沁水盆地高煤阶煤层气高效开发关键技术与实践

Key technologies and practices for efficient development of high-rank CBM in the Qinshui Basin

中国高煤阶煤层气资源量丰富,占煤层气总地质资源量的三分之一,其高效开发利用对保障国家能源战略安全,降低煤矿生产安全隐患,减少二氧化碳排放具有重要意义。为了解决制约我国高煤阶煤层气产业发展的“四低”(探明储量有效动用率低、产能到位率低、单井产量低、开发利润低)问题,在深入分析制约高煤阶煤层气开发核心问题的基础上,通过理论研究与技术研发并重、室内攻关与现场试验并行,规模建设与效益开发并举等多种举措,提出了控产选区评价等新方法。研究结果表明:①煤层气地质和煤矿地质差异、储量可开采性差异、工程技术适应性、排采科学性是制约煤层气开发效果的主要因素;②提出了“四要素”控产认识,疏导式工程改造方法,疏导式排采控制认识,指导建立了高煤阶煤层气高效开发技术系列;③经实践,优质储量控制程度由32%提高到80%,开发井成功率由60%提高至95%,直井平均单井日产气量提高约1100 m^(3),水平井钻井费用降低50%,单方气操作成本降低24%。结论认为,建立的高煤阶煤层气高效开发技术系列,有力推进了沁水盆地煤层气高效开发,“十四五”中期,中国石油华北油田煤层气年产气量有望达到20×10^(8)m^(3),助推了我国煤层气的战略性发展。

There are abundant high-rank coalbed methane(CBM)resources in China,accounting for one third of total CBM resources.Its efficient development and utilization is of great significance to guarantee the national energy strategic security,diminish the hidden danger of coal mine production and reduce carbon dioxide emission.In order to solve the"Four Lows"problem(i.e.,low effective utilization ratio of proved reserves,low productivity targeting ratio,low single-well production rate,and low development profit)restricting the development of high-rank CBM industry in China,this paper deeply analyzes the core problems restricting the development of highrank CBM.Based on this,several new methods of production control,area selection and evaluation are put forward by taking multiple measures,such as paying the same attention to theoretical and technological research&development,carrying out laboratory research and field tests in parallel and conducting large-scale construction and benefit development simultaneously.And the following research results are obtained.First,the geological difference between CBM and coal mine,the difference in reserves recoverability,the adaptability of engineering technology and the scientificity of production are the main factors restricting the CBM development effect.Second,"Four-element"production control theory,methane-leading engineering transformation method and methane-leading production control theory are proposed,which provides guidance for the development of a series of technologies for the efficient development of high-rank CBM.Third,in practice,the control degree of quality reserves is increased from 32%to 80%,the success ratio of development wells is increased from 60%to 95%,the average single-well daily gas production of vertical wells is increased by about 1100 m^(3),the drilling cost of horizontal wells is reduced by 50%,and the operation cost per cubic meter of gas is reduced by 24%.In conclusion,the established technology series for the efficient development of high-rank CBM actively promote the efficient CBM development in the Qinshui Basin.The annual CBM production of PetroChina Huabei Oilfield Company is expected to reach 20×10^(8) m^(3) in the middle of the"14^(th) Five-Year Plan",which promotes the strategic development of CBM industry in China.