ACOUSTIC ANISOTROPY CHARACTERIZATION OF WOODFORD SHALE AND ITS IMPACT ON HYDRAHULIC FRACTURING: NUMERICAL SIMULATION OF FRACTURES

Most materials show an anisotropic and heterogeneous behavior when evaluated at different scale, specially shales at the scale of interest of completion and drilling engineers. Shales shows different acoustic characteristics since encompasses the most common cases of anisotropy; stress, layering and, fractures. In this work we measure shear and compressional velocities at different frequency range to evaluate and characterize the anisotropy mechanisms in the Woodford shale. Incorporate frequency sweep of ultrasonic measurements of fractured lower Woodford shale could potentially discern and encompass anisotropy effects in hydraulic fracture modeling. We measure the seismic velocities parallel to the bedding, perpendicular to fracture, perpendicular to bedding and parallel to fractures. We estimate a dynamicand static elastic moduli (Shear, Bulk, Young modulus, and Poisson’s ratio) accounting the shear and compressional velocity differences. We input elastic moduli to generate a precise geomechanical model, and this model yields into a numerical simulation that allows us to quantify the difference in fracture performance and geometry. Also, the numerical model of a hydraulic fracture in terms of geometry, height and width, and fluid pressure distribution within the fracture/formation boundary. The results show us the impact of defining correctly the anisotropy mechanism to evaluate and budget efficient hydraulic fracture jobs. Woodford shale is of particular interest since this is one of the most drilled and completed plays in our current energetic landscape. Anisotropy characterization combining geology and reservoir engineering is paramount for well placement and well landing. Correct estimation of anisotropy at different frequencies aids in discerning anisotropy mechanisms that could potentially drive completion designs and better budgeting of financial resources.