Effect of sulphur deposition on well performance in a sour gas reservoir

Abstract

AbstractSulphur deposition has been the centre of attention in sour gas reservoir development. While Roberts's solubility model is widely used in sour reservoir damage to describe elemental sulphur precipitation and deposition in a near‐wellbore area, this model cannot accurately predict a change in sulphur solubility. A productivity prediction model, with consideration of sulphur deposition, is also not complete, particularly for modelling sulphur deposition and fractured horizontal wells. In this study, based on the unsteady percolation mechanics theory and superposition principle, we develop a new numerical model to quantify fractured horizontal well production by combining various sulphur solubility models. We examine the effects of sulphur deposition on permeability, porosity, and production performance. The results show that sulphur deposition damages reservoirs and thus decreases well production in later stages. These results also show that the permeability and porosity reduction using Roberts's sulphur solubility model is greater than that using Hu et al.'s sulphur solubility model. The damage degree is relatively smaller when using Hu et al.'s sulphur solubility model, and the effect of sulphur deposition on a production performance curve is negligible. Moreover, Hu et al.'s model is closer to actual production data. The results can guide reservoir engineers to optimize development plans in sour gas reservoirs.