The influencing parameters and improve methods of acid-etched fracture conductivity: A review

Deep and ultra-deep reservoirs have been discovered with the development of exploration technology. Under high and ultra -high closure stress, the conductivity of fractures is rapidly reduced, which affects the economic exploitation of hydrocarbon and other underground resources (such as geothermal resources). Therefore, it is urgent to improve the fracture conductivity under high and ultra -high closure stress. Based on the characterization of acid fractures and the influencing factors of acid fracture conductivity, this study divides the influence of different factors on fracture conductivity into two parts: the influence on the initial conductivity and the conductivity retention rate. The idea of improving the fracture conductivity is proposed: The formation of channel etching pattern under high and ultra -high closure stress can not only obtain high initial conductivity, but also reduce the sensitivity of conductivity to closure stress through sheet support. Enhancing the strength of supporting point by adding proppant or consolidation reagents is beneficial to maintaining the fracture conductivity under high closure stress. Some mature or immature methods for improving the fracture conductivity of carbonate are introduced, aiming to provide new ideas for improving the fracture conductivity under high and ultra -high closure stress conditions.