摘要
气体钻井在我国油气田勘探开发中具有广阔的应用前景,但是川东地区多个构造实施气体钻井过程中,存在地层出水现象,严重影响了气体钻井的顺利进行,不得不改用充气钻井。充气钻井技术难点主要表现在:①井壁稳定性差,易引起垮塌卡钻;②地层出水可能与井漏同存,气液比值难以确定;③环空液柱压力降低,带砂效果差,易导致沉砂卡钻;④浅层天然气易引起井下燃爆。通过分析上述难点,结合充气钻井现场实践经验,有针对性地提出了充气钻井过程的主要技术措施:①钻井液维护处理技术;②井漏处理技术;③参数设计技术等。在川东地区3口井的现场应用效果表明:推行所提出的充气钻井技术措施,能有效避免井漏、提高机械钻速、缩短钻井周期,为川东地区遇地层出水情况下的气体钻井积累了经验。
Gas drilling has a promising prospect in hydrocarbon exploration and development in China. However, during its application in many eastern Sichuan structures, the water production out of the formations has badly affected the smooth operation of gas drilling, and in such a case, aerated drilling has to be used. This paper first presents many difficulties in aerated drilling: (1) poor wellbore stability often leads to sloughing or sticking, (2) the possible co-existence of lost circulation and water invasion makes it hard to decide the gas-to-liquid ratio of the drilling medium, (3) the cuttings carrying capability is poor due to the hydrostatic pressure decreased in the annulus, thereby resulting in sand settling sticking, and (4) downhole explosion may be easily caused by shal-low natural gas. In view of this, in combination with field practices, this paper then puts forward the major technical measures to deal with the said difficulties, including maintenance and treatment of drilling fluids, lost circulation control, and proper design of operating parameters. Through application in 3 wells in the eastern Sichuan Basin, the proposed technical measures are proved to avoid lost circulations, improve the ROP, and shorten drilling cycles, providing reference for further gas drilling in such wells when water production occurs in the eastern Sichuan Basin.
出处
《天然气工业》
EI
CAS
CSCD
北大核心
2011年第8期73-75,135-136,共3页
Natural Gas Industry
关键词
四川盆地东部
气体钻井
地层出水
充气钻井
井壁稳定
气液比
钻速
井漏
east, Sichuan Basin, gas drilling, formation water production, aerated drilling, wellbore stability, gas-liquid ratio,ROP, lost circulation
