试井解释中导数曲线超越压差曲线的原因分析

Analysis of Reason for Derivative Curve Overpassing Pressure Difference Curve in Well Testing Interpretation

试井解释时有时发现,整个测试过程是成功的,没有任何失误,但依据测试的数据得到的压力导数曲线的形态却发生扭曲变形,甚至出现导数曲线超越压力曲线的情况,不能用于解释并计算相关参数。对生产井和探井试井解释分析认为,关井前的开井时间长短是引起这种现象的原因之一。建议确定真实的开井时间和开井产量,对于低渗、特低渗,不建议使用一关数据解释等。

In well test interpretation,although the whole testing operation is successful,and any mistake is occurs,the shape of gained pressure derivative curve from the tested data is abnormal in some cases,those are crucial to calculate the formation parameters. According to analyzing producing well and exploration well respectively,The length time of opening well before shut-in is probably one of the reasonsthat causes this phenomenon,and for the low and super low permeability reservoirs,the first closing well data does not recommend to be used.