低渗透油藏合理关井测压时间的确定

DETERMINATION OF THE REASONABLE SHUT-IN PRESSURE MEASURING TIMES IN THE LOW-PERMERBILITY OIL RESERVOIR

为了提高试井解释参数的可靠性,减少因关井导致的产量损失,开展了低渗透油藏合理关井测压时间研究。依据压力恢复曲线,考虑井筒储集效应及表皮效应的影响给出常规关井时间的确定方法;考虑边界或供油半径对关井时间的影响,通过半对数曲线回归得到探测半径与关井时间的数学表达式。特低渗透油藏测试的合理关井时间确定方法:选取常规方法计算的合理关井时间及受邻井干扰时间两项中的最小值。利用该方法确定的合理关井测压时间可以有效指导试井方案实施,加深对低渗透油层动态特征认识。

In order to improve the reliability of well test interpretation and reduce the production lose due to the well shut-in,the researches on the reasonable pressure measuring time are conducted for the low-permeability oil reservoir.By means of the pressure buildup curve and considering the influences of the borehole storage and skin effects,the determing methods for conventional shut-in time are presented;in the consideration of the effects of the boundaries and oil drainage radius on the time,and moreover with the help of the semi-log plot regression,the mathematical expression between the investigation radius and shut-in time is obtained.The determining method of reasonable shut-in testing time in extra-low-permeability oil reservoirs shows as follows:to he is selecting the minimum value between the reasonable shut-in time from the conventional calculating methods and interferred time by the offset wells.The reasonable shut-in testing time by this method can provide the guide for the effective implementation of well test program and deepen the cognition of the performance characteristics of the low-permeability reservoir.