中江19H井卡钻原因分析及预防技术措施

Analysis on the Reasons of Drill Rod Sticking in Well 19H of Zhongjiang District and the Preventive Measures

摘要:

中江19H井是川西中江地区的一口长水平段水平井，设计井深3830 m，水平段长990 m。目的层为下沙溪庙组，是开发中江地区该层位的首口水平井，邻井参考资料少。中江地区地层裂缝发育，普遍存在井壁失稳现象，极易产生掉块，同时，该井设计二开裸眼段长，更恶化了井壁失稳，施工中产生大量掉块，掉块在井眼局部堆积形成砂桥造成该井水平段卡钻。仔细分析了该井卡钻原因，提出了优化钻井液性能、优选钻井工具、优化水平段钻具组合、加强井眼净化等相应预防技术措施，顺利完成了该井的后期侧钻施工。为川西中江地区下沙溪庙目的层的开发提供了宝贵施工经验。

Abstract:

Well 19H of Zhongjiang is a long horizontal well with designed depth of 3830m and 990m in the horizontal section. The fracture develops in this district with wide spreading well wall instability and block falling. The design of the second open hole section makes the wall instability even worse, the sand bridge may be formed by local accumulation of falling blocks in the well bore to cause drill rod sticking. The reasons of drill rod sticking are analyzed in this paper, the corresponding preventive measures are put forward in optimization of drilling fluid performance, drilling tools and drilling tool assembly for horizontal section as well as reinforcing well bore clarification. The later sidetracking construction is successfully completed, which provides some valuable experiences for drilling work in this district.