During the development of gas reservoirs with aquifers,reservoir pressure decreases gradually with gas production,and edge and bottom water will cone into gas reservoirs.In the early stage of water invasion,waterflood front is relatively far from bottom hole.If the aquifer is distributed uniformly,the waterflood front can advance stably,at the moment the driving effect of aquifer can replenish energy for gas reservoirs,allowing the average gas reservoir pressure drop to slow down and gas production to be maintained.In the middle-late stage of water invasion,gas wells will be watered out rapidly and wellbore liquid loading will seriously impact gas production.Therefore,the analysis of water invasion performance and obtaining of water invasion time,aquifer size and water influx at each time point are of great significance for developing gas reservoirs with aquifer.Iterative solution is made by combining material balance equation for water-drive gas reservoir and pseudo-steady state water invasion equation.Finally,by using C# programming language,parameters including dynamic reserves of gas reservoir,aquifer size,and water invasion rate and cumulative water influx at each time point can be determined on the basis of production data matching in gas wells.The established numerical simulation model for gas reservoirs verifies that the method is reliable and applicable in field,and can get results rapidly with small error.The numerical simulation results directly show the validity of the water influx evaluation.%在开发含边底水气藏的过程中,随着气体的采出,气藏压力逐渐降低,边底水会侵入气藏.在水侵初期阶段,由于水驱前缘距离井底较远,若水体分布较均匀,水驱前缘会较稳定驱进,此时水体的驱动作用补充了气藏的能量,使气藏的平均压力下降变缓,维持了气井的产气量.当气藏进入水侵中后期阶段,气井迅速水淹,井筒积液将严重影响产气.因此,分析气井的水侵动态,获得水侵发生的时间、水体规模以及各时间的水侵量对于开发含边底水气藏具有重要的意义.通过水驱气藏物质平衡方程与拟稳态水侵方程的结合进行迭代求解,运用C#编程语言,最终可根据气井生产数据拟合确定气藏动态储量、水体规模以及各时间的水侵速度、累计水侵量等参数.通过建立的气藏数值模拟机理模型,验证了本文方法的可靠性、矿场适用性以及获得结果的迅速性,本文方法计算结果误差较小,数值模拟结果直观展示了水侵量评价的正确性.
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