一种改进的非均质底水气藏水平井产出动态预测方法

An improved production performance prediction method for horizontal wells in heterogeneous bottom water gas reservoirs

未考虑渗透率非均质性及井筒附近非达西效应的影响时,底水气藏水平井产出动态预测方法难以确定储层非均质性和气井位置对产能和见水时间的影响。在镜像反映和势函数的叠加原理基础上,考虑非均质、非达西效应和气-水界面抬升等因素的影响,提出了水平井井筒见水时间及产出剖面预测模型。模拟结果表明,底水气藏水平井的产能受渗透率非均质性和井筒位置的影响,不考虑非均质拟表皮的影响,将导致产气剖面偏高,非均质性越强产量越低;垂向渗透率越大更有利于提高气井产气量,而垂向渗透率越小、水平渗透率越大,越利于控制底水脊进;无因次避水高度越大,水平井见水时间越长,水平井生产初期底水脊进速度相对比较均匀,后期将急速上升。改进的预测方法对底水气藏水平井的开发具有一定的指导意义。

Without considering the influence of permeability heterogeneity and non-Darcy effect near the wellbore,the production performance prediction method of horizontal wells in bottom water gas reservoir is difficult to determine the influence of reservoir heterogeneity and gas well location on productivity and water breakthrough time.Based on the superposition principle of mirror reflection and potential function,considering the influence of heterogeneity,non-Darcy effect and gas-water interface lifting,a prediction model of water breakthrough time and production profile of horizontal well wellbore is proposed.The simulation results show that the productivity of horizontal wells in bottom water gas reservoir is affected by permeability heterogeneity and wellbore location.If the influence of heterogeneous pseudo skin is not considered,the gas production profile will be higher,and the stronger the heterogeneity,the lower the production.The larger the vertical permeability is,the more favorable it is to improve the gas production of the gas well,while the smaller the vertical permeability is and the larger the horizontal permeability is,the more favorable it is to control the ridging of bottom water;The larger the dimensionless water avoidance height is,the longer the water breakthrough time of the horizontal well is.At the initial stage of horizontal well production,the bottom water ridge velocity is relatively uniform,and will rise rapidly in the later stage.The improved prediction method has certain guiding significance for the development of horizontal wells in bottom water gas reservoirs.