两口探井负压钻井的实践

PRACTICE OF UNDERBALANCED DRILLING IN 2 EXPLORATION WELLS

栗广科

Li Guangke

中原石油勘探局钻井工艺技术研究所

介绍了负压钻井的特点及施工中的注意事项。并针对高压低渗的白21井和低压易漏的毛8井钻井作业过程进行了详细的分析和对比。认为,负压钻井工艺复杂、技术含量高、施工风险大,但避免了钻进过程中对产层的损害,通过降低井内液柱压力,产生欠压实,可提高机械钻速2~6倍,延长钻头寿命2~3倍,消除压差卡钻和井漏事故的发生。

This paper introduced the characteristics of underbalanced drilling and operation cautions. Detailed analysis and comparison were made for operation processes of well Bai 21 with HP and low permeabillty and well Mao 8 with LP and leakage. The underbalanced drilling technology(UDT) is complicated, and it is a high-technical content and operation risk technology. But UDT avoided the damage to payzone during drilling. By reducing the pressure of borehole liquid column, the undercompaction was resulted in. The penetration rate can be increased by 2~6 times and the bit life can be extended by 2~3 times.The occurrence of differential sticking and lost circulation was eliminated.

10.3969/j.issn.1000-7393.1998.03.005