Downhole casing twin-stage cone expansion device and operating method thereof

Abstract

The invention discloses a downhole casing twin-stage cone expansion device and an operating method thereof. The downhole casing twin-stage cone expansion device comprises a first-stage expansion cone,a second-stage expansion cone, a central tube, a connecting outer tube, a limiting mechanism, a top check block and the like; and the central tube is mainly composed of a spline shaft, a double-deckinner tube, a connecting inner tube and the like, and the double-deck inner tube comprises a central inner tube and a central outer tube. When an expansion casing is subjected to first-stage expansion, the first-stage expansion cone together with the connecting outer tube and the top check block move up along the central tube, and the first-stage expansion is completed after limiting displacement;when second-stage expansion occurs, the second-stage expansion cone, the central tube and the limiting mechanism move up relative to the first-stage expansion cone, and single-stroke expansion ends after second-stage limiting displacement; and hydraulic expansion of the expansion casing is completed in stages by repeating twin-stage expansion stroke until the expansion casing is fully expanded. According to the downhole casing twin-stage cone expansion device and the operating method thereof, the expansion force of the casing can be effectively reduced at downhole, the possibility of expanding the expansion casing can be achieved to a larger extent, and construction risks are reduced; and the downhole casing twin-stage cone expansion device can be used in the expansion casing operation inthe fields of expansion casing subsidy well repair, well completion, and well drilling and plugging and the like.

Description

technical field [0001] The invention relates to an expansion pipe operation device in the technical field of petroleum drilling and well completion, in particular to a downhole casing double-stage cone expansion device and an operation method. Background technique [0002] In the process of developing old oilfields, faced with problems such as difficult drilling of new wells and difficult repairing of old wells, in order to obtain the largest internal diameter, sometimes expansion casings can be used for casing subsidy and special process completion, etc. Casing repair can also be used to complete wells such as sidetracking wells and deepening wells. At the same time, when drilling in complex formations such as leakage zones, high-pressure zones, and collapsed zones during drilling, it is also a very effective way to use expansion casing to plug. Formation sealing method. However, due to the complex and changeable formation and downhole conditions, it often happens that the...

AI Technical Summary

Problems solved by technology

[0004] Aiming at the problems such as excessive expansion pressure faced by the expansion casing of the existing expansion casing, and solving the problems such as easy damage of the expansion thread caused by excessive pressure during the expansion of the downhole casing, and the risk of pressure bearing of the surface pipeline and the construction string, a new type of casing was invented. The downhole casing double-stage cone expansion device and its operation method, through the double-stage expansion cone mechanism, the expansion pipe is expanded in stages, thereby reducing the downhole expansion pressure of the casing and reducing construction risks

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