基于TMD工具箱海上油气井试井解释潮汐效应消除方法

Tidal effect elimination method in well testing interpretation of offshore oil and gas wells based on TMD toolbox

海上油气井压力测试过程中,潮汐效应产生的干扰压力会造成井底压力出现周期性波动,影响流态识别和储层物性参数解释的准确性。利用Tidal Modal Driver工具箱,实时预测海平面高度,基于压力恢复过程中的双对数函数,建立非线性最优化模型,采用Levenberg-Marquardt算法求解潮汐影响系数和相位差,消除井底压力测试数据中的潮汐效应影响。结果表明,原始数据经过TMD工具箱过滤潮汐效应后,压力曲线后期较平滑,压力导数曲线后期波动明显减少,地层渗流特征和边界特征比较明显,更加真实地反映了地层特征,矫正效果良好。该方法不需要测试海底压力数据作为参考信号,仅过滤掉潮汐信号,保留完整油藏信号,为矫正含有潮汐效应的井底压力测试数据提供了有效手段。

During the pressure test of offshore oil and gas wells,the interference pressure caused by tidal effect will cause periodic fluctuation of bottomhole pressure,which will affect the accuracy of flow pattern identification and reservoir physical parameter interpretation.In this paper,the tidal modal driver toolbox is used to predict the sea level height in real time.Based on the double logarithmic function in the pressure buildup process,a nonlinear optimization model is established.The Levenberg-Marquardt algorithm is used to calculate the tidal influence coefficient and phase difference,so as to eliminate the tidal effect in the bottomhole pressure test data.The results show that after filtered by TMD toolbox,the pressure curve of the original data is smoother in the later stage,and the fluctuation of pressure derivative curve is significantly reduced obviously in the later stage,which can accurately identify the characteristics of radial flow stage and later stage.This method does not need to test the seabed pressure as the reference signal,it only filters out the tidal signal and then retains the complete reservoir signal,which provides an effective means to correct the bottomhole pressure test data containing tidal effect.