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平顶山构造煤区煤层气水平井高效开发技术与应用

Efficient development technology and application of coalbed methane horizontal wells in structural coal area of pingdingshan

  • 摘要: 水平井分段压裂技术已经成为煤层气高效开发的重要手段。平顶山矿区构造煤广泛发育、水平井钻井成孔难、压裂改造效果差、煤层气产气通道易破坏等严重制约煤层气水平井高产稳产。基于该矿区煤储层地质特征,通过改进钻井工艺参数和轨迹精准控制技术提高了钻井成孔效率与水平段长度;采用煤体结构精准识别和数值模拟方法优化了压裂施工参数和支撑剂粒径配比;充分考虑构造煤区煤层气井不同排采阶段的气水产出特征,制定了精细化的排采工作制度并进行了现场应用。结果表明:研发的“双伽马精准识别+泥浆护壁+一趟钻快速钻进”的构造煤水平段快速成孔技术体系,使构造煤中水平段长度提高1.5倍以上,有效缩短了钻井周期;构建的“原生/碎裂煤中射孔+大排量+中/低砂比+低密度陶粒”的构造煤差异化压裂技术体系,实现了构造煤储层有效造缝,扩大了有效缝网面积;提出的“降压解吸段−套压上涨段−控压提产段−稳产段”等阶段排采工作制度保障了构造煤储层排采的连续性,减少了修井频次。四2煤层水平井的最高日产气量为6 500 m3,目前累计产气量达到106 m3,平均5 500 m3/d;并能持续稳产,显示出良好的应用前景。该研究成果为平顶山构造煤区及类似地质条件下煤层气水平井高效开发提供了重要借鉴和技术支撑。

     

    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 m3, averaging 5 500 m3/d, and currently cumulative output of 106 m3—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.

     

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