Integrating the Fully Coupled 3D Geomechanical Modeling for Hydraulic Fracturing Optimization of Unconventional Resources

Abstract

Abstract The unconventional oil and gas resources continuously discovered in China are mainly concentrated in the Junggar Basin, Ordos Basin, Sichuan Basin and Songliao Basin. However, the porosity and permeability of its shale reservoirs are extremely low, which brings relatively great difficulties and challenges to the economic development of shale oil reservoir. Long horizontal well section drilling and multi-stage hydraulic fracturing are the key technologies of unconventional resources development. The operations can increase the stimulated volume and ultimately achieve the goal of improving production. In addition, shale reservoirs natural fractures and horizontal bedding are developed, leading to shear slip and tensile failure during the fracturing propagation process. Moreover, the hydraulic fracture is no longer a single symmetrical two-wing fracture, and it is very likely to form a relatively very complex fracture network. This will bring many inconveniences to shale hydraulic fracturing design, fracture monitoring and interpretation, and post-fracturing productivity prediction. Geomechanics is the important influencing parameter that affects the design of hydraulic fracturing. This research is mainly based on the research results of 3D geomechanics to continuously optimize hydraulic fracturing design for horizontal wells. In addition, the implementation of hydraulic fracturing can significantly reduce the seepage resistance of fluids in the formation near the bottom of the well. This will be a very effective mean to increase well production for unconventional resources. Hydraulic fracturing optimization technique fully-coupling 3D geomechanical modeling was applied in the unconventional reservoir in the northeast of Junggar Basin. The shale oil reservoir of Permian Lucaogou formation is one of the main unconventional resources in China. This case study discusses the multi-stages fracturing optimization of horizontal well-A based on the fully coupled 3D Geomechanical modeling. The research result clearly characterizes the stress model variation and reduces the uncertainties in horizontal well-A1 for hydraulic fracturing operation. The uncertainty of the fracture modeling geometry was greatly reduced, and fracture geometry was verified by micro-seismic patterns. The geomechanical modeling helps to optimize the pressure pumping rate, the volume of proppant and fracturing fluids, eventually maximizes the increase of fracture flow conductivity and post-stimulation production.