops during the development process, deposition of elemental sulfur in pores results in a decrease in porosity and permeability, which ultimately has an adverse effect on gas production.Using the relationship between element sulfur solubility and pressure, in tandem withthe theory of gas stable seepage,a mathematical model that explainselemental sulfur precipitation can be established. The model can befurther used to establish a horizontal well pseudo pressure productivity model, hichconsidersthe effect of sulfur deposition on permeability in a high sulfur gas reservoir.According to the field case study presented herein, use of the new model equationproduces a result that approximates the actual wellproductivity, which means that this model canbe used as apredictive tool for estimating productivity of a high sulfur gas reservoir that isbeing developed using horizontal wells.