含硫气井非达西渗流下的产能预测方法

The productivity prediction method under non-Darcy flow for sulfur gas wells

含硫气藏在开发过程中,固态硫沉积将降低储层岩石孔隙度和渗透率,极大地破坏气井产能,此时常规气井产能计算模型已经不再适用,因此建立含硫气井产能预测模型十分重要。本文考虑硫元素在近井地带沉积引起的储层渗透率变化,将储层分为沉积区和非沉积区。基于渗流力学理论,建立了含硫气藏直井、水平井在平面径向非达西稳定渗流条件下的二次三项式产能方程。通过分析硫沉积、启动压力梯度、水平段长度对气井产能的影响,认为气井产能随硫沉积饱和度的增大而减小,无阻流量与启动压力梯度呈负相关关系,水平井段长度越长,产能越大。

As the development of sour gas reservoir ,sulfur deposition will reduce the porosity and permeability of the reservoir rock ,and greatly destroy the productivity of gas wells .The conventional gas well deliverability calculation model is no longer applicable ,so the establishment of sulfur gas wells productivity prediction model is very important .In this paper ,considering the change of reservoir permeability in the near wellbore zone caused by elemental sulfur deposition ,the reservoir can be divided into deposition region and non deposition region .Based on the theory of fluid mechanics ,establish the quadratic trinomial deliverability equation in radial steady non‐Darcy seepage of vertical and horizontal wells in sour gas reservoir .Through the analysis of the impact of sulfur deposition ,the starting pressure gradient , horizontal section length on gas well inflow performance ,we think the gas well productivity decreases with the increase of sulfur saturation ,open flow capacity is negatively correlated with the starting pressure gradient and the productivity is larger with the longer horizontal section length .