Development of a Fully Three-Dimensional Simulator for Analysis and Design of Hydraulic Fracturing

This paper describes the formulation and numerical implementation of the framework for a full three-dimensional hydraulic fracturing simulator (3DHFRAC). Solid rock deformation is described by efficient singular integral equation techniques and fluid flow in the fracture is captured by effective viarational/finite-element methods. The choice of (local vs. global) interpolation techniques allows the same mesh to be used for both processes, and major mesh regeneration costs are greatly reduced. The computationally prohibitive problem of fluid flow near and propagation of the fracture perimeter is rendered tractable by means of a leading-edge concept, which draws on existing experience with simpler models. Testing of the model components is demonstrated by solving some crack-opening and fluid flow problems with existing solutions; then the overall model is verified with reference to simpler models, for circular, CGD and P3DH-type fracture geometries. Further, the containment role of barriers to fracture growth-specifically confining stress variations between reservoir and adjacent strata--is demonstrated; the more general potential of the model to describe the role of the many other mechanisms is emphasized, thus allowing calibration of simpler models or even direct use for treatment design.