广义二项式产能方程的推导与应用

摘要

The traditional binomial productivity equation has a negative slope when dealing with high productivity gas wells in the western South China Sea,and the main reason for the analysis is that the change of formation pressure during the test is neglected.Starting from the formation pressure response during gas well test,and combining the material balance equation,the effective average formation pressure during the test period is derived.Furthermore,the regression method of generalized binomial productivity equation which considers the change of formation pressure in different test stages is proposed.Application shows that the error of absolute open flow capacity between the proposed method and the well test is no more than 10％ for high productivity gas wells.For common gas wells,the error of absolute open flow capacity between the proposed generalized binomial equation and the traditional binomial equation is less than 5 ％.This method provides a solution to the abnormal production correction of high productivity gas wells.%利用传统二项式产能方程对南海西部气田多口高产气井回归时出现了产能方程斜率负异常现象,分析认为主要原因是回归时忽略了测试过程中地层压力的变化.从气井测试过程中地层压力响应入手,结合物质平衡方程,推导得到了测试期间动用范围内的有效平均地层压力,进而提出了气井广义二项式产能方程回归方法,回归时考虑了不同测试阶段地层压力的变化,以弥补传统方法对地层压力简化处理带来的误差.实例应用表明,对于高产气井,本文方法与试井设计法所得气井无阻流量值处于同一数量级,误差不超过10％;对于常规气井,本文方法与传统二项式产能方程回归方法所得气井无阻流量误差在5％以内.本文方法为高产气井产能异常矫正提供了解决思路.