Correcting for Tool Decentralization of Oriented Six-Arm Caliper Logs for Determination of Contemporary Tectonic Stress Orientation

摘要

Tool decentralization is a major problem in the analysis of six-arm caliper data, particularly in highly deviated wells. It precludes accurate determination of borehole geometry and hence, interpretation of borehole volume, stratigraphic horizons and present-day stress orientation. We test four methods for correcting tool decentralization of six-arm caliper data, for the primary purpose of interpreting present-day stress orientations from borehole breakouts. The 'chord approach' and 'ellipse algorithm' yielded the most accurate corrections for tool decentralization in real and modeled scenarios of breakouts, key-seats and in-gauge holes.