基于广义等效CR模型的地井、井地激电2.5维异常响应分析

摘要

When electromagnetic effects ignored at low frequencies,this paper achieves 2.5-dimensional surface-to-borehole,borehole-to-surface complex finite volume resistivity based on induced polarization (GEMTIP) model of generalized effective mediumin frequency domain.Firstly,according to the boundary value satisfied by surface-to-borehole and borehole-to-surface we introduce GEMTIP to geoelectric model and derive the discrete equations of finite volume,by utilizing preprocess iterative algorithm to solve the large and sparse linear equations.Comparisons numerical solution with analytical solution of two-phase layers show the validity of this algorithm.Finally,several multiphase models can test approach.Calculated field values are obviously distributed within a certain frequency bands.The results indicate that surface-to-borehole and borehole-to-surface devices are effective for detecting the abnormal body based on GEMTIP model and provide more new ideas for induced polarization measurements of wells.%在频率较低和忽略电磁效应的情况下,利用广义等效介质激电(GE MTIP)模型,实现了一种频率域中地井、井地2.5维复电阻率有限体积正演计算方法.从地井、井地电位满足的边值问题出发,将GEMTIP模型的频率响应引入到地电模型中,推导出有限体积各控制容积所满足的离散方程式;利用预处理迭代算法对大型稀疏线性方程组进行求解,通过对比两层大地模型的数值解与解析解,验证该算法的正确性;最后构建若干个典型多相态复合地电模型进行试算,并且在一定频段内计算所得场值异常分布明显.结果表明,联合地井、井地装置对基于GEMTIP模型的异常体探测是有效的.