The present disclosure relates generally to equipment and operations for use in a subterranean wellbore. Example embodiments described herein include an expandable barrier device operable to prevent extrusion of a sealing element beyond the barrier device when the sealing element is set in the wellbore.
Wellbore tools such as packers, bridge plugs, etc., include a sealing element that may be employed to fluidly isolate one portion of a wellbore from another. In a hydraulic fracturing operation, for example, a bridge plug may be set to isolate portions of the wellbore that have already been fractured from portions of the wellbore that remain to be fractured. Sealing elements may also be employed for workover, drilling, production or other wellbore operations in which high differential pressures are established across the sealing element.
The sealing elements are often constructed of an elastomeric material that is squeezed or compressed into sealing engagement with a surrounding structure by a compressive force generated or transmitted through the barrier device. Some barrier devices require up to 16,000 pounds of force to impart a compressive stress in the elastomer which causes sufficient radial expansion of the elastomer to form the necessary hydraulic seal in the wellbore. Under such high compressive forces, many elastomers may not remain static, but may ooze, squeeze or otherwise be extruded into gaps defined between the barrier device and the surrounding structure. This extrusion may compromise the sealing integrity provided by the wellbore tool.
The disclosure is described in detail hereinafter, by way of example only, on the basis of examples represented in the accompanying figures, in which:
The present disclosure relates generally to a wellbore isolation tool, such as a packer, bridge plug or frac plug, that provides the ability to seal portions of a well from production or to temporarily seal zones of a well from treatment. The wellbore isolation tool may comprise a bridge plug including a sealing element supported by one or more segmented barrier devices that prohibit extrusion of the sealing element as the sealing element is subject to an axial setting force. The segmented barrier device may operate passively as segments of the barrier device are driven radially outward by the radial expansion of the sealing element and radially inward by leaf springs when the axial force is removed. Individual segments of the segmented barrier device may circumferentially overlap one another and form a generally flat shoulder for supporting the sealing element. In some embodiments, a segmented barrier device may include a jacket covering individual segments, and in some embodiments, split rings may be positioned on both axial ends of a sealing element.
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A conveyance such as wireline 16 is provided to deploy the wellbore isolation tool 100 to a desired operational position in the wellbore 12. The wireline 16 extends from a surface unit 20 through a wellhead 22 and downhole into wellbore 24. In other embodiments, the wellbore isolation tool 100 may be deployed with coiled tubing systems, slickline systems, wireline tractor systems, or any other conveyance without departing from the scope of the disclosure.
The wellbore isolation tool 100 generally includes a bridge plug 102 and a power unit 104 coupled between the bridge plug 102. The bridge plug 102 is selectively movable between a run-in-hole configuration (radially retracted) and a gripping configuration (radially extended). In the run-in-hole configuration, at least one sealing element 108 (
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The bridge plug 102 includes a generally cylindrical body 114 extending generally along a longitudinal axis A0. In some embodiments, an optional flowbore 116 may be provided along the longitudinal axis A0 to permit the passage of fluids therethrough, even when the bridge plug 102 is installed. A ball (not shown) or other mechanism may be provided to seal the flow bore 116 by seating against an upper end of the bridge plug 102 when the power unit 104 is detached. One or more slips 120 are mounted around the cylindrical body 114 and are selectively extendable and retractable with respect to the cylindrical body 114 (and extended configuration is illustrated). The slips 120 are generally operable to engage the casing string 14 (
The sealing element 108 of the bridge plug 102 is provided between a lower shoulder 124 and a segmented barrier device 126. The sealing elements 108 may be constructed materials exhibiting a high tensile strength with sufficient elongation properties to form a seal with the casing string 14. In some example embodiments, suitable materials may exhibit a tensile strength greater than 2000 psi or 3000 psi and may include materials such as cast polyurethane, molded polyurethane and fiber-reinforced nitrile. The lower shoulder 124 and the segmented barrier device 126 may be selectively approximated in an axial direction to cause a radial expansion of the sealing element 108. For example, in some embodiments, the power unit 104 may be operable to impart an axial tensile force to a mandrel 130 (see
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Each of the segments 132 is coupled to a housing 146 of the segmented barrier device 126 by a biasing member 148. In the embodiment illustrated in
As indicated above, the bridge plug 102 may be transitioned to the expanded configuration of
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At step 406, the sealing element is radially expanded in response to the axial force and the axial approximation of the segmented barrier device and the shoulder. The radial expansion of the sealing element drives the segments of the segmented barrier device radially outward with a radial force imparted by the sealing element. The sealing element also applies an axial force to the segments which, together with the radial force, may cause the segments to pivot over an edge of a housing of the tool so as to engage the surrounding structure with a sharp corner on the segments (step 410).
At step 412, the power unit may be detached from the segmented barrier device and wellbore operations may be conducted in the wellbore. For example, hydraulic fracturing operations may be conducted in a wellbore zone on an opposite side of the sealing element from the segmented barrier device. The segmented barrier device supports the sealing element against an increased pressure in the wellbore zone being hydraulically fractured and prevents extrusion of the sealing element beyond the segments. An effective seal is thus maintained and damage to the sealing element is prevented.
At step 412, once the wellbore operations are complete, the power unit may be returned to the wellbore tool and reconnected. A signal may be transmitted to the power unit to relieve the axial force from the sealing element to permit the sealing element to return a radially retracted configuration spaced from the wellbore wall. The leaf springs or other biasing members then drive the segments radially inward toward the housing (step 416). With the sealing element and segmented barrier device in the radially retracted configuration, wellbore tool may be moved with the conveyance to another location in the wellbore or removed (step 418.
The aspects of the disclosure described below are provided to describe a selection of concepts in a simplified form that are described in greater detail above. This section is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter.
According to one aspect, the disclosure is directed to a wellbore isolation tool that includes a mandrel defining a longitudinal axis, and a sealing element disposed about the mandrel and having a first and second axially-facing compression surfaces. The sealing element is elastically deformable to expand radially outward in response to an axial compression force applied between the compression surfaces. The wellbore isolation tool also includes a segmented barrier device having an abutment surface in direct contact with the first compression surface of the sealing element, the segmented barrier device including a plurality of circumferentially overlapping segments defining a continuous and complete circular profile around the mandrel, wherein the plurality of overlapping segments expand radially outward in response to radial expansion of the sealing element.
In one or more embodiments, each segment of the segmented barrier device is pivotally coupled to a housing such that each segment pivots radially outward in response to the radial expansion of the sealing element. Each segment of the segmented barrier device may include an outer circumferential edge of the abutment surface defining a sharp corner for engaging a surrounding structure.
In some embodiments, the wellbore isolation tool further includes a plurality of elongated biasing members coupled between the housing and the plurality of segments, each biasing member biasing a respective segment to a radially retracted position with respect to the housing. Each of the elongated biasing members may be seated within an elongated recess formed in the housing.
In one or more embodiments, the wellbore isolation tool further includes a jacket formed over the plurality of overlapping segments, the jacket covering circumferential gaps defined between adjacent segments of the plurality of segments. The jacket may be constructed of a non-metallic material including at least one of the group consisting of fractioned rubber, carbon fiber and fiberglass. In some embodiments, the jacket is constructed of a metallic material including at least one of the group consisting of stainless steel, an austenitic nickel-chromium-based alloys and brass. The wellbore isolation tool may further include a second segmented barrier device in contact with the second compression surface of the sealing element.
According to another aspect, a wellbore isolation system includes a power unit having a connector at an upper end thereof for coupling the power unit to a wellbore conveyance. A mandrel defines a longitudinal axis and is operably coupled a lower end of the power unit. The mandrel is operable to receive an axial force from the power unit and to impart the axial force to a body defining a shoulder thereon. A segmented barrier device has an abutment surface defined on a plurality of circumferentially overlapping segments, and the segments define a continuous and complete circular profile around the mandrel. A sealing element is disposed about the mandrel and axially between the segmented barrier device and the body. The sealing element has a first compression surface in contact with the abutment surface of the segmented barrier device and a second compression surface in contact with the shoulder of the body. The sealing element is deformable to expand radially outward in response to the axial force applied between the compression surfaces and to drive the segments of the segmented barrier device radially outward.
In one or more embodiments, the power unit is selectively detachable from a housing coupled to the segmented barrier device. Each segment of the plurality of segments may be pivotally coupled to the housing, n some embodiments, the wellbore isolation system further includes a plurality of biasing members coupled to the plurality of segments to bias the plurality of segments to a radially retracted configuration with respect to the housing.
In some embodiments, z-shaped gaps may be defined between each segment of the plurality of segments. The wellbore isolation system may further include a plurality of slips operably coupled to the power unit for selective extension from the body. In some embodiments, the wellbore isolation system further includes a wireline coupled the connector of the power unit.
In another aspect, the disclosure is directed to a method of deploying and operating a wellbore isolation tool. The method includes (a) running wellbore isolation tool into a wellbore on a conveyance, (b) signaling a power unit carried by the wellbore isolation tool to radially expand a sealing element into engagement with a surrounding structure in the wellbore, (c) driving a plurality segments of a segmented barrier device radially outward in response to the radial expansion of the sealing element, the plurality of segments defining a complete circumferential profile and (d) engaging an inner surface of the surrounding structure with the segments to prohibit extrusion of the sealing element past the segmented barrier device.
In some embodiments, driving the plurality of segments radially outward includes pivoting the plurality of segments. The method may further include signaling the power unit to permit the sealing element to radially retract and to permit each segment of the plurality of segments to return to a radially retracted configuration under a bias from a biasing member. In some embodiments, the method further includes pressurizing a wellbore zone on an opposite side of the sealing element from the segmented barrier device.
The Abstract of the disclosure is solely for providing the United States Patent and. Trademark Office and the public at large with a way by which to determine quickly from a cursory reading the nature and gist of technical disclosure, and it represents solely one or more examples.
While various examples have been illustrated in detail, the disclosure is not limited to the examples shown. Modifications and adaptations of the above examples may occur to those skilled in the art. Such modifications and adaptations are in the scope of the disclosure.