织金煤层气浅层大位移水平井钻完井技术

Drilling and completion technologies for extended-reach shallow CBM wells in Zhijin

针对织金区块存在表层漏失、摩阻大、下套管困难等难题,从堵漏方式优选、井眼轨道优化设计、井身结构优化、钻井液体系优选、完井管串优化等方面进行了织金煤层气浅层大位移水平井钻完井技术研究,并在ZP-4井进行了成功应用。采用"导管跟钻"技术成功解决了表层漏失难题;采用优化的双增轨道设计,在满足近钻头地质导向对着陆点垂深精确调整的要求下,避免了单增轨道调整后容易出现"S"型轨迹的现象,降低了摩阻,保证了中靶精度;采用优化的完井管柱设计,成功实现了浅层大位移水平井生产套管的顺利下入。实践表明,织金煤层气浅层大位移水平井钻完井技术解决了该区块钻井存在的表层漏失、摩阻大、下套管困难等难题,为织金区块后续低成本、高效开发提供了技术支持。

To address the issues of lost circulation, big friction and difficult casing running while drilling surface holes in the Zhijin Block, drilling and completion technologies for extended-reach shallow coalbed methane(CBM) wells in the Zhijin Block were analyzed and successfully applied in Well ZP-4. These technologies include the selection of plugging approaches, optimized design of borehole trajectories, optimization of wellbore structures, selection of drilling fluid systems and optimization of completion strings. A technique of drilling with conductor pipes successfully solved the lost circulation problem. An optimized design of two-buildup trajectories allowed for accurately adjusting the vertical depth of landing points through near-bit geosteering. With this two-buildup trajectory design, no S-shaped trajectories were generated as single-buildup trajectory design did;friction was reduced and targets could be hit easily. An optimized design of completion strings enabled production casings to be successfully run in extended-reach shallow horizontal wells. Practices indicate that these drilling and completion technologies for extended-reach shallow CBM wells in the Zhijin Block solved the issues of lost circulation, big friction and difficult casing running while drilling surface holes and provided technical supports for further developing the Zhijin block with low cost and high efficiency.