隐患井井筒完整封堵方法研究与应用

Research and Application of Complete Blocking Method for Wellbore of Hidden Wells

随着油气田开发的深入,部分油气水井进入开发中后期,已无良好经济价值。对于需要永久性报废处理的废弃井,既要阻止地层流体在井内运移,也要防止油气沿井筒垂直运移到淡水层或地面。应保证井筒及套管环空同时有效封隔,形成井筒机械完整性以达到封堵目的。通常选择适当井段进行注水泥塞或坐封机械桥塞来阻止流体运移,而井筒外封堵采用锻铣再封堵工艺,但锻铣套管受诸多因素影响,速率低且风险高。本文探索另一种新工艺:射孔二次补注封堵,即对目的井段进行补射孔,建立局部连通,使用超细水泥浆二次固井形成完整水泥隔板,重新建立封堵井屏障。实际应用安全、高效、经济,获得满意效果,为隐患井治理提供新技术思路和经验。

With the deepening of oil and gas field development,some oil,gas,and water wells are in the middle and late stages of develop-ment and no longer have good economic value.For the abandoned wells that need to be permanently scrapped and disposed of,it is necessary to stop the transportation of formation fluids in the well as well as to prevent the vertical transportation of oil and gas along the wellbore to the fresh-water layer or the surface.It should be ensured that the wellbore and casing annulus are effectively sealed at the same time to form the mechanical integrity of the wellbore for the purpose of plugging.Usually,a proper well section is selected for cement plugging or mechanical bridge plugging to prevent fluid transportation,while the outer wellbore plugging adopts the process of forging and milling and then plugging,but the forging and mill-ing casing is affected by many factors,the rate is low and the risk is high.In this paper,we explore another new process:shot hole secondary plug-ging,i.e.,the purpose of the well section is to make a supplementary shot hole to establish a local connection,and then use ultra-fine cement slurry to cement the well twice to form a complete cement spacer,and then re-establish the plugging well barrier.The practical application is safe,efficient and economical,obtaining satisfactory results and providing new technical ideas and experience for the management of hidden wells.