天东85井复杂层段钻井技术

THE DRILLING TECHNIQUE OF THE COMPLEX FORMATION IN WELL TIANDONG 85

天东 8 5井位于四川盆地川渝东部地区 ,气藏性质属于典型的碳酸盐岩储层。在同一裸眼中存在多个不同压力系统和气、漏、水等多种显示情况 ,地层压力预测难度大 ,横向上压力系统独立性强、可比性差 ,钻井难度大。该井在 2 1 5 9井眼实际钻井过程中钻遇三叠系嘉二 1组和飞仙关组 2个不同压力系统气层、二叠系长兴组以及其底部至龙潭组上部易卡层和井漏段、龙潭组上部产水等复杂地质情况 ,通过 2次调整井身结构、优化钻井技术措施 。

The well Tiandong 85 locates in the east of Sichuan basin.The character of reservoirs belongs to the typical carbonate rocks.There are multiple pressure systems and various display like gas,water layer,leakage in the same open hole;the prediction of formation pressure is difficult;the independence of horizontal pressure system is strong and the stratigraphic correlativity is poor;so it is very difficult to drill.During drilling 215.9 hole,it occured many complications.We encountered two difference pressure reservoirs in Jalingjiang and Feixianguang formation of Triassic system;also encoutered the sticking and leaking formation between Changxing and the top of lontang of Permian;and there is a water layer in the top of lontang of Permain.In despite of the complicated geological structure and the difficult drilling operation,we have adjusted the well structure for twice time and optimized drilling technique measure to handle the complicated formation.We have completed the well in the designing drilling period.