异常高压气藏产能测试分析方法

南海西部海域莺歌海盆地DFX气田埋深3 000 m,压力系数1.8,地层压力52.7 MPa,为异常高压气藏。目前该区域第一口探井DFX-1井的稳定产能测试资料出现二项式产能方程回归曲线斜率为负,指数式产能方程的指数大于1的异常情况,无法计算气井无阻流量。针对其异常情况,采用了"一点法"、产能方程校正、考虑表皮影响的拟压力产能方程以及考虑应力敏感影响的改进的拟压力产能方程等多种方法,计算异常高压气井的无阻流量。并对比分析"一点法"、产能方程校正的不足,提出考虑表皮影响的拟压力产能方程,能有效计算出合理的异常高压气井无阻流量。同时,采用改进的拟压力方法证实渗透率应力敏感给单井产能带来的影响不容忽视。

ANALYSIS METHOD OF THE ABNORMAL PRODUCTIVITY TEST IN ABNORMALLY HIGH PRESSURE GAS RESERVOIRS

The stable production capacity test data of Ying-gehai basin DFX-1 well is abnormal: The binomial deliverability equation regression curve slope is negative,the exponential productivity equation index greater than 1,which can not be calculated absolute open flow. Using the single point,the corrected deliverability equation, the pseudo pressure deliverability equation considering the effects of rate skin factor and the modified pseudo pressure deliverability equation considering the effects of stress sensitivity to calculate absolute open flow potential of the abnormal high pressure gas wells. By analysed comparison of various deliverability equation, the modified pseudo pressure deliverability equation considering the effects of rate skin factor can reasonable calculate absolute open flow potential of the abnormal high pressure gas wells. And it can not be ignored that permeability stress sensitivity to the impact of single well production, proved by the modified pseudo pressure deliverability equation