低渗气藏气水两相非达西渗流及产能影响因素分析

气水两相渗流是气藏开发过程中遇到的一个重要的问题。准确地研究气水两相渗流,对气井产能的影响有着非常重要的意义。针对开始产水的低渗透气藏,基于流体在地层中的多相渗流理论,建立数学模型,并对气水两相的渗流微分方程进行求解,推导出考虑非达西效应和表皮因子的气水两相产能公式。分析了不同水气比条件下,压力与拟压力的关系。实例计算结果表明,随着水气比的增大,气井的无阻流量不断减小,降低水气比对气藏开发有着重要意义。关于气水两相渗流机理及产能的分析,可以为产水气井的生产动态的分析提供指导。

Analysis of gas - water non - Darcy seepage and its influencing factors in low permeability gas reservoir

It is very important to study the effect of gas-water two-phase seepage on the gas well productivity in gas-water two-phase seepage flow, which is an important problem in gas reservoir development. Based on the theory of multi-phase percolation of fluids in the formation, a mathematical model is established to solve the seepage differential equation of gas-water two-phase flow. The non-Darcy effect and skin factor are deduced. Gas-water two-phase productivity formula, the relationship between pressure and pseudo-pressure under different water-vapor ratio conditions was analyzed. The calculated results show that with the increase of water - gas ratio, the open - flow of gas wells decreases, and the decrease of water - gas ratio is significant to gas reservoir development. The analysis of gas-water two-phase seepage mechanism and productivity can provide guidance for the analysis of gas-water production.