Clamping well casings
AssigneePlexus Ocean Systems Limited
InventorBernard H. vanBilderbeek
Life of this patent
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Abstract
A clamp for clamping two concentric tubes, typically two concentric tubes in an oil or gas well. The clamp has two axially movable tapered components which can be pulled over one another in an axial direction to provide a contraction of internal diameter which grips the smaller diameter tube. In one embodiment, a spacer is fitted to allow the tapered components to be held apart until the tubes have been correctly positioned. The spacer is then removed, and the tapered components are drawn together to effect the clamping. A hydraulic ram can be provided to separate the tapered components should readjustment be required. In another embodiment, the larger diameter tube is made with a relatively thin wall, so that it can be distorted inwards to grip the smaller tube.
Claims42
A releasable clamp utilized in a wellbore extending from a wellhead at the surface of the wellbore, the releasable clamp for securing an elongated, smaller tubular member positioned in the wellbore below the wellhead and having inner and outer walls and of a first outer diameter axially disposed within an elongated larger tubular member positioned in the wellbore below the wellhead having a first end, a second end, a central axis and inner and outer walls of second, larger internal diameter, the clamp comprising:
- a peripheral member having an inner diameter and an outer diameter and being disposed around the periphery of the larger tubular member below the wellhead and only between the first and second ends of both tubular members;
- a clamping device in communication with the peripheral member for generating an axial forces on said peripheral member for reducing the inner diameter of the peripheral member and thereby reducing the inner diameter of the larger tubular member for engaging and securing the smaller tubular member and for releasing said forces for disengaging the smaller tubular member.
A method for clamping an elongated, smaller tubular member disposed in a wellbore below a wellhead within an elongated, larger tubular member disposed in a wellbore below said wellhead, the method comprising the steps of:
- positioning the smaller tubular member within the larger tubular member;
- exerting a radially inward force on the exterior of the larger tubular member at a desired point below the wellhead;
- flexing the larger tubular member at the desired point inward sufficiently to cause a restriction in a portion of the inner diameter of the large tubular member at such desired point;
- causing said larger tubular member to engage said smaller tubular member at such desired point;
- and
- securing the smaller tubular member within the larger tubular member adjacent said restriction.
A releasable clamp system utilized in a wellbore extending from a wellhead at the surface of the wellbore, the releasable clamp system for securing an elongated, smaller tubular member positioned in the wellbore below the wellhead and having inner and outer walls and of a first outer diameter axially disposed within an elongated larger tubular member positioned in the wellbore below the wellhead having a first end, a second end, a central axis and inner and outer walls of second, larger internal diameter, the clamp system comprising:
- A. an elongated larger tubular member having a first end, a second end, a central axis and inner and outer walls;
- B. an elongated smaller tubular member having inner and outer walls and of a first outer diameter axially disposed within said larger tubular member;
- C. a peripheral member having an inner diameter and an outer diameter and being disposed around the periphery of the larger tubular member between the larger tubular member's first and second ends;
- D. a clamping device in communication with the peripheral member for generating an axial forces on said peripheral member for reducing the inner diameter of the peripheral member and thereby reducing the inner diameter of the larger tubular member for engaging and securing the smaller tubular member and for releasing said forces for disengaging the smaller tubular member;
- E. a restriction in said wall of said first tube adjacent the peripheral member, wherein said first tube is in contact with said second tube at the restriction.
Dependencies are inferred from the claim text.