自适应高阶矢量有限元方法在随钻电阻率测井中的应用

Application of adaptive higher-order vector finite element method to simulate resistivity logging-while-drilling tool response

利用自适应高阶矢量有限元方法模拟不同模型仪器响应,分析随钻电阻率测井中井眼、源距、接收线圈之间的距离、线圈与地层之间的距离以及发射线圈长度等因素对仪器响应的影响。数值模拟结果表明:增大仪器的源距、减小接收线圈之间的距离或接收线圈贴近井壁位置,都有利于增强仪器在地层分界面处的分层能力,小井眼环境则有助于获得更加真实的仪器响应特征;与传统的自适应h方法相比,新方法具有计算精度高、求解速度快、误差指数速率收敛等优点。

An adaptive higher-order vector finite element method was used to simulate different models of instrument response. The main influence factors on resistivity responses including borehole, source distance, the distance between the receiving coil, the distance between coil and formation, the emitting coil length and other factors were analyzed. The numerical simulation results show that increasing the source distance, reducing the distance between the receiving coils or the distance between receiving coils and formation help to enhance the resolution ability of the instrument. The smaller borehole diameter is more helpful to obtain the real logging responses. Compared with the conventional adaptive h method, the new method has high accuracy, high speed of solving and the convergence of error exponent rate.