Research on Environment-Friendly Fracturing Technologies and Practices for Shale Gas Plays in China

Abstract At present, shale gas development mainly relies on hydraulic fracturing. However, hydraulic fracturing is associated with significant drawbacks, including high water consumption, severe reservoir damage, and risks of water environmental pollution. In recent years, waterless or low-water fracturing technologies have attracted increasing attention because they can effectively mitigate the shale water-lock effect and reduce reservoir damage. To reduce water consumption and environmental risks during unconventional reservoir stimulation, a systematic investigation of waterless fracturing technologies for shale gas was conducted. Through literature survey, comparative analysis, and case studies, the implementation characteristics, advantages, and limitations of hydraulic fracturing, waterless fracturing technologies such as supercritical CO2 fracturing, and foam fracturing were comprehensively summarized and analyzed, and future development trends of fracturing technologies were discussed and prospected. The results indicate that current environment-friendly fracturing technologies mainly include novel chemicals, advanced flowback control equipment, liquid CO2 fracturing, supercritical CO2 fracturing, liquid N2 fracturing, liquefied petroleum gas (LPG) fracturing, and foam fracturing. These technologies exhibit good compatibility with reservoir fluids, strong fracture-creating capability, and favorable production enhancement performance. Foam fracturing fluids possess excellent proppant-carrying and proppant-transport capabilities, enabling proppants to be more effectively distributed throughout the entire fracture network. Under the strategic background of carbon peaking and carbon neutrality in China, CO2 fracturing technologies can achieve both resource utilization and geological sequestration of CO2. Therefore, their CO2 emission reduction potential should be comprehensively considered when selecting appropriate fracturing technologies.