The Influence Between Natural Fracture and Hydraulic Fracture in Shale Reservoir

摘要

Based on linear elastic fracture mechanics, the forming mechanism of complex fracture system in shale reservoir are studied. The interference of the natural fracture and hydraulic fracture model and a new crack initiation angle calculation model is established, and the influence factors of critical differential stress level and new crack initiation angle are analyzed. The impact of natural fracture dip and natural fracture density on complex fracture network are researched. Calculation results show that the lower approximation Angle and high pressure in the fracture is the necessary conditions of forming fracture network; Under the condition of lower stress difference and high internal pressure, the new crack can be faster to the maximum horizontal in-situ stress direction, connect more natural fracture; in order to get a complex fracture network in shale reservoir in the need to constantly improve the pressure to activate and connect higher approaching Angle and distance of natural fracture. The research results have important reference value in understanding the formation mechanism of complex fracture network in shale reservoir, can also be used for shale fracturing design and fracturing interval optimization.