S22井利用地层压力辅助解封封隔器技术

The Technology for Releasing Packers by means of Formation Pressure in Well S22

  • 摘要: AHR封隔器坐封在油气井的大斜度段或水平段时,采取常规的过提方法解封封隔器困难,处理不当可能造成大修事故.在分析AHR封隔器结构和工作原理基础上,进行水平井管柱轴向受力分析,模拟计算施加在井口的过提力能够传递到封隔器上的轴向拉力;在油管的额定抗拉负荷内,如果轴向拉力达不到封隔器的预定解封力,用连续油管正循环注入氮气,掏空油管内的部分液体,释放地层压力对封隔器的上顶力,同时上提油管柱,可以剪断销钉实现封隔器解封.国外Y油田S22井的井口上提力达到油管的额定抗拉强度921 kN时,下传到封隔器的轴向拉力仅为236 kN;掏空1 650 m的油套管液柱,释放地层压力的上顶力为205 kN,作用在封隔器销钉的合力可达到预定剪断值441 kN,成功实现了封隔器解封.现场应用表明,掏空油管内部分液体释放地层压力的上顶力,可以补偿上提管柱解封封隔器时管柱抗拉强度的不足,为大斜度井、水平井中解封封隔器提供了新的方法.

     

    Abstract: AHR packer retrieval by normal overpull can be difficult when they have been set in highly deviated or horizontal sections,or when improper operations have caused workover problem.The axial force of tubing in horizontal well was analyzed based on structure and mechanism analysis of the AHR packer,and the over pull force that transmitted to the packer was simulated.Within the rated tensile strength of tubing if the overpull was not sufficient to overcome the preset releasing force of the packer,coil tubing could be utilized to evacuate the tubing by pumping nitrogen through positive circulation,and release formation pressure to push the packer upwards,at the same time, tubing could be pulled for shearing off the pins and releasing the packer.Taking Well S22 in Y field as an example,when the pulling force reached a tensile strength of 921 kN,the force transmitted to the packer was only 236 kN,then 1 650 m was tubing was evacuated and 205 kN upwards force was released,the total force applied to the pins of the packer was 441 kN,the packer was successfully released.The study demonstrated that the evacuation of partial fluid to release the formation pressure can compensate for the insufficient releasing force on the packer,and the approach can provide reference of theory and practice for releasing packers in highly deviated or horizontal wells.

     

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