Application of a Non-Orthogonal Coordinate System to Inverse Single-Well211 Electromagnetic Logging Problem

摘要

Electromagnetic logging methods as known in the oil industry are methods for211u001edetermining the electrical conductivity distribution around a wellbore from the 211u001elow-frequency field measurements. When the well intersects the rock formation at 211u001ean arbitrary angle, a full-vector analysis is required to interpret the 211u001emeasurement results. Furthermore, the invasion zones and simultaneous layering 211u001ealso complicate the problem. In this study, we develop a robust inversion scheme 211u001ethat can interpret the measurement results in such configurations. To that end, 211u001ewe have modeled the dipping-bed environment using an oblique coordinate system. 211u001eBy formulating the problem in terms of an integral equation with an oblique 211u001ecoordinate system, we are able to avoid the use of staircase discretization grid 211u001eto model the dipping-bed environment.