控制气井地层压降速度配产方法探讨

RESEARCH ON PRORATION METHOD FOR CONTROLLING RESERVOIR PRESSURE DESCENDING RATE

SX气藏是定容封闭弹性气驱气藏,气藏不出砂、产水量小且井底无积液。该气藏因生产任务繁重,各类试井资料缺乏,确定气井合理产量的资料依据不足,气井配产通常为无阻流量的1/5~1/3,生产实践表明,这种经验方法存在较大误差,部分气井产量低于无阻流量的1/5仍表现出地层压力下降快、稳产期短的特征。文章在气藏物质平衡方程基础上,提出了一种根据地层压力下降速度对气井进行配产的方法。该方法通过建立气井已知日产量、已知地层压降速度、合理地层压降速度和合理日产量之间的关系来求取气井的合理产量。应用实例表明,该方法简单易行,且准确度较高,可作为气井合理配产的参考依据。

Gas reservoir SX is a closed constant-volume,elastic gas driving reservoir. This reservoir is of no sand production,low water production,and no liquid accumulation at the well bottom. Due to the heavy production task,lack of varieties of well test data,no sufficient evidence was available for the decision of the reasonable proration. The proration was often one fifth to one third of the open flow according to the experience.However,the actual production indicated that the empirical method produced large errors at the proration. Some gas wells was producing lower than the one fifth of open flow,but the reservoir pressure still dropped severely with a short stable production period. Based on the material balance equation,this paper proposes a method to calculate the reasonable gas well proration according to formation pressure descending rate. The reasonable proration can be obtained by setting up the relationship between the known daily production,known formation pressure descending rate,the reasonable formation pressure descending rate and the reasonable daily output. The application shows that this method is simple and accurate. It can be used as the reference for gas well proration.