低渗透气井试井解释渗透率异常现象分析

根据气井压降或压恢曲线解释的渗透率与测试产量的大小基本无关。但低渗透气井不同产量测试、修正等时试井"等时间隔"测试的压降或压恢曲线解释的渗透率随产气量的增大而降低,与通常的不稳定试井解释理论相悖。通过气井不稳定试井理论研究,结合矿场不稳定试井资料解释、分析,认为上述现象主要是由于气井工作制度不合理所引起。提出气井只有以合理工作制度测试,才能根据其压降、压恢曲线解释得到可靠的渗透率。这对气井试井及其解释工作起到重要指导作用。

Analysis of abnormal interpretation permeability in low-permeability gas well testing

Usually,it is believed that interpretation permeability from the pressure drop or pressure build-up curve of gas well is almost independent of testing production.However,the interpretation permeability of different production testing or modified isochronol testing of low-permeability gas well is decreasing with the gas production increasing.It is contrary to explains of the usual pressure transient testing theory.In this paper,by gas well transient testing theoretical study,together with data interpretation and analysis in mines transient testing, results that the above phenomenon was mainly due to the unreasonable working system of gas well.And presents that the reliable interpretation permeability can be get from the pressure drop or pressure build-up curve only when gas wells test under a reasonable working system.It has played an important guiding role in the gas well test and its interpretation work.