Interaction of Multiple Non-Planar Hydraulic Fractures in Horizontal Wells

The use of multi-fracced horizontal well technology is one of the key reasons for the recent success in the exploitation of unconventional resources such as shale gas and shale oil. This technology of placing multiple fractures in horizontal wells has provided economic production rates resulting in the prevalent development of unconventional oil and gas reservoirs. The fracture stimulation process typically involves placing multiple fractures stage by stage along the horizontal well using diverse well completion technologies. The effective design of such massive fracture stimulation requires an understanding of how multiple hydraulic fractures would grow and interact with each other in heterogeneous formations. This is especially challenging as the interaction of these fractures are subject to the dynamic process of subsurface geomechanical stress changes induced by the fracture treatment itself. This paper presents a new three dimensional (3D) hydraulic fracture computational simulator which describes non-planar hydraulic fracture growth in heterogeneous formations. It addresses the geomechanical interaction of multiple fractures, and can be extended to considering interaction with natural fractures as well. In this model, the interaction of multiple non-planar fractures is meticulously captured by means of boundary integral formulation with dislocation segments solution techniques. The flow of proppant laden frac fluid within a fracture is represented by a power-law fluid model according to the Reynolds lubrication theory. The derived non-linear fracture growth and fluid flow equations are solved in a coupled manner via a proprietary, robust and efficient algorithm where mass conservation (i.e., frac fluid and proppant) is strictly observed. Examples are presented to demonstrate that the present numerical approach can be used to provide a much needed insight into the growth of multiple fractures under the influence of subsurface geomechanical stress ‘shadows’ and thus, serve as a valuable tool for optimization of multiple hydraulic fractures design.