用不稳定流动的压力和流量解释致密低渗气藏的地层参数

Applying the non-stabilized flowing pressure and rate to Interpret low permeability tight gas reservoir parameters

针对致密低渗气藏关井压力恢复很难达到径向流的特点,利用致密低渗气藏开井过程中气体的不稳定流动方程,推导出不稳定流动系数at与时间t的线性函数关系,结合修正等时测试不稳定流动段的井底流压数据,用最小二乘法分别计算出at和b,再利用直线段的斜率计算地层系数Kh和惯性系数D,利用同一直线段的截距计算气井开井的表皮系数S。通过大牛地气田几口井的实际测试数据进行解释表明,该方法可以用于现场解释。

The buildup pressure is hardly to approach the radial flow state in low permeability tight gas reservoirs. By applying non-stabilized flowing equation from opening gas well of tight gas reservoir, relationship between non-stabilized factor at and time factor t is-developed, which are calculated by transient down-hole flowing pressure during modified Isochronal test with least-squares method. The parameters Kh and D are calculated by the slope of straight line regressed, and skin factor S is calculated by intercept of the same straight line. Calculation results of some wells in Daniudi gas field show that this method can be used to interpret tight gas reservoir parameter.