Gas-well water breakthrough time prediction model for high-sulfur gas reservoirs considering sulfur deposition

摘要

The sulfur-solubility decreases as a result of the decrease in gas reservoir pressure, leading to the solid-phase sulfur deposition. As a consequence, both the reservoir porosity and permeability decrease, subsequently influencing gas well water breakthrough time (GWWBT) in high sulfur gas reservoirs (HSGRs) with edge/bottom water. To acquire the value of GWWBT, a GWWBT prediction model for HSGRs should be established while taking into account sulfur deposition. Accordingly, based on gas Non-Darcy seepage law and sulfur deposition theory in porous media, a novel GWWBT in high sulfur gas reservoir with bottom water was developed in this study. The effect of dynamic factors (e.g., sulfur deposition, gas Non-Darcy flow, irreducible water saturation, and residual gas saturation) on GWWBT was involved in this model. The GWWBT was calculated via the proposed method and three classical models in five field basic parameters, and was compared with five filed values, respectively. This result indicates that the calculation of proposed method is in closer agreement with the field production data, and illustrates that the new proposed model is more reliable. In addition, the influence of dynamic factors was further discussed in detail by this proposed model.