异常高压下气井产量递减分析方法的应用

Production Decline Analysis for Gas Well with Abnormal Pressure

确定气藏参数的方法常常是关井测压。然而,我国有许多气藏渗透率特别低,压力恢复所需时间特别长,有时长达几个月。因此,有必要研究根据气井生产史确定气藏参数的方法,避免关井给生产带来的损失。对具有生产记录的气井,可以采用现代产量递减分析方法反求地层参数,并用标准化时间和标准化压力半对数图,作为检验计算结果正确与否的标准。实例对比表明,对于没有关井测压的气井,可以用该方法反求气藏参数。

Shut-in pressure survey is the conventional method for determination of gas reservoir parameters. For extra-low permeability gas reservoir, the time for pressure buildup is normally long, sometimes lasts several months. So it is necessary to do it based on the gas well production history so as to avoid economic loss caused by the shut-in. For wells with production history, the modern production decline analysis can be applied to yielding the formation parameters, and the semi-log figure of normalized time vs. normalized pressure is taken as the criterion to validate the calculated results. Case correlation study shows that for gas wells without shut-in pressure survey, this method can be used to resolve the reservoir parameters.