Unified Approach to Hydraulic Fracturing and Reservoir Simulation

In this paper, we present a new parameterization of the hydraulic fracturing modeling which allows the use of a coupled flow/geomechanics reservoir simulator to predict fracture propagation. To do this we used our in-house reservoir simulator (OpenSim) which implements a fully coupled flow/geomechanics formulation, where the fluid-flow is modeled following conventional black-oil model. To simulate the hydraulic fracturing process, we define a critical strain to allow the fracture to propagate which can be conceptually related to the stress intensity factor. The permeability of fractured blocks is related to its strain assuming that the deformation is associated with the presence of a local fracture. Once a given block reaches the critical conditions, both its mechanical properties and permeability/strain behavior are modified to mimic that of a fractured block. Leak-off is naturally included in our model as the fluid transfer between fractures and matrix is ruled by the usual flow parameters (permeability, pressure, and saturation). Proppant transport is not considered explicitly, however, the water saturation distribution can be used to build a proxy for the proppant distribution. We present results for realistic models and run sensitivities to the different model parameters.