APPLICATION OF GEOMECHANICAL MODELING TO HYDRAULIC FRACTURING DESIGN

Abstract

Hydraulic fracturing (HF) remains the primary stimulation technique, and for low-permeability reservoirs it is a prerequisite for economically viable development. At the same time, the production gain delivered by the treatment sharply increases the risk of fracture breakthrough into water- and gas-saturated intervals, which in turn degrades recovery efficiency. Minimizing such risks calls for robust, physically sound HF designs that prevent out-of-zone height growth while sustaining high well productivity.Since fracture geometry is controlled largely by elastic properties (Young’s modulus, Poisson’s ratio) and stress gradients, the key task reduces to ensuring the reliability of these parameters. This raises the question of using not generic reference values, but rather data derived from site- and formation-specific logging and testing. Core tests from target intervals are calibrated against acoustic logging data (compressional and shear wave times) with subsequent conversion from dynamic to static elastic parameters.The proposed approach was validated on a field in Western Siberia. Within the pilot area, a set of typical challenges was identified, research objectives were formulated, and a geomechanical model was constructed. For the initial geomechanical model, data from neighbouring fields were utilized. Within the distinguished mechanical facies of the section, the well-log curves involved in the calculations underwent filtering, correction, and reconstruction. In addition, core-based correlation relationships were employed for the computations. On this basis, continuous profiles of elastic-strength properties, overburden and pore pressures, and in-situ stress components were calculated.The derived relationships were incorporated into the geomechanical property library of a frac simulator. As a result, elastic and strength characteristics can now be estimated using only the lithological subdivision obtained from standard log interpretation data (RIGIS) and the pore pressure gradient at the time of treatment planning. Directions for future work have been outlined, and a comparative analysis of conventional HF design practices versus the geomechanics-based approach has been performed.