Method and apparatus for preventing vertical movement of subsea downhole tool string

Patent · Tue Aug 21 04:00:00 EDT 1984

OSTI ID:6418468

Taylor, Jr, J C

A method and apparatus is disclosed for eliminating vertical motion of a downhole tool in a subsea borehole as the tool is being operated by a drill string from a floating vessel. A vertical motion elimination means is incorporated into the drill string at a point which will be adjacent a blowout preventer stack on the marine bottom when the downhole tool is positioned at a desired point in the borehole. The vertical motion elimination means is comprised of a sleeve which is rotatably mounted on the drill string at a fixed vertical position. The sleeve is adapted to be engaged by the blowout preventer stack to fix the sleeve against vertical movement with respect to the preventer. Since the sleeve, itself, is fixed against vertical movement on the drill string, that portion of the drill string which lies below the preventer (hence, the downhole tool) will also be fixed against vertical motion within the borehole. However, since the drill string is rotatable with respect to the sleeve, the drill string can be rotated while the sleeve is engaged. A plurality of ports are provided in the sleeve to allow fluid circulation through the drill string while the sleeve is engaged by the blowout preventer stack.

• Assignee: Exxon Production Research Co.
• Patent Number(s): US 4466487
• OSTI ID: 6418468
• Country of Publication: United States
• Language: English

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