产水致密气井动态储量评价新方法

A New Technique of Reserve Estimation in Water-production Tight Gas Wells

针对层内水来源的产水气井动态储量评价,分析了现有动态储量评价方法在产水致密气井中的适应性,对比了不同水气比现有方法计算误差,在此基础上,建立了层内水来源的产水气井气水两相流流动物质平衡方程,形成了此类井动态储量求解流程,并运用理论模拟方法对新方法及流程进行验证。结果表明:层内水产出对气井储量评价特征曲线形态影响较小,但对储量计算结果具有一定影响;当水气比小于5 m^(3)/10^(4) m^(3),相对误差约5%,认为现有方法仍适用,但大于该值则不适用;新方法能有效减小误差,经验证,水气比11 m^(3)/10^(4) m^(3)时误差在1.4%,能够满足工程应用的需要。所提方法应用于鄂尔多斯盆地东缘临兴区块,为该区产能准确认识、井距优化部署提供了新方法。

For the water-production tight gas wells in which the flowing water is internal water in formation while not edge and bottom water,the applicability of current reserve estimation techniques were analyzed,and the calculation errors of existing methods with different water-gas ratios(WGR)were compared.Based on this,a new flowing material balance equation considered the internal water-gas two phase flow was established,and a procedure was proposed.This new technique was validated using the theoretical modeling and showed good results.The results show that the water-production has little effect on the specialized curves of reserve estimation,while has certain effect on the results of reserve estimation.When the WGR is lower than 5 m^(3)/10^(4)m^(3),the relative error is less than 5%,the current techniques can be used in this kind of gas wells.Conversely,the opposite is true.The new established technique can decrease the error and the error for example of WGR equals 11 m^(3)/10^(4)m^(3) is decreased to 1.4%.The proposed method was applied in Linxing area in east Ordos Basin,which provides a new method for accurateunderstanding of productivity and optimal deployment of well spacing in this area.