Designing a Current Injection Tool for Logging While Drilling

B. Oetiker[1], B. Friedman[1], and H.E. Hall Jr.[1]

[1]Department of Physics, Sam Houston State University, Huntsville, Texas, USA

High-resolution imaging is useful in oil and gas exploration to identify producing fractures that can be in the millimeter thickness range. In principle, high-resolution imaging maybe achieved using “current injection” to measure the electrical conductivity of the formation. Two current injection devices are compared for possible use as Logging While Drilling (LWD)imaging: The modified microlaterolog (MMLL) and the “short guard” (SG). Both the MMLL and SG in this work make use of a constant current source surrounded by an array of insulators and focusing current sources. The devices are readily and accurately modeled in three dimensions using COMSOL Multiphysics.