深水弃井套管切割技术

深水水下井口尺寸大、强度高,由于水深增加导致切割过程中管柱受力复杂,加上切割工具的不成熟和作业经验缺乏,导致我国前期自营深水井在套管及水下井口切割弃井时遇到了很大的技术挑战,在作业时出现了不同程度的复杂情况。针对自营深水井及国外深水弃井施工案例,深入分析了深水弃井套管切割的风险点和技术难点,总结了作业失败的原因,从技术方案、弃井工具和施工参数等方面提出了针对性的改进方法,全面分析了深水弃井作业的风险点,并给出了相应预防控制措施,并在第2批深水井实施中得到了成功应用,提高了深水作业的安全性和时效性,证实了之前的改进思路的正确性,解决了深水弃井技术难题。

Casing cutting technology for abandoned deepwater wells

The deepwater subsea wellhead is of large size and high strength. The increasing water depth results in complexity of string stress during the cutting process. Plus immaturity of cutting tools and lack of experience, there is a great technical challenge to earlier self-support deepwater wells in China, when the abandoned wells’ of casing and subsea wellhead is cutting, which may result in complex conditions of varying degrees in the operation. Considering the construction cases of self-support deepwater wells and foreign deepwater abandoned wells, the risks and technical difficulties in casing cutting of deepwater abandoned wells are deeply analyzed, and the causes for failed operations are summarized. Methods to improve the technical solutions, abandoned well tools, and construction parameters are proposed. The risks in the operations of deepwater abandoned wells are fully analyzed and appropriate preventive and control measures are provided, which successfully applied in the second batch of deepwater wells to improve the safety and timeliness of deepwater operations. That confirms the correctness of the previous improvement ideas and solves the technical problems about deepwater abandoned wells.