泡沫钻井在河坝地区的应用

Application of Foam Drilling to Heba Area

针对河坝地区地层倾角大、可钻性差的特征以及钻井速度慢且存在井下漏失等技术问题,提出了在陆相地层应用充气泡沫钻井技术并从井身结构及钻井液基本配方和性能方面进行泡沫钻井优化设计。在实际应用中,泡沫钻井的平均机械钻速为常规钻井液钻井的7.6倍,大大缩短了钻井周期,还降低了单井钻井综合成本约1500万元。使用大尺寸279.4mm钻铤的塔式钻具组合,能有效施加钻压控制井斜。

Most strata in Heba area are characterized by large formation dip, resulting in poor drillability, lower penetration rate and lost circulation. In this study, foam drilling technology is proposed to be applied to the continental strata; meanwhile, optimum design of the technology is carried through based on casing program, basic formula and drilling-fluid property. In practice, the average penetration rate of foam drilling is 7.6 times higher than that of conventional drilling. Therefore, the drilling cycle may be shortened and the drilling cost of single well reduces 15,000,000 RMB yuan. Tower drilling string with a large-sized drilling collar of φ 279.4 mm can effectively impose drilling pressure and control well deviation.