Well Ma-5 is the first underbalance well. Combined with the actual drilling situation of Well Ma-5,this paper introduces preparing work of underbalanced drilling in detail, underbalanced drilling technology and snubbing trip technology.

• 麻 5井是麻柳场构造上的第一口欠平衡钻进井 ,结合麻 5井实际钻井情况详细介绍了实施欠平衡钻井的准备工作、钻井工艺技术、起下钻工艺技术 ;