气井测试一点求绝对无阻流量方法局限性研究

Study on limitation of one-point method to get absolute open flow in gas well test

气井测试一点求绝对无阻流量方法(简称一点法)来源于二项式、指数式渗流方程。一点法把二项式对比系数Ad、指数式指数n固定为常数,与其是产层渗流参数的函数这一科学基础是不相容的,因而所求得的气井绝对无阻流量不准确,用一点法数据推出的气井渗流方程也不可靠。对一点法的误差进行了分析表明,一点法只能用在不具备多点法稳定测试条件、避免大量气体放空损失的情况下初步估算气井绝对无阻流量。

The one-point method to get absolute open flow(AOF) in gas well test originates from binomial flow equation and exponential flow equation.The method sets the contrast factor Ad in binomial flow equation and the exponent n in exponential flow equation as constants.This is not consistent with the scientific basis that they are functions of reservoir seepage parameters,so that the gas well AOF thus derived is not reliable,neither is the gas well seepage equation derived from the data of one-point method.Error analysis of one-point method indicates that the method can only be used to estimate gas well AOF when multi-point stable test condition is unavailable and to avoid large amount of gas blow-down loss.