中国煤层气钻井技术现状及发展趋势

对我国煤层气钻井完井技术现状进行了归纳和总结,结果认为:煤储层地质基础薄弱、井壁易失稳、煤层损害严重以及完井效果差等难题严重制约了我国煤层气高效勘探开发;已开展的多分支水平井技术、U型井技术及其配套的连通和裸眼造洞穴等技术取得了长足进展,一定程度上缓解了以上技术难题的制约。生产实践表明,由清水钻井引起的钻井安全与煤层保护的矛盾仍然突出,国内煤层气产量依然偏低。进而建议,加强对煤层专用钻井液、煤层损害解除方法的研究,尽快制定煤层气钻井相关室内实验评价方法和矿场评价方法的行业及国家标准,探索矿权制度改革,开展煤层气与常规气、致密气合采关键技术研究,积极开展煤层气多层钻完井、复杂结构井增产措施配套技术研究。

State-of-the-art and developing trend of CBM drilling technologies in China

Many bottlenecking technical difficulties including weak geological foundation, poor wellbore stability, serious damage to coal seams during drilling, etc. are seriously hampering the coalbed methane (CBM) exploration and development in China. However, some progress made in multi lateral horizontal well technology, U shape well technology and their supporting techniques in connection and bare hole cave well completion, has alleviated the above problems to a certain degree. The production practices show that the conflict between drilling safety and coal protection resulted from water drilling is still prominent and CBM production is still low. In order to effectively improve the exploration and development benefit of CBM, we presented some suggestions as follows.(1) Specific drilling fluids for coal seams and some relief methods for damage to coal seams should be researched and developed. (2) The unified industrial codes and national standards should be soon formulated for CBM drilling related experimental and field evaluation methods. (3) The mining right system reform should be explored and deepened. (4) Further studies should be conducted of technologies in the combined production of CBM, conventional gas, and tight gas, and some CBM enhanced technologies like multilayer drilling and completion, complex structure well stimulation techniques, and so on.