顺北油田超深井可回收式套管封隔器失效因素分析及改进对策

Failure factor analysis and improvement countermeasures of recyclable casing packer in ultra-deep wells in Shunbei Oilfield

顺北油田勘探开发过程中,以封隔器为核心的井下工具在使用中多次出现密封失效、解封失败等问题,大幅降低了完井作业成功率。对典型井封隔器失封原因进行分析,将失效因素分为工具质量和强度、坐封环境、交变载荷三大类,相应提出了从提高封隔器质量、降低泥浆沉淀、增强承变载能力三方面的改进措施,并对封隔器进行V3等级确认实验。经对顺北油田完井工具结构及作业流程进行调整,实现了不同规格工具的覆盖。改进后的工具在平均井深达7 500 m井的现场应用,成功率达100%。该方法为顺北油田超深井完井提供了技术支撑。

During the exploration and development of Shunbei Oilfield,the downhole tools with packer as the core have many problems such as sealing failure and unsealing failure,which greatly reduces the success rate of well completion.In this paper,the reasons for the sealing failure of packers in typical well are analyzed.The failure factors are divided into three categories;tool quality and strength,setting environment and alternating load.Accordingly,the improvement measures from three aspects of improving the quality of packers,reducing mud sedimentation and enhancing the load bearing capacity of packers are put forward,and the V3 grade confirmation experiments of packers are carried out.After adjusting the structure and operation flow of completion tools in Shunbei Oilfield,the coverage of tools with different specifications is achieved.The improved tool is applied in the field with an average well depth of 7500m with a 100%success rate.This method provides technical support for well completion of ultra-deep well in Shunbei Oilfield.