Valves are employed in many types of systems and applications for controlling fluid flow. For example, a variety of ball valves and flapper valves can be employed in subsea landing strings. Subsea landing strings may comprise various landing string components which are at least partially received within a blowout preventer stack. Once deployed, the subsea landing string may extend from within the blowout preventer stack and up to, for example, a first standard riser joint. The subsea landing string may be used to facilitate various servicing operations, including completion operations, testing operations, e.g. flow testing operations, intervention operations, and/or other well related operations. The ball valves and/or flapper valves are used to control flow, e.g. block flow, along an internal flow passage of the subsea landing string during certain stages of the operation or upon the occurrence of certain events. However, current valves utilize mechanical mechanisms with sliding or rotating surfaces which can be susceptible to damage and jamming when debris, e.g. sand, is present in the well effluent or injected fluids.
In general, a system and methodology are provided for controlling fluid flow through a component of a landing string while protecting mechanisms and/or enabling elimination of mechanisms otherwise susceptible to debris carried by fluids flowing through the landing string. A valve is provided in a well component of a landing string and comprises a flexible element. The flexible element is oriented for flexing in an inward direction with respect to an internal flow passage through the landing string. The flexible element enables selective closing off of the internal flow passage with reduced exposure of mechanical mechanisms to fluid flowing through the landing string.
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 disclosure herein generally relates to a system and methodology which facilitate control with respect to flowing fluids potentially containing debris, e.g. sand/proppant. The technique effectively protects and/or enables elimination of various mechanical valve mechanisms otherwise susceptible to detrimental effects caused by the debris. The system and methodology are useful in landing strings, e.g. subsea landing strings, and other well related equipment. The approach enables reduction in the number of mechanical components or protection of mechanical components by utilizing a flexible element for controlling, e.g. blocking, fluid flow along an internal passage of the landing string.
According to an embodiment, a valve is provided in a well component of a landing string and comprises the flexible element. By way of example, the flexible element may be in the form of a flexible tube element disposed along an internal flow passage of a landing string, e.g. a subsea landing string. The flexible tube element may be disposed within a tubular structure defining the internal flow passage and/or may comprise a section of tubing defining the internal flow passage. In this example, the flexible element is oriented for flexing in an inward direction with respect to the internal flow passage through the landing string. The flexible element may be selectively flexed to enable closing off of the internal flow passage while protecting or enabling elimination of mechanical mechanisms otherwise exposed to fluid flowing through the landing string.
Referring generally to
In the embodiment illustrated in
In some applications, the subsea landing string 24 is inserted wholly or at least partially into the BOP stack 38 to perform various well testing and/or other well service operations. It should be noted that various risers and other equipment may be employed, and one or more flexible element valve systems 22 may be used along the landing string 24. In some applications, the flexible element valve or valves 30 may be used with other types of valves disposed along the landing string 24.
Referring generally to
The flexible element 46, e.g. flexible tube element 48, may be selectively flexed in an inward direction which moves the flexible material farther into an interior of the internal flow passage 26. Accordingly, the flexible element 46 may be constructed from a variety of flexible materials, e.g. elastomeric materials of the type used for packers or other equipment subjected to the temperatures and pressures of a well related environment. However, the flexible element 46 may be constructed from various composite materials or other materials which provide suitable flexibility and strength for closing off the internal flow passage 26 in subsea and/or well related environments.
In this example, the flexible element 46 is selectively flexed inwardly via forces applied by a gate or gates 52. For example, a pair of gates 52 may be positioned on opposite sides of flexible tube element 48 and selectively shifted in a radially inward direction to close off the internal flow passage 26, as illustrated in
Depending on the application, the gates 52 may be shifted mechanically, electromechanically, hydraulically, e.g. via a hydraulic piston, or by other suitable actuator mechanisms. In some applications, the gates 52 may comprise or may work in cooperation with cutting blades 58 which can be actuated to cut coiled tubing or wireline cable if present in the wellbore 42 when valve 30 is closed. For example, the cutting blades 58 may be integrated into, e.g. coupled to, metal support gates 52 to enable shearing of a conveyance, e.g. coil tubing, wireline, or slick line, extending along the internal flow passage 26. The shearing action may be used in an emergency disconnect situation. Depending on the application, the cutting blades 58 may be constructed to extend through the flexible tube element 48 and to interlock when closed to ensure sealing of valve 30. It should also be noted that flexible tube element 48 may comprise a single tube extending between the gates 52 or, in some applications, may comprise separate tube element sections coupled to gates 52. In some embodiments, the flexible element valve system 22 may be constructed to fail to a closed position closing off internal flow passage 26 given removal of hydraulic control pressures.
Referring again to
In the embodiment illustrated, the pressure compensators 62 compensate for pressure differentials created by a low-pressure side and a high-pressure side of the gates 52. Each pressure compensator 62 may comprise a compensating bladder 64 (see
Referring generally to
The fluid pressure of fluid delivered through supply port 68 is used to inflate the flexible element 46 in an inward direction, e.g. a radially inward direction, to constrict the internal flow passage 26. As illustrated in
By placing the flexible tube element 48 along an internal surface of tubular structure 50, the flexible tube element 48 and the sealing faces are generally tangential to flows of fluid through internal flow passage 26, thus reducing the potential for erosion damage. A wear resistant support structure 72, e.g. a metal support structure, may be located within the flexible tube element 48 and/or may be embedded in the flexible tube element 48. For example, the support structure 72 may comprise a plurality of metal structures 73 embedded in or otherwise supporting the flexible tube element 48 in a region proximate sealing faces 74, which is a region susceptible to substantially erosive effects.
The metal structures 73 or other support structure 72 also may be used to provide structural support to flexible element 46 to help withstand the differential pressures across flexible element valve 30 when the flexible element 46 is closed. In some applications, the support structure 72 may comprise structures 73 in the form of a plurality of solid wedges, e.g. metal wedges, which translate into the center of the flow path defined by internal flow passage 26. Other examples of support structure 72 include braided wire or cables which are embedded in elastomeric material used to form the flexible element 46. However, various other structures and materials may be used to protect and support the flexible element 46 against erosion and differential pressures.
To accommodate inflation of flexible element 46, the flexible element 46 may be formed as flexible tube element 48 with one end affixed to the tubular structure 50 and the other end affixed to a movable, e.g. slidable, element 76. As the flexible tube element 48 is inflated, the movable element 76 is moved by the corresponding end of the flexible tube element 48 to accommodate the inward expansion of the flexible tube element, as illustrated in
The movable element 76 may be constructed in various forms to accommodate the inflation and consequent flexing of the flexible tube element 48 in an inward direction. According to an example, the movable element 76 is in the form of a slidable ring 78 which is slidably captured within a corresponding recess 80. By way of example, the corresponding recess 80 may be formed along an internal surface of tubular structure 50. The slidable ring 78 may be shifted back and forth along the corresponding recess 80 by the flexible tube element 48 as the flexible tube element 48 is inflated and deflated to close and open valve 30.
The flexible element valve system 22 may be used in many types of subsea landing strings 24, other types of landing strings, and other types of well systems. The number and location of flexible element valves 30 also may be selected according to the parameters of a given well servicing application or other application. Similarly, the size and construction of each flexible element valve 30 may be adjusted to accommodate the specific application. Various types of flexible elements 46, e.g. flexible tube elements, may be employed with corresponding actuation mechanisms, e.g. hydraulic and/or mechanical actuation systems.
The flexible element 46 is located to reduce and/or protect dynamic metal components of the overall valve system. For example, the flexible element 46 may be used to reduce the number of metal mechanical components and/or to isolate metal mechanical components. Depending on the environment and the application, the flexible element 46 may be formed from an elastomeric material, an elastomeric composite material, or other suitable materials selected according to the conditions to which the flexible element valve 30 is subjected.
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.
Number | Date | Country | |
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62240481 | Oct 2015 | US |