The Effect of Operational Parameters on Hydraulic Fracture Propagation in Naturally Fractured Reservoirs - Getting Control of the Fracture Optimization Process

摘要

With the huge growth in the stimulation of naturally fractured formations, it is clear that the industry needs new hydraulic fracturing simulation tools beyond the limits imposed by pseudo3D fracturing models. Discrete element models (DEM), in which both matrix block behavior and fracture behavior are explicitly modeled, offer one, option for the specific modeling of hydraulic fracture (HF) creation and growth in naturally fractured reservoirs (NFR) without, for example, the assumption of biplanar fracture growth. In this paper, we show the results of successful, realistic simulations of fluid injection into a given NFR using the 3DEC DEM model. The simulations included: a) coupled fluid flow-deformation analysis; b) failure type and extent evaluations; and c) parametric analyses of the influence of injection rate and fluid viscosity on the ratio of tensile (mode. 1) failure to shear failure. The understanding of the factors affecting the tensile/shear failure ratio, in particular, provide a first-step towards optimizing HF operations and promoting the creation of "complexity' in the HF/NFR system.