Research on Productivity Recovery Mechanism of Fractured Parent Well of Interwell Stereodimensional Infill Well in Fuling Shale Gas Reservoir, Sichuan Basin

Abstract

ABSTRACT During the fracturing process of infill wells in the Fuling shale gas reservoir, it was found through real-time monitoring of fracturing that the monitored pressure of the parent well increased to different degrees when each fractured stage of the adjacent infill wells was fractured, and a significant increase in production following the re-opening of the well. To study the production and pressure recovery mechanisms of parent well associated with the infill well fracturing, a coupled flow and geomechanics model was established based on the comprehensive work flow of four-dimensional in-situ stress during the devolopement of multi-layer three-dimensional infill horizontal well in shale gas reservoir. In the integrated modeling, a natural fractures network was embedded in the geological model firstly. Second, a fracturing model is developed to simulate hydraulic fracture propagation of parent wells. Thirdly, a coupling flow and geomechanics model was established to simulate the spatiotemporal stress evolution in a multilayer shale gas reservoir with complex fracture geometry. Finally, the complex hydraulic fractures propagation of the infill well was stimulated. It can be concluded from the simulation results that: (1) Reservoir stress changes are influenced by fracture modification, but the range of stress evolution is greater than the range of fracture modification; (2) The natural fracture zone connects the fractured wells to the producing wells, and the fluid can be run long distances through the natural fracture zone to the fracture modification edge of the old wells to achieve the fracturing of more wells and to increase the production of the old wells (3) The fractures(tennsile fractures, shear fractures) communicating between the fractured edges of the tightened wells and the old wells are able to transfer fracturing fluids and add production to the old wells. This discovery is beneficial to the production of fractured encrypted wells and the continued high production of old wells.