Fracturing Design Aimed at Enhancing Fracture Complexity

Abstract

Abstract The potential for shale formations as a source of gas production has been recognized. However, shale permeability in a nano-Darcy scale represents a significant technological challenge to recover trapped hydrocarbon effectively. The fracturing of wells has been widely used to enhance the economic aspects of the reservoir. Connecting the created hydraulic fractures to the natural fractures or induced-stress fractures would further improve the productivity of the wells. Fracturing heterogeneous (naturally fractured) formation involves unique aspects in the fracturing processes, rock mechanics, and fluid-flow aspects. In some cases, the natural fractures might not be sufficiently conductive or could be held closed during fracturing operations as a result of the existing in-situ stresses. In this paper, hydraulic fracturing-design techniques to neutralize the stress anisotropy in the formation to allow the opening of the natural fractures during the hydraulic-fracture propagation are presented. Overcoming anisotropy effects would allow the operator to inject moderate amounts of proppant into the natural fractures and maximize the contact area within the reservoir. Geomechanics development behind these techniques is presented in this paper. The presented technology would allow operators to optimize placement of fractures across the horizontal well based on the geomechanics properties of the formation. The fluid-flow aspects of these enhanced completion processes are also discussed.