页岩气水平井连续油管钻塞工艺

On Coiled Tubing Drill Out Technology in Shale Gas Horizontal Wells

针对页岩气水平井内进行连续油管钻除井内桥塞施工中存在碎屑返排难、钻塞效率低等问题,根据常规钻塞工艺的原理及页岩气水平井的特点,对连续油管钻塞管柱进了优化设计,对连续油管钻塞施工参数进行了优化,配套了碎屑大小控制技术、碎屑返排技术、钻塞管柱减阻技术和桥塞碎屑打捞技术。结果表明,采用凹面磨鞋作为钻磨工具,有效控制了碎屑大小;应用钻塞液闭式循环地面流程,能实现高压连续施工,降低了钻塞液的使用量;管柱中设计水力振荡器、在钻塞液中加入金属减阻剂,能延缓"自锁"现象的发生,增加可钻达深度;"强磁+文丘里"打捞技术对于清理井筒内碎屑具有较好的效果,基本解决了碎屑清理难的问题。

Aiming at such problems as hard chippings backflow and low drill out efficiency in coiled tubing drilling bridge plug operation in shale gas horizontal holes, optimization is made on the design of coiled tub- ing drill out string and the parameters of coiled tubing drill out operation on the basis of conventional drill out theory and shale gas horizontal well features, supported by chippings size control technology, chippings backflow technology, drill out string drag--reducing technology and chippings fishing technology. The ap- plied results show that the adoption of concave milling shoe as the drilling and grinding tool can effectively control the chippings size, that the application of drill out fluid closed circulating ground flow process can re- alize continuous operation under high pressure and reduce usage amount of drill out fluid, adding the Hydraulic oscillator to the string and metal drag reducer to drill out fluid can delay occurrence of the self--loc- king phenomenon and increase drillable depth and that strong magnetic ＋ Venturi salvage technique is suit- able for clearing up the chippings in the wellbore.