Ultrasonic velocity measurement of sidewall cores for different stress paths

Integration of geomechanics test results with well log measurements is a crucial step in developing geomechanical models to estimate in situ stress state, maintaining stable wellbore and design hydraulic fracture. Limited availability of core material severely restricts design of a comprehensive geomechanics test program. Sidewall core plugs, although easier to obtain than conventional cores, suffer from being short relative to the length to diameter ratio specified by ASTM. This paper presents a solution to overcome size issues related via measuring ultrasonic velocity on sidewall core plugs at various stress paths. A unique experimental setup allows measurement of ultrasonic velocity both parallel and perpendicular to bedding. The results were then compared with velocity measurements obtained from sonic logs. It was observed that velocity measured within an isostatic stress path provides the closest match to log velocities, thus increasing confidence in dynamic geomechanics measurements on sidewall plugs and allowing geoscientists and engineers with low budgets to conduct more comprehensive geomechanics analyses.