Discovery and implications of the large deep coalbed methane in Shenfu gas field

Background After nearly 20 years of unconventional natural gas exploration in the Shenfu area on the eastern margin of the Ordos Basin, a deep coalbed methane reserve of 100 billion cubic meters was discovered in 2023. In the early stage of deep coalbed methane exploration, it faced challenges such as insufficient geological understanding, immature fracturing technology, and lack of experience in drainage technology. Methods and Results Through management and technological innovation, driven by both wheels, good results have been achieved. In terms of management, innovative measures were taken to implement "complementary" and "vertical" exploration of deep coal seams and tight sandstone gas, breaking down professional barriers, organizational barriers, and business barriers, adhering to the principle of "one well, one policy", and efficiently promoting the integration of "drilling-fracturing-drainage". Technically, the innovative deep coalbed methane accumulation model of "microfacies-controlled coal, source heat-controlled hydrocarbon, temperature and pressure-controlled existence state" was proposed, and selection criteria and enrichment areas were established, forming a geological engineering sweet spot evaluation technology. The application of composite three-dimensional fracture network transformation technology was explored to maximize the transformation volume of coal reservoirs and optimize the seepage capacity. Significance The drainage ideas of "rapid backflow-multi-level pressure control-steady stepped production increase" were proposed according to local conditions, forming Undersaturated well and saturated well two major types of drainage systems, clarifying the target principles of different drainage stages, and establishing three types of bottomhole flow pressure decline models, and supporting exploration wells to achieve and stabilize production.