Wells – Packers or plugs – Central support has shoulders expanding sealing portion – or...
Reexamination Certificate
1999-05-11
2001-11-20
Bagnell, David (Department: 3672)
Wells
Packers or plugs
Central support has shoulders expanding sealing portion, or...
C166S135000, C166S202000, C166S387000
Reexamination Certificate
active
06318461
ABSTRACT:
BACKGROUND OF THE INVENTION
(1). Field of the Invention
The invention is directed to an articulating anti-extrusion support system for use with a well tool including a well plug having an expandable elastomer member.
(2). Brief Description of the Prior Art
During the drilling, completion or workover of a subterranean well, it is frequently necessary to isolate one or more zones or sections of the well for various purposes. A permanent or retrievable well plug, such as a packer, bridge plug, tubing hanger assembly, or the like, will include an elastomer member for sealing across an interior area in casing or other well bore tubular previously set within the well. The elastomer member of such devices is expandable from a retracted position during run-in through the casing or open hole on a conduit member, such as tubing wire line or electric line, and are activated to seal within the well bore or casing through expansion.
The elastomeric member of the well plug may be a series of rubber-like solid seal elements which are squeezed or compressed into sealing engagement with the well casing by a compressive force generated or transmitted through the well tool.
Some such well plugs require up to 16,000 pounds of force directed through the device to impart a compressive stress in the elastomer which causes it to form the necessary hydraulic seal in the well. During the application of such high compressive forces, such elastomers do not remain static, but ooze and squeeze or otherwise result in analastic behavior, often referred to as “creep” and/or stress relaxation. After the compressive force has been applied for considerable time through such elastomer, stress relaxation through the elastomer may occur. Accordingly, well plugs which can maintain high compressive loads during deformation during the setting procedure are highly desirable. The elastomer sections, in turn, require means for resisting compressive load extrusion during the setting procedure to maximize and sustain sealing integrity. Typical of the prior art is U.S. Pat. No. 3,872,925, which teaches an expandable anchoring mechanism which includes expandable fingers for anchoring the device into the casing. A similarly designed anchoring mechanism incorporating a packer element is shown in U.S. Pat. No. 3,706,342. Likewise, U.S. Pat. No. 4,554,973 teaches the use of an elastomer support system which includes a crushable element which expands during setting to define a series of radially extending petals which overlap for support of the elastomer, but no platform or other mechanism is provided for supporting the crushable elements. A similar configuration without a support platform is disclosed in U.S. Pat. No. 5,010,958.
The present invention is directed to the problems associated with such prior art mechanisms.
SUMMARY OF THE INVENTION
The present invention is directed to the combination of a subterranean well tool which is manipulatable between a run-in condition and a set position through a well bore tubular. The tool includes a well plug component, such as a packer, bridge plug, tubing or other hanger, or similar device known to those skilled in the art and having an expandable elastomer member which seals across an interior section in the well bore.
An articulating anti-extrusion support system is provided for the well plug member and contains upper and lower articulating anti-extrusion platforms, with each of the platforms including a control mandrel having sections for transmitting a compressive load through the combination and to the elastomer. A plurality of vertically aligned cylindrical members of equal outer diameter defined during the run-in condition are provided, with each of the housing members having a bore also defined therethrough for receipt of a control mandrel portion or section.
In the preferred embodiment, a series of elongated normally retracted but outwardly pivotal supporting finger elements are provided in retracted position on one of the housing members. The finger elements are movable between retracted and extended positions and are radially disposed around the exterior of such housing members. One of the ends of the finger elements is joined to the respective housing members to permit pivoting movements of the supporting fingers between the retracted and extended positions. Anchoring means are provided to secure the system to the casing for resistance of movement through of one of the platforms and to effect relative movements between the housing members for the setting of the elastomer seal.
A series of normally collapsed platform struts are radially disposed around and are outwardly extendable with respect to the other of the housings. All of the platforms struts define one outer diameter around the housing members when the tool is in the run-in position. Each of the struts have inboard and outboard ends, with the inboard end being pivotally secured to one of the cylindrical housings to selectively permit the platform struts to expand radially outwardly. Each of the platform struts is joined at the outboard end in hinged relationship to an end of a companion supporting finger element. Each of the platform struts have a face portion which is in radial alignment toward the elastomer.
The housing members, the fingers and the struts are juxtapositioned relative to one another when the combination is in the run-in position such that the platform struts are in collapsed condition and the fingers are in retracted position resulting in the outer diameter of the fingers and the struts being no greater than the outer diameter of each of the housing members. The housing members are manipulated toward one another during activation to articulate the fingers and the struts into the set position.
Each of the articulating anti-extrusion platforms contacts and supports a series of elastomer extrusion resistors which are positioned at each of the ends of an elastomer member. Each resistor includes a plate which is positioned between its receiving platform and one end of the extruding elastomer. The plate is crushable upon manipulation of the mandrel during operation, a mandrel section extending through the plate by means of upper and lower centrally defined bores. The plate member includes a series of first and second selectively radially outwardly flexible wing elements which extend around the upper and lower bores of the plate. Each of the wing elements are severed into companion wing portions. The wing elements are secured one to another such that during crushing, the wings flex relative to one another and expand outwardly, but do not separate.
A flexible cup member is placed over each end of the exterior of the plates with a cup member having a passageway aligned with the bores of the respective plate for receipt of a mandrel section therethrough. The flexible cup member provides a series of radially expandable blade members, similar in configuration as the wing elements, for overlapping inter alignment between a plurality of the wing elements when the well tool is moved to the set position.
The face portion of each of the platforms struts will contact and support at least one of the wing and blade elements during the crushing of the plate and expansion of the elastomer member by the compressive load transmitted by the well tool with the wing and blade elements also substantially intermeshing with the elastomer member at the end thereof to resist extrusion during setting.
The anti-extrusion support system is designed to transmit maximum compressive loads through the tool and preferably impart high compressive stresses in the elastomeric member while also abating extrusion, creep and stress relaxation of the elastomer member.
The elastomer member incorporated within the present invention may be one of a number of well known configurations or, alternatively, is preferably comprised of a series of spirable elastomeric sealing rings which are stacked around the mandrel and which are compressible and outwardly expandable into helixical configuration upon application of high compressive loads transmitted by
Bagnell David
Beirner, Maynard & Parsons, LLP
Hawkins Jennifer M.
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