基于高精度自适应hp-FEM的随钻电阻率测井电场数值模拟

Numerical Simulation of Electric Field in Resistivity LWD Using High Accuracy Self-Adaptive hp-FEM

采用高精度自适应hp有限元(FEM)算法对随钻电阻率测井电场分布情况进行模拟,能够根据地层模型的实际情况和误差指示自动选择合适的细化方式和计算策略,不需要对整个求解域进行计算就能使有用信号呈指数速率准确地收敛到其真值附近.计算结果显示,获得的接收线圈感应电动势的相位差和幅度比曲线和地层分层情况吻合较好,有助于实际随钻电阻率测井资料的解释.

A high accuracy self-adaptive hp-finite element method（FEM） is used to simulate resistivity logging-while-drilling（LWD） electric field distribution.The algorithm can choose optimal refinement and calculation strategy according to practical formation model and error estimation.Accurate approximations of electrical field can be obtained without an accurate solution in the entire computational domain.Self-adaptive hp-FEM method has an exponential convergence rate.It indicates that voltage phase difference and amplitude ratio curves between receiver coils are well matched with the layer model.It is helpful to interpretate resistivity LWD data.