Back milling tool and method of clearing a bottom end plug assembly under an expanded tube
The reverse milling tool solves the problem of the sealing component rotating during the milling process by combining a channel grinding shoe and an extended cutting tool, thus achieving efficient removal of the bottom sealing component below the expansion tube.
CN122447019APending Publication Date: 2026-07-24CNPC GREATWALL DRILLING COMPANY +1
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Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- CNPC GREATWALL DRILLING COMPANY
- Filing Date
- 2025-01-22
- Publication Date
- 2026-07-24
AI Technical Summary
Technical Problem
Existing milling tools often cause the bottom sealing component to rotate when removing the expansion tube, resulting in low removal efficiency.
Method used
Using a reverse milling tool, the bottom sealing component is first ground through by a channel milling shoe, and then the blade at the protruding position is used for reverse milling to ensure that the connection between the sealing component and the expansion tube is not cut off, thus achieving efficient removal.
Benefits of technology
It achieves efficient removal of the bottom sealing component, avoids the problems caused by the sealing component rotating during the milling process, and improves the efficiency of milling operations.
✦ Generated by Eureka AI based on patent content.
Smart Images
Figure CN122447019A_ABST
Abstract
The application discloses a back milling tool and a method for removing a bottom end blocking assembly under an expanded pipe, the back milling tool is connected with a drill rod and comprises an upper joint, a blade mounting seat, a through-channel grinding shoe, a piston and a plurality of blades, the upper end of the upper joint is connected with the drill rod, the upper joint, the blade mounting seat and the through-channel grinding shoe are all in a cylindrical structure and are fixedly connected in sequence, a plurality of mounting holes are formed in the circumferential direction of the blade mounting seat, the bottom ends of the plurality of blades are rotatably mounted in the mounting holes respectively to switch between an extended position and a retracted position; the piston is a cylindrical structure and can slide along the axial direction of the upper joint, the outer side wall of the piston is provided with a first taper surface, and the top end of the blade is provided with a first inclined surface; when the drill rod passes the drilling fluid with a pressure greater than or equal to a preset pressure threshold value to the back milling tool, the back milling tool rotates along with the drill rod, the piston slides downward along the axial direction of the upper joint to drive the first taper surface and the first inclined surface to slide in contact to drive the plurality of blades to rotate to the extended position.
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