深层页岩气连续油管钻磨桥塞技术

Coiled tubing drilling and milling bridge plug technology with for deep shale gas wells

随着川渝地区页岩气开发迈向深层,连续油管钻磨桥塞面临深层页岩气井口压力高、套变导致卡钻、频繁起下易导致油管失效等复杂工程,严重影响到连续油管在深层页岩气改造后钻磨的作业安全和时效。通过开展连续油管钻磨桥塞难点分析、适用于川南深层页岩气区块的变径连续油管结构优化、高温环境下循环用钻磨工作液体系优化、高压下钻磨桥塞工艺优化等方面的研究,形成了满足川南深层页岩气井的连续油管高压钻磨桥塞关键技术和配套工艺措施。经川南页岩气区块现场应用84井次,卡钻等复杂情况由前期5.3%下降至3.3%,钻磨桥塞由前期的3~5趟钻缩短至1~3趟钻,安全快速地实现了压裂后的井筒清理,缩短了钻磨桥塞的时间,提高了作业效率。该技术为川南深层页岩气安全高效开发提供了技术支撑。

As shale gas development in the Sichuan-Chongqing region advances into deeper layers,the use of coiled tubing for bridge plugs drilling and milling encounters significant engineering challenges.These challenges include high wellhead pressure in deep shale gas wells,drilling tool jamming due to casing deformation,and tubing failure because of frequent trips.These issues severely impact the safety and efficiency of coiled tubing operations post-stimulation in deep shale gas wells.By carrying out research on the aspects such as analysis of the difficulties in coiled tubing drilling and milling bridge plug,optimization on the structure of variable-diameter coiled tubing suitable for the deep shale gas blocks in southern Sichuan,optimization of circulating drilling and milling working fluid system in high temperature environment,and optimization on the process of drilling and milling bridge plug under high pressure,a set of key technologies and supporting measures for coiled tubing drilling and milling bridge plug was developed,meeting the needs of deep shale gas wells in southern Sichuan.Field applications in 84 wells in the southern Sichuan shale gas blocks reduced the incidence of complex issues such as drilling tool jamming from 5.3%to 3.3%,and the number of trips required for drilling and milling bridge plug decreased from 3~5 trips to 1~3 trips.This allowed for the safe and rapid cleaning of wellbores post-fracturing,shortened the time required for drilling and milling bridge plug,and improved operational efficiency.This technology provides a technical support for the safe and efficient development of deep shale gas in southern Sichuan.