摘要
针对川西海相气藏平均井深6 000 m、岩性致密、可钻性差、多套压力系统并存等工程地质难点,沙溪庙组地层多井次压差卡钻;T3x4~T3x2二裂缝发育,井漏、井涌频繁,稳定性差;同一井眼存在多套压力体系、安全窗口窄。以海相超深井提速为目标,优化四开制井身结构,配套形成复合钻井、垂直钻井、欠平衡钻井、涡轮钻井以及钻头优选等关键技术。陆相复合钻井同比提高20%,垂直钻井提高45%、欠平衡须家河组须四段以上井段提高1.5倍,须三段井段提高62%、涡轮钻井提高85%~278%;海相优选钻头钻速与常规钻井头相当,有效进尺提高5~10倍。现场应用表明,配套集成技术应用后同比邻井相同井深的情况,平均钻速提高39.7%,缩短钻井周期170 d,节约1 200万元。
In marine gas reservoirs, western Sichuan Basin,there are many engineering and geological features, such as well depth of 6 000 m on average, tight lithology, coexistence of multiple pressure systems, and poor drillability. For many wells, differential pressure sticking may occur at the Shaximiao Formation; fractures are developed in both T3x4 and T3x2, resulting in frequent lost circulation and well kick, further poor stability; multiple pressure systems and narrow safety window appear at the same wellbore. In this study, lots of key technologies to increase drilling speed have been developed for these marine extra-deep wells, containing to optimize four- open casing program; to integrate complex drilling, vertical drilling, underbalanced drilling, and turbodrilling; and to optimize drilling bit. Consequently, drilling speed increased by 20 % after an application of non- marine complex drilling, 45 % after vertical drilling, 1.5 times above T3x4 and 62 % in T3x2 after underbalanced drilling, and 85 % to 278 % after turbodrilling, respectively. Compared with conventional drilling bit, an application of optimal one can increase the effective footage by 5 to 10 times. Their application to adjoining wells with same well depth all illustrates that after these integrated technologies, the average drilling speed increases by 39.7 %, shortening 170 d for drilling cycle, and saving RMB 12,000,000 yuan for drilling cost, individually.
出处
《天然气技术与经济》
2015年第2期41-43,79,共3页
Natural Gas Technology and Economy
基金
国家973项目课题"页岩气水平井钻完井关键基础研究"(编号:2013CB228003)的研究成果
关键词
四川
西
海相
超深井
优快钻井
钻井周期
western Sichuan Basin,marine,extra-deep wells,optimal and fast drilling,drilling cycle
