井下隔离法全过程欠平衡钻井技术及应用

全过程欠平衡技术是指在不压井的条件下实现欠平衡钻进、不压井起下钻具、电测仪器、完井管具等。井下隔离技术是利用套管阀将井下的油气和压力封隔在阀板以下，是目前最实用的一种不压井作业技术。因此,决定在胜利油田渤深6-13井采用该技术。在详细分析全过程欠平衡技术特点和技术关键的基础上，根据渤深6潜山的地质情况，结合该区块欠平衡作业的经验，针对该井制定了不压井作业施工方案，配套完善了欠平衡装备和工具，对施工人员进行了技术培训，最终利用井下套管阀成功地实施了从钻进到下筛管的全过程欠平衡作业。

To Realize Whole-process Underbalanced Drilling through Adoption of Downhole Isolation Method and Field Application

Whole-process underbalanced drilling technology is to perform underbalanced drilling, snubbing in or out drilling tools, logging tools and completion strings into a live well without killing the well. The downhole isolation technology is to use downhole isolation valve to isolate the oil/gas and downhole pressure below the valve, which is currently the most practical snubbing technique. Therefore a decision was made to apply this technology on Well Boshen 6-13 in Shengli oilfield. A detailed analysis was made regarding the characteristics and the critical technical issues of underbalanced drilling, the geologic conditions of the buried mountain Boshen 6 and the experiences of underbalanced drilling in this area were taken into consideration. An underbalanced operation plan was then made, the corresponding equipment and tools were got ready, and special technical training was conducted to operators. The downhole isolation valve has finally been successfully used in the whole-process underbalanced drilling, from drilling to screen pipe running.