APPLICATION OF BELLOWS SEALING TECHNIQUE FOR WELL L7-71 IN TUHA OILFIELD

Well L7-71 encountered serious lost circulation and the drilling speed increased quickly. Many kinds of measurements have been taken for 6 times in 20 days to stop the leakage, including comprehensive sealing, the static sealing, the gel sealing, cementing sealing, however, the sealing effect is not significant. And the leakage of drilling fluid is 1007 m3. The bellows technique was developed successfully in 1990s. It can be used to settle many down-hole complicated conditions during the drilling process. Through the wellbore condition investigation, reaming hole operation, welding of the bellows, setting and hydraulic expanding the bellows and the mechanical shaping procedures, the bellows was applied in well L7-71 for the first time. The sealing effect is significant, and can be widespread deployment.