Gerald Minerbo

Inductive conductivity tensor measurement for flowline or material samples

Present-day galvanic-based electrical conductivity measurements are hampered by limitations and necessary corrections, especially in the domain of geological core analysis. Low-accuracy techniques such as crucible, two-electrode, and four-electrode are constricted by current-path requirements, while high-accuracy techniques are time consuming and have limited domains of applicability. We present a novel apparatus capable of electrical conductivity tensor measurements in a noninvasive, noncontact, inductive manner with resolution from 5 mS/m. Inspired by the triaxial induction logging technology appearing in the oil patch today, our apparatus is naturally applicable in a novel way not only to anisotropic geological core analysis but also to arbitrary material samples and flowline systems.

Triaxial induction tool with electrode sleeve: A study of its response to borehole eccentricity

We developed a finite difference (FD) code to model the response of a multiple-spacing triaxial array induction tool with a multiple-electrode type sleeve in a homogeneous medium and decentralized within a borehole in a homogeneous medium. The electrode sleeve reduces the response of the transverse couplings to eccentering in a conductive borehole. The model response was carefully checked for grid refinement, while attempting to minimize run time. Many details of the electrode sleeve geometry were studied, using this code, which led to the final electrode sleeve design. The comparison between the FD code and two other independent codes is quantitative. Good agreement is found between measurements and calculations.