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针对井地电位测量系统的正演数值模拟问题,首先介绍了该系统的正演基本理论,然后采用“镜像”法,推导了垂直有限长线电流源在无限大半均匀介质中任意深度时的正常电位解析式,并在此基础上,推导了相应的装置系数和混合边界条件公式.结合有限差分法,实现了正演模型的求解计算.数值模拟中,采用不同的正常电位公式,混合边界条件公式和装置系数公式,分别建立了均匀介质模型、高阻异常体模型和低阻异常体模型,并对异常体正演响应的异常特征和分布规律进行了对比分析.结果表明,所推导的公式模拟异常体电位响应更准确,为后续更精确的反演和解释现场测量数据奠定了基础.
Aiming at forward numerical simulation of well ground potential measurement system, firstly, the basic theory of forward modeling of the system is introduced, and then the “finite element” finite element current source is derived at arbitrary depth in an infinite semi-homogeneous medium Normal potential solution, and on this basis, derived the corresponding device coefficient and mixed boundary conditions formula. Combined with finite difference method, to achieve the forward modeling solution calculation. Numerical simulation, using different normal potential formula, mixed boundary Condition formula and device coefficient formula, the homogeneous medium model, the high resistance anomalous body model and the low resistance anomalous body model are respectively established, and the abnormal characteristics and distribution of the abnormal body forward response are compared and analyzed. The results show that the deduced The formula simulated abnormal body potential response is more accurate, which lays the foundation for the subsequent more accurate inversion and interpretation of field measurement data.