Enhanced In-Situ Stress Profiling With Microfracture, Core, and Sonic-Logging Data

Abstract

Summary Knowledge of in-situ stress distribution, especially in the vertical direction, is vital to hydraulic-fracture geometry calculations. The microfracturing technique is recognized as the best method to measure in-situ stress directly. The technique, however, is typically limited to very few measurements and, at times, it is impractical to break down and measure in-situ stress in bounding nonproducing layers. Also, in layers with significant stress variation, microfracture measurements can be reflective of an average value of the variations and thus can be misleading. Alternative techniques like core measurements can suffer from depth discrepancies and lack of measurements at in-situ conditions. Sonic-logging methods can provide continuous in-situ measurements of rock mechanical properties; however, modeling stresses from mechanical properties have certain limitations. In this paper, we present a method that can compensate for the disadvantages of the individual techniques with the advantages of the others and thereby create relationships that can facilitate obtaining representative and continuous in-situ stress data. Data from two wells are presented to illustrate the method's application.