Discussion on Several Key Issues of the New-Generation Network Fracturing Technologies for Unconventional Reservoirs

Network fracturing technologies are the key to the efficient development of unconventional reservoirs. The degree of tight spacing, the intensity of proppant injection, the number of temporary plugging stages, and operation parameters are constantly optimized to maximize the effective stimulated reservoir volume (ESRV) and single-well estimated ultimate recovery (EUR), ultimately adding to the increasingly high comprehensive costs of fracturing operations. For this reason, new-generation network fracturing technologies (namely, three-dimensional fracture network fracturing technologies) were investigated and tested. Regarding the development of the fracturing process, a mode of “moderate tight spacing, high-intensity proppant injection to multi-scale fractures, multi-stage dual temporary plugging, and whole-process layer-penetrating” was gradually ushered into practice. Several key issues were discussed to further the development, promotion, and application of three-dimensional fracture network fracturing technologies. These issues involved the characterization of three-dimensional fracture networks, the determination of the fracturing mode and parameter boundaries, the synergistic enhanced oil recovery (EOR) mechanism of “fracturing-imbibition-energy enhancement-oil displacement”, integrated multi-functional fracturing fluids, the analysis of the economic efficiency of replacing ceramsite with quartz sand, and the establishment of a closed-loop system upgraded by cyclic iteration of “design-implementation-post-frac evaluation”. In this way, the concepts, key technologies, and the EOR mechanism of the three-dimensional fracturing technologies were clarified. Important reference and guidance can be provided by this paper for the rapid development of new-generation fracturing technologies for unconventional oil reservoirs and better fulfillment of the requirements for efficient exploration and development of unconventional reservoirs.