新型小型压裂摩阻测试方法的应用

Application of New Mini-Frac Friction Pressure Testing Technique to Gas Wells

在某油田两口气井进行的压前小型压裂测试中,由于测得近井摩阻较高,采取了补孔的方式降低摩阻。虽然压裂作业取得了成功,但是作业成本明显升高。压后分析认为,近井摩阻过高的原因可能是由于测试压裂注入液量较小,无法有效驱替近井地带孔隙空间内的天然气,最终在该处形成气液两相流导致摩阻测量值偏高。对压裂摩阻进行了理论分析,采用了一种新的、可以消除这种两相流干扰的测试压裂摩阻的方法,并在多口井中进行了应用,能够消除干扰值85%以上,从而大幅降低了施工时间和施工费用。

Because the near wellbore friction pressures were very high in pre-frac mini fracturing tests in two gas wells in an oilfield,reperforations were then conducted to reduce the high friction pressure.The well jobs were successful,but the operation costs were high.The post-frac analysis showed that the amounts of the fracturing fluid pumped in such pre-frac mini fracturing tests were too small to effectively displace gas and thus causing gas-liquid two phase flow in the near wellbore pore spaces,which accounted for the high friction pressures.This paper presents the theoretical analysis of the fracturing friction pressures and proposed a new mini-frac method.Application of it to many wells indicate that such two-phase flow interference can be removed by over 85%,hence,the operation time and costs have been reduced greatly.