Orthotropic Horizontal Stress Characterization from Logging and Core-Derived Acoustic Anisotropies
Baker Hughes, Argentina
This study provides the analytical solution of the two horizontal principal stresses for orthotropic rocks with horizontal laminations or thin beds and vertical natural fractures in term of six elastic properties; three Young’s modulus and three Poisson’s ratios. An analytical workflow is introduced for combining and complementing both borehole acoustic anisotropies (azimuthal and transverse shear wave anisotropies) with ultrasonic core measurements to fully characterize the stiffness tensor of an orthotropic formation. The discrepancies between diverse anisotropic rock models are discussed and presented with case stories from US unconventional shale plays. The resulted horizontal stresses will require tectonic strain calibration from minifracs, straddle packer microfrac testing and/or borehole failure evidences such as breakouts or induced fractures observed on image logs.
AAPG Search and Discovery Article #90165©AAPG 2012 GEOSCIENCE TECHNOLOGY WORKSHOP, 2-4 December 2012, Buenos Aires, Argentina