海上高风险井弃置降本增效关键技术及应用

海上高风险井弃置存在井下情况复杂、管柱腐蚀严重、环空带压等问题。以某气田为例,分析了各层套管带压原因,建立了安全高效的压井起管柱作业流程。通过切割效率及切割效果对比分析,优选了腐蚀管柱高效切割技术、多层套管整体切割技术,形成了底部生产管柱高效封堵技术。研究了基于经济性的弃井机具优选原则,形成了海上高风险井安全高效弃置关键技术。实践证明,该技术体系效果好、成本低,在目标气田的弃置中取得良好效果,平均单井节约作业工期5～10 d。为国内海上高风险油气井高效低成本弃置作业提供借鉴。

Key Technologies and Application for Abandoning Offshore High Risk Wells Cost Reduction and Efficiency Improvement

The disposal of high-risk wells at sea has complicated problems such as complicated underground conditions,serious corrosion of pipe columns and high annulus pressure.Taking one offshore gas field as example,causes of annulus pressure were analyzed,a safety and efficient well killing technology was established.Based on cutting efficiency and result comparative analysis,efficient cuting technology for corrosion string and muti-casing was optimized,and a high efficient plugging technology for bottom strings was developed.A optimum selecting principle of well abandonment device based on economy was studied,and developed a key technology system for abandoning high risk well safety and efficiently.The field practice has proved high efficiency,low risk,low cost of this technology system,and achieved good results,for single well abandonment,the duration was saved 5 to 10 days.The technology will provide reference for abandoning domestic offshore high risk wells efficiently and economically.