Abstract:
Horizontal well staged fracturing technology is a crucial approach for the efficient extraction of coalbed methane (CBM). Addressing the key challenges that significantly constrain the high and stable production of CBM wells in the Pingdingshan mining area—including the prevalent development of tectonic coal, difficulties in drilling horizontal wells, ineffective fracturing stimulation, and vulnerability of production channels—this study developed a comprehensive technical solution tailored to the unique geological characteristics of the local coal reservoirs. Through optimized drilling process parameters and advanced trajectory control technology, the drilling efficiency and horizontal section length were substantially improved. Fully considering the gas and water production characteristics at different drainage stages of coalbed methane wells in structurally complex coalfields, a precision-controlled drainage protocol was formulated and implemented in the field. Key findings demonstrate that the innovative “dual-gamma accurate identification + borehole wall stabilization + single-pass rapid drilling” system increased horizontal well length by over 150%, reduced drilling cycles. The novel “differentiated fracturing for tectonic coal” approach, incorporating primary/fragmented coal perforation, high-rate injection, optimized sand ratios, and low-density ceramic proppants, effectively stimulated structural coal reservoirs and expanded fracture networks. The proposed four-stage production management system(“pressure relief-desorption →casing pressure buildup →controlled pressure buildup → stable production”) ensured continuous drainage while minimizing workover requirements. Field applications yielded exceptional results: a maximum daily gas production exceeding 6 500 m
3, averaging 5 500 m
3/d, and currently cumulative output of 10
6 m
3—demonstrating remarkable sustainability. These technological breakthroughs provide valuable insights for optimizing CBM development in the Pingdingshan area and similar structural coal reservoirs, offering significant potential for enhancing energy recovery efficiency.