科索1井溶洞性漏失层堵漏技术

Circulation Lost Plugging Technology in Well Kesuo 1 with Solution Cavity

溶洞性漏失层的堵漏技术是钻井过程中的难题。科索1井在钻至井深480．50m时井口失返，在历时285h，经过5次桥浆堵漏、1次注水泥堵漏和1次凝胶聚合物堵漏失败后，采用成像测井技术对漏失层的大小和位置进行了准确判断；以漏失层特征为基础，针对常规架桥封堵难以满足施工需要的实际情况，选用大的块状材料为架桥材料、可凝固材料为填充物，形成高强度、承压能力强、持久的堵塞层，成功解决了科索1井溶洞性恶性漏失的堵漏难题，形成了有流动水情况下的溶洞性井漏堵漏技术。

Plugging lost circulation in solution cavity has been considered as one of the most difficult problems during drilling. When Well Kesuo 1 was drilled to 480.50 m, loss circulation occurred with no drilling fluid returning to surface. After the failure attempts to plug using bridging fluids for five times, cementing slurry and gel polymer each for one time,image logging technique was used to identify the lost position and the size accurately. Based on the lost circulation formation characteristics and the actual situation that the conventional bridge closure cannot satisfy the implementation needs,lost circulation in Well Kesuo 1 was plugged successfully using large-size bulk materials as bridging agents and solidifiable materials as filling agents. The lost circulation technology for solution cavity with mobile water was developed.