Numerical Simulation and Parameter Analysis of Rescue Well Distance Measurement

Refining the accuracy of active magnetic ranging systems through injected current methodology represents a critical engineering challenge for enhancing inter-well communication reliability in subsurface rescue operations. This study seeks to refine the accuracy of an active magnetic ranging system utilizing injected current. A three-dimensional finite element numerical simulation approach is employed to systematically examine the current density distribution under multi-medium coupling conditions. By formulating a current field control model based on Laplace equation and a boundary condition constraint system, a three-dimensional numerical calculation model of the electric field and current density distribution within the accident well casing is developed, with a focus on the sensitivity analysis of key parameters. Numerical experiments reveal that the potential field on the casing surface and the axial current density exhibit significant spatial non-uniformity, their distribution governed by the coupling effects of excitation current intensity, well spacing, casing and intrusion conductivity, and geometric dimensions. Specifically, localized casing corrosion or damage induces a step change in electric field strength, without causing significant distortion of current distribution. Under multiple casing parallel operation, the electric field and current signals of the target casing remain detectable, although their effective amplitudes demonstrate significant attenuation. The innovation of this work lies in the integration of high-fidelity 3D numerical simulation with systematic sensitivity analysis, providing a theoretical foundation and practical guidance for optimizing excitation parameters and improving anomaly recognition in magnetic guidance systems for rescue well operations.