基于膨胀管的井身结构拓展技术在复杂地质条件下的应用OA

The lack of Leikoupo Formation in Z203 well area of Yuxi block in the Sichuan Basin has led to unconformable contact in Xujiahe-Jialingjiang Formation,resulting in frequent lost circulation.Among them,severe lost circulation occurred when drilled into Xujiahe Formation in well Z203H5-2.Conventional chemical plugging were used 34 times but failed to solve the problem.Therefore,the expandable tube tech-nology is used to physically plug the drilling fluid loss well section.After expanding the original wellbore section to meet the conditions of the expandable tube,the pipe is inserted into the target section and the ce-menting and expansion operations are carried out.Through cement sealing at the bottom of the expandable tube and hanging sealing at the top to ensure the complete plugging of the lost well section.The field appli-cation shows that the technology can physically plug lost well section of the top Xujiahe Formation to Jia 2 member,and the formation pressure bearing capacity increased from 1.07 g/cm3 before plugging to more than 1.95 g/cm3 after,and successfully drilled to the top of Longmaxi Formation with no drilling fluid loss occurred,the well was finally completed with the original design hole size.The technology provides an effective way to deal with sudden complexity and retain the original hole size to the maximum extent.