考虑启动压力梯度和压敏效应的超深层气藏产能方程的建立

超深层气藏一般具有低渗的特征,因而存在启动压力梯度;与此同时,储层岩石渗透率亦随气藏压力或有效覆压的变化而改变.以达西公式为基础,并综合考虑启动压力梯度和压敏效应对超深层气藏渗流规律的影响,建立了新的产能方程.应用于实际气藏计算,结果表明:仅考虑压敏效应或启动压力梯度时气井产能有所下降;当综合考虑这2种因素时,气井产量...

Establishment of productivity equation for ultra-deep gas reservoirs considering threshold pressure gradient and pressure-sensitive effect

Ultra-deep gas reservoirs generally have low-permeability characteristics,so there will be threshold pressure gradient.Meanwhile,the permeability of reservoir rock changes as the gas reservoir pressure or effective overburden pressure changes.Therefore,based on Darcy′s formula and considering the influence of threshold pressure gradient and pressure-sensitive effect on the seepage law of ultra-deep gas reservoir,this paper established a new productivity equation.The established equation was used in a gas reservoir.The calculation result shows that the production of gas well decreased when considering the threshold pressure gradient and pressure-sensitive effect of gas reservoir.When considering one of two effects,the production of the gas well decreased even more and the ratio of the AOF(absolute open flow) is about 71.44% of that when neglecting these two effects.This study also shows that the threshold pressure gradient and pressure-sensitive effect can not be ignored when examining the seepage law and inflowing performance of ultra-deep gas reservoir.This study is significant to deeply understand the productivity,predict the production performance and the recovery factor of ultra-deep gas reservoir.