Patent Application
20180154498
Hydrocarbon fluids such as oil and natural gas are obtained from a subterranean geologic formation, referred to as a reservoir, by drilling a well that penetrates the hydrocarbon-bearing geologic formation. The well may be drilled at the surface or at a subsea location and the flow of fluids may be handled by several different types of equipment. In subsea operations, for example, a subsea tree may be mounted to a wellhead such that a tubular flow path is provided within the subsea tree. Various components along the tubular flow path may be joined and sealed with respect to each other via a seal or seals. If disruptions occur with respect to the seal, however, leakage can result.
In general, systems and methodologies are described for sealing or resealing an interface between parts and/or repairing a defective location along a component, e.g. along a pressure vessel or a pressure flow path of a component. A burnishing assembly is used to form a plastically deformed region along an internal surface, e.g. an internal metal surface. The plastically deformed region may be located to create a seal. The burnishing assembly may comprise a stem sized for insertion into a tubular region. The stem may be combined with an actuator and a plurality of rolling elements mounted on the actuator. When the actuator is actuated to a radially outward position, the plurality of rolling elements is moved into engagement with the internal surface until plastic deformation occurs. The stem may then be rotated to force the plurality of rolling elements along the internal surface so as to form a region of plastic deformation. The plastic deformation may be formed as a ring positioned to create, for example, a seal between adjacent components.
However, many modifications are possible without materially departing from the teachings of this disclosure. Accordingly, such modifications are intended to be included within the scope of this disclosure as defined in the claims.
Certain embodiments of the disclosure will hereafter be described with reference to the accompanying drawings, wherein like reference numerals denote like elements. It should be understood, however, that the accompanying figures illustrate the various implementations described herein and are not meant to limit the scope of various technologies described herein, and:
In the following description, numerous details are set forth to provide an understanding of some embodiments of the present disclosure. However, it will be understood by those of ordinary skill in the art that the system and/or methodology may be practiced without these details and that numerous variations or modifications from the described embodiments may be possible.
The present disclosure generally relates to a methodology and system which utilize a burnishing assembly, e.g. a sealing assembly, to provide controlled plastic deformation along an interior wall surface. The burnishing assembly enables formation of a seal via plastic deformation of an internal surface, e.g. an internal metal surface. For a sealing application, for example, the burnishing assembly may be inserted into a tubular region within a structure and then actuated to form a region of plastic deformation. The plastic deformation may be positioned to establish a seal between, for example, adjacent components.
According to an embodiment, the sealing assembly comprises a stem, e.g. a mandrel, sized for insertion into the tubular region, e.g into a tubular region within a subsea tree, a pipeline, a flow conduit, a manifold, a pressure vessel, or another component. The stem may be combined with an actuator and a plurality of rolling elements mounted on the actuator. When the actuator is actuated to a radially outward position, the plurality of rolling elements is moved into engagement with an internal surface (defining the tubular region) until plastic deformation occurs. The stem may then be rotated to force the plurality of rolling elements along the internal surface so as to form a ring of plastic deformation.
The plastic deformation may be located and oriented to form a seal between adjacent components. In some applications, the stem also may be moved longitudinally during rotation to form a wider ring of plastic deformation along the seal region. The rolling elements may be in the form of ball elements, cylindrical elements, or other suitable rolling elements able to form the desired plastic deformation when sufficient force is applied via the actuator.
In an operational example, the sealing assembly may be sized for insertion into a subsea tree to address leakage at an outlet flange of a choke on the subsea tree. In such an application, the sealing assembly is actuated to a radially contracted configuration for movement through the smaller diameter of a bore restriction and then into position within the subsea tree at the outlet flange of the production choke. Once in position, the sealing assembly may be actuated to a radially outward or expanded configuration which forces the rolling elements into engagement with the inner metal wall surface of the subsea tree at the outlet flange of the production choke.
Sufficient force is applied by the actuator to cause the plurality of rolling elements to plastically deform the inner metal wall surface. The stem is then rotated so the rolling elements are able to form a ring of plastic deformation along this inner metal wall surface. The ring of plastic deformation may be located to form a continuous metal surface across the connection between the choke body flange and an adjacent mating flange. The deformation of the metal material across this connection effectively forms a seal between the adjacent components where a leak path might otherwise reside. In some applications, the stem may be moved longitudinally while rotated to create a wider ring of plastic deformation so as to ensure creation of the seal between adjacent components.
Referring generally to
In the embodiment illustrated, the sealing assembly 20 comprises a plurality of rolling elements 28 mounted on an actuator 30 which, in turn, may be mounted on a rotatable stem 32, e.g. a rotatable mandrel. The rolling elements 28 may comprise ball elements 34, as illustrated, or they may comprise other suitable rolling elements. For example, the rolling elements 28 may comprise variously shaped rollers or other elements able to apply localized pressure so as to cause controlled plastic deformation of the interior surface 26.
According to an embodiment, the actuator 30 comprises at least one piston 36 on which the rolling elements 28 are mounted. Each piston 36 may be slidably mounted within a corresponding passage 38 formed within stem 32. An appropriate seal or seals 40, e.g. O-ring seals, may be used between each piston 36 and the surrounding wall surface of corresponding passage 38.
In the embodiment illustrated, the actuator 30 may comprise a pair of opposed pistons 36 which are both slidably received in the corresponding passage 38 for actuation between a radially inward position and a radially outward, engaged position. In
Referring again to the embodiment of
During a sealing operation, for example, the sealing assembly 20 is moved via a suitable conveyance and into the interior of the overall component 22 along the tubular interior 24. In some embodiments, the sealing assembly 20 is moved along the interior surface 26, e.g. interior metal surface, until the rolling elements 28 are located proximate a desired seal area 48. Once at the desired seal area 48, the actuator 30, e.g. one or more pistons 36, is actuated to move the plurality of rolling elements 28 into engagement with interior surface 26 at seal area 48. The rolling elements 28 are moved with sufficient force to plastically deform the interior surface 26.
The stem 32, e.g. mandrel, is then rotated so the plurality of rolling elements 28 move along interior surface 26 and create a region, e.g. ring, of plastic deformation along the interior surface 26. For example, the stem 32 may be rotated at least 360° to form a circumferential ring extending along the interior of component 22 throughout the entire circumference surrounding tubular interior 24. When the plurality of rolling elements 28 is initially forced into interior surface 26, the externally located rolling elements 28 cause the initial plastic deformation. For example, one, two, three, or more of the rolling elements 28 may cause the initial plastic deformation but sequential rolling elements 28 of each set of rolling elements are moved into engagement with interior surface 26 as the stem 32 is rotated. During rotation of stem 32, the rolling elements 28 are able to rotate within carrier recess 44 and roll along interior surface 26, thus forming the overall ring of plastic deformation. In some applications, the sealing assembly 20 may be moved in a longitudinal direction during rotation of stem 32 through several rotations to create a wider ring of plastic deformation in the form of, for example, a helix, as described in greater detail below.
The actuator 30, e.g. one or more pistons 36, may be biased toward the radially retracted position via a suitable biasing mechanism 49. The biasing mechanism 49 ensures the actuator 30 is retracted back to its radially contracted position following formation of the desired plastic deformation along interior surface 26. By way of example, the biasing mechanism 49 may comprise a spring or springs coupled between pistons 36. The spring(s) draws pistons 36 radially inward after the force actuating pistons 36 to the radially outward, engaged position is reduced. However, external pressures, camming action of a change in diameter along interior surface 26, or other mechanisms or techniques may be used to transition the actuator 30 back from a radially extended position to a radially contracted position to facilitate removal of sealing assembly 20 from component 22.
Referring generally to
In this example, the subsea components 50, 52 include tubular interior 24 defined by interior metal surface 26. In some applications, the subsea components 50, 52 may include a thin layer of weld overlay 60 positioned along tubular interior 24 and defining interior metal surface 26. The weld overlay or other material forming interior surface 26 may be a metal material sufficiently malleable to enable a desired displacement of material during the plastic deformation to create a metal seal along the joint between component 50 and component 52.
Depending on the application, the subsea component 50, e.g. the upper component, may have a radially constricted region 62 along tubular interior 24. Accordingly, the sealing assembly 20 is deployed down into component 22 (subsea components 50, 52) with the actuator 30, e.g. one or more pistons 36, in the radially contracted position illustrated on the left side of
Once the plurality of rolling elements 28 is at the desired seal area 48, the actuator 30, e.g. pistons 36, may be actuated to the radially extended position illustrated on the right side of
When the actuator 30 is transitioned to the radially extended position, the plurality of rolling elements 28 is moved into engagement with interior surface 26 to cause a plastic deformation 68, as further illustrated in
In the specific embodiment illustrated in
Referring generally to
To facilitate use with a subsea component, e.g. subsea tree 74, the sealing assembly 20 may comprise an anti-rotation sleeve 76 through which stem 32 rotatably extends. In this example, the anti-rotation sleeve 76 comprises anti-rotation pins 78 which may be releasably mounted with respect to the anti-rotation sleeve 76 via snap rings 80 or other suitable fasteners. The anti-rotation pins 78 are positioned for receipt in corresponding recesses 82 of subsea tree 74, e.g. of choke body 75.
The anti-rotation sleeve 76 also may comprise a hot stab receptacle 84 positioned for operative engagement with a remotely operated vehicle (ROV) to enable application of hydraulic pressure to pistons 36 via hydraulic passage 64. The hot stab receptacle 84 be placed in fluid communication with hydraulic passage 64 via a corresponding hydraulic passage 86 extending into fluid engagement with hydraulic passage 64 via transverse hydraulic flow channels 88 located between seals 90 positioned along stem 32 as illustrated.
In this example, stem 32 is coupled with a drive extension 92 appropriately constructed for engagement by the torque drive of an ROV. This allows the stem 32 to be selectively rotated via an ROV deployed to the subsea tree 74. In some applications, a torque bucket 94 may be positioned over drive extension 92 and secured to anti-rotation sleeve 76 by suitable fasteners 96, e.g. screws. The torque bucket 94 may be structured for coupling with the ROV to facilitate rotation of the drive extension 92.
The sealing assembly 20 also may comprise a mechanism 98 for providing longitudinal motion of stem 32. By way of example, mechanism 98 may comprise a threaded region 100 located between stem 32 and the surrounding anti-rotation sleeve 76. Because the stem 32 and anti-rotation sleeve 76 are threadably engaged, rotation of stem 32 while anti-rotation sleeve 76 is rotationally constrained via anti-rotation pin 78 forces stem 32 to move in a longitudinal direction.
Longitudinal movement of stem 32 relative to drive extension 92 may be accommodated via slidable drive splines 102. Additionally, the longitudinal movement of stem 32 relative to anti-rotation sleeve 76 may be restricted via a suitable mechanism, such as a retainer plate 104 secured to anti-rotation sleeve 76 via suitable fasteners 106. In this example, the retainer plate 104 is slidably captured in a corresponding annular stem recess 108, thus limiting the overall longitudinal movement of stem 32 relative to anti-rotation sleeve 76.
The embodiment illustrated in
During a sealing operation, the sealing assembly 20 is lowered over the choke body 75 and the downwardly oriented anti-rotation pins 78 are moved into engagement with corresponding recesses 82. The ROV is then engaged with drive extension 92 located in torque bucket 94 and operated to rotate the drive extension 92 in the appropriate direction until the anti-rotation sleeve 76 begins to lift from the choke body 75. This means the sealing assembly 20 is positioned in a fully down position (see left side of
The ROV is then operated to apply pressure through hot stab receptacle 84 and down through hydraulic fluid flow passage 64 so as to drive pistons 36 in the radially outward direction. The pistons 36 are moved to the radially extended position such that the harder rolling elements 28 are forced into the softer interior surface 26 to cause the plastic deformation 68. An operator of the ROV then causes the ROV to rotate drive extension 92 and thus stem 32 in an opposite direction while maintaining sufficient pressure via hot stab receptacle 84 to maintain pistons 36 in the radially extended position.
As the stem 32 is rotated, threaded region 100 causes the stem 32 to move longitudinally and to advance in an upward direction. This rotational and longitudinal movement causes the desired wide, ring of plastic deformation 70 across the joint/connection region between flanges 54 and 56. Rotation of the stem 32 may be continued until halted via retainer plate 104 stopping against the edge of annular stem recess 108. When the retainer plate 104 engages the edge of annular stem recess 108, a sudden increase in torque occurs and the increase can be detected by an operator. In some applications, the operator may reverse the rotational direction so as to move the stem 32 and rolling elements 28 back down along the ring of plastic deformation 70.
Depending on the specifics of a given burnishing application, the components of burnishing/sealing assembly 20 may vary. Additionally, the assembly 20 may be used in a variety of subsea applications and other applications to enable burnishing of material along internal surfaces of many types of components. The size, shape, and type of components utilized in assembly 20 may be selected according to the parameters of the operation. For example, the assembly 20 may utilize various types of actuators, including inflatable actuators, pivoting actuators, single piston actuators, multiple piston actuators, and other suitable types of actuators. The actuators also may be driven hydraulically, electrically, mechanically, or by other suitable techniques to provide the desired force for driving the rolling elements into the material of the interior surface 26. Various types of rolling elements 28 also may be selected to provide a desired plastic deformation at a desired depth during movement of stem 32.
Although a few embodiments of the disclosure have been described in detail above, those of ordinary skill in the art will readily appreciate that many modifications are possible without materially departing from the teachings of this disclosure. Accordingly, such modifications are intended to be included within the scope of this disclosure as defined in the claims.
