Multistage hydraulic fracturing technique now applied with horizontal wells and over large areas has enabled commercial production of oil and gas from low-permeability rock formations, changing the energy landscape in North America. In these reservoirs, tons of fracturing fluid and proppants are pumped into the reservoir matrix to create hydraulic fractures and it is important to understand the propagation mechanism of hydraulic fractures and further optimize their properties. In addition, natural fractures are often present in the shale and tight formations, which might be activated during the fracturing process and contribute to the after-stimulation well production rates.

In this paper, reservoir simulation is coupled with rock mechanics to predict the well after-stimulation production performance. Firstly, a dual-permeability geological model is built based on field data collected from a well pad in Montney formation, Canada. Fracturing fluid flow in the formation coupled rock mechanics is employed to simulate dynamic hydraulic fracturing process. More specifically, as the continuous injection of fracturing flurry, the effective stress will decrease accordingly. When the effective stress reaches the rock failure criteria, hydraulic fractures will be generated, allowing the fracturing liquid to flow along the fractures. Based on the fracturing operational schedule, dynamic hydraulic fracturing simulation is conducted and results show that hydraulic fractures tend to propagate upward first until it connects the entire formation in the vertical direction. Early production history of the stimulated well is then matched to valid the simulated fracture geometries. Finally, the effects of natural fractures and well bottom-hole pressure on well production are studied. Results show that if natural fracture can be propped or partially propped by the proppants, the production will be increased significantly for shale liquid rich gas plays. This paper provides a significant insights on the fracture propagation and can be a reference for fracturing treatments in unconventional shale reservoirs.

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