Stress evolution and fracture propagation of infill well after production and injection of parent well in a tight oil reservoir

Abstract

Abstract Stimulation of unconventional tight oil formations via horizontal wells has seen increasing cases of fracturing infill wells in recent years. The effectiveness of such a strategy is mainly dependent on the proper characterization of the stress evolution and an accurate forecast of the subsequent fracture propagation in the region neighboring the infill wells after considering the production performance and the injection schemes of the parent wells. In this respect, a comprehensive approach was proposed to simulate the stress evolution caused by the production and injection of the parent wells. The approach can also predict the upcoming fracture propagation behavior of the infill well. It was found that depletion in the parent wells can result in dramatic changes of the stress field, highlighted by apparent decreases in the magnitude of the minimum horizontal stress and changes in its orientation. Controlled injection in the parent wells can reproduce the original stress field, which favors the transverse extension of the fracture network in the infill well. In contrast, soaking well alone has little effect on improving the stress field. Therefore, this study suggests optimal injection schemes for parent wells and provides insights for fracture cluster designs in an infill well, eventually leading to maximized productivity of the infill well.

Keywords

• Tight oil formation
• Conglomerate reservoir
• Stress evolution
• Injection
• Infill well
• Parent well