In subsea operations, 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. Subsea equipment is positioned at the well and may comprise a wellhead and a blowout preventer. A riser may be deployed between the subsea equipment and a surface facility, e.g. a surface vessel. A subsea landing string system may be deployed down through the riser and into the subsea equipment to provide hydraulic controls over various tools and safety features. For example, the subsea landing string system may comprise a subsea control module which actuates directional control valves based on control signals sent from the surface.
The directional control valves are part of an electro-hydraulic system and may be solenoid piloted according to control signals. Based on the control signals, the directional control valves are actuated so as to direct hydraulic actuating fluid to appropriate tools or other features. The solenoids and directional control valves are housed in manifolds mounted inside a dielectric fluid compensated enclosure to prevent exposure to seawater which can cause shorting of the solenoids. Due to the compensated enclosure, large compensators are used which tends to make the overall subsea landing string system larger in size. The compensated enclosure also prevents direct access to the directional control valves which increases the difficulty of servicing and troubleshooting the subsea landing string system. Additionally, the dielectric fluid compensated enclosure and corresponding compensators are vacuum filled which can increase the time involved with both assembly and service of the subsea landing string system.
In general, a system and methodology are provided which enable construction and operation of a subsea landing string system having a system manifold or manifolds unprotected by a dielectric fluid compensated enclosure. The manifolds contain directional control valves and corresponding solenoids which are able to operate while being exposed to environmental fluids such as seawater. The ability to operate manifolds in an unprotected environment enables the manifolds to be positioned in a variety of locations along the subsea landing string system or in cooperation with the subsea landing string system. The subsea landing string system may be a modular system in which manifolds are added, removed or adjusted according to the parameters of a given operation. The system modularity can greatly reduce tool downtime and provide greater flexibility to meeting changing client needs.
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 system and methodology which facilitate construction and operation of a subsea landing string system having a ruggedized system manifold or manifolds. According to embodiments, the ruggedized manifold system is unprotected by a dielectric fluid compensated enclosure. The approach enables use of the subsea landing string system while the manifolds are exposed to seawater or other environmental fluids, such as fluids contained within a riser. Because the manifolds are not sealed within a compensated enclosure containing dielectric fluid, the overall structure of the subsea landing string system may be modular. In other words, the subsea landing string system may be constructed with manifold attachment regions which allow manifolds to be added and removed according to the parameters of a given operation.
In some embodiments, the subsea landing string system may be constructed such that sections of the landing string and corresponding manifolds may be added, removed or adjusted, effectively making the system larger or smaller as desired. Because the manifolds may be exposed to surrounding environmental fluids, the modular system is enabled and may be modified as desired for each job. The system modularity can greatly reduce tool downtime in various applications. For example, the modularity enables greater accessibility which results in easier maintenance and troubleshooting. The greater accessibility also allows the system to be easily modified between jobs to comply changing client needs of a specific job. The manifolds may have valves, control board, sensors, wiring schemes, communication architecture, and/or other features which help achieve a desired modularity.
According to an embodiment, the manifolds contain directional control valves and corresponding solenoids which are able to operate while being exposed to environmental fluids such as seawater. The ability to operate manifolds in an unprotected environment enables the manifolds to be positioned in a variety of locations along the subsea landing string system. Depending on parameters of a given subsea operation, the manifolds may be positioned separate from the landing string and used in cooperation with the subsea landing string system.
In some embodiments, each manifold may contain or work in cooperation with a manifold electronic module, e.g. an electronics board, and may also contain sensors, e.g. pressure gauges. The manifolds can be completely self contained hydraulic control and monitoring packages. Wiring and electrical terminations may be protected from environmental fluid, e.g. external riser fluid, by various approaches. The electronic board associated with each manifold provides signals/commands to actuate the solenoids which, in turn, actuate the corresponding directional control valves. A separate subsea electronic module (SEM) may be operatively coupled with the electronic boards to provide commands to the individual electronic boards for each manifold.
The electrical architecture may be constructed according to various methodologies such as a multidrop architecture in which multiple nodes are connected on the same bus. Such an approach enables connection of the manifolds via daisy-chaining techniques or other suitable techniques. This technique significantly reduces the number of electrical connections thereby significantly increasing the overall reliability of the system.
The modularity of the subsea landing string system enables functional expansion of the system without loss of system reliability. Additionally, the modularity enables changes between jobs to meet the parameters for a given operation. For example, the types of manifolds may be changed, e.g. high pressure rated manifolds may be substituted for low pressure rated manifolds or manifolds with different directional control valves may be added or substituted. The overall system is simpler and less expensive due to the ability to provide manifolds which are not sealed within a compensated dielectric chamber.
Additionally, the modularity provides a system which is easier to service, thus reducing service downtime. The modularity also enables manifolds to be located on other assets or at other positions in the overall landing string instead of being restricted to the subsea landing string system. Furthermore, the approach facilitates more rapid and precise control of, for example, a subsea test tree and associate valves while also enabling a quicker emergency shutdown.
Referring generally to
By way of example, the subsea system 30 may comprise at least one well 32 having a wellbore 34 extending into a subsea geologic formation 36. An upper end of the wellbore 34 is in fluid communication with a wellhead installation 38 positioned proximate a sea floor 40. The wellhead installation 38 may comprise various types of equipment, such as a wellhead system 42 (which may include a Christmas tree) and a blowout preventer 44 positioned above the wellhead system 42.
In the example illustrated, a riser 46 extends between the wellhead installation 38 and a surface facility 48, e.g. a surface vessel, located at a sea surface 50. The riser 46 may be filled with an environmental fluid 52 which may comprise seawater or other riser fluids. A subsea landing string system 54 is deployed down through the riser 46 and into the blowout preventer 44. As with conventional subsea landing string systems, the illustrated subsea landing string system 54 may comprise various valves and latches which enable shutdown of well flow and separation of the landing string when the blowout preventer 44 is actuated in an emergency shutdown situation. The subsea landing string system 54 may be conveyed down to the wellhead installation 38 via an appropriate conveyance 56, e.g. coil tubing. In some embodiments, the subsea landing string system 54 may be used without riser 46 such that the subsea landing string system 54 is deployed through environmental fluid 52 in the form of open seawater.
Referring generally to
According to the embodiment illustrated, the accumulator section 58 is connected to a hydraulic valve and manifold pod section 68. In some embodiments, the hydraulic valve and manifold pod section 68 also is the section which contains the conventional flow control valves and latches actuated in the event of an emergency shutdown. In some applications, the valves may be in a separate module, e.g. a separate module located below pod section 68. Additionally, the pod section 68 may contain at least one and often a plurality of manifolds 70 which may be individually controlled via a subsea electronic module (SEM) 72.
In this example, the subsea landing string system 54 is in the form of a modular landing string which allows individual manifolds 70 to be added or removed from corresponding manifold mounting sites 74 positioned along a landing string structure 76, e.g. a landing string chassis. In some embodiments, the landing string structure 76 also may be constructed via assembly of separable landing string sections 78 having corresponding manifold mounting sites 74. With either type of configuration, the number of manifolds 70 may be increased or decreased according to the parameters of a given subsea operation and according to the types and numbers of tools 64 utilized in the subsea operation.
Referring generally to
Each solenoid 84 is coupled with at least one solenoid control line 86, e.g. at least one electrical control wire, by which the solenoid 84 receives commands from SEM 72. The at least one control line 86 may be routed through the manifold body 80 and sealed with respect to the environmental fluids 52 surrounding the manifold body 80. As described in greater detail below, the commands to each solenoid 84 may actually be received from a corresponding manifold electronics module which, in turn, receives commands from the SEM 72. According to those commands, the appropriate solenoids 84 are actuated to block or allow flow of actuating fluid 62 to and/or from the appropriate tool or tools 64. The tools 64 may include ball valves, slide valves, latches, and other tools disposed within the subsea landing string system 54 as well as tools external to the landing string system 54.
Referring generally to
The solenoid 84 also comprises a solenoid valve actuator body 100 which is positioned for engagement with the corresponding directional control valve 82 so as to shift the directional control valve 82 in a desired direction when the solenoid 84 is actuated. By way of example, the solenoid valve actuator body 100 may comprise or be in the form of a plunger moved linearly upon actuation of the solenoid 84 so as to rotate or otherwise actuate the corresponding directional control valve 82. According to an embodiment, a seal, e.g. a multi-seal, may be placed along valve actuator body 100. In some embodiments, the solenoid operated valves may be in the form of hydraulic pilots coupled with directional control valves 82. Additionally, the solenoid 84 may comprise a locating pin 102 or other suitable feature positioned to properly locate and orient the solenoid 84 when positioned in recess 88 of manifold body 80. In some embodiments, the locating pin 102 ensures proper valve port orientation of the corresponding directional control valve 82.
To avoid exposure to environmental fluid 52, the at least one solenoid control line 86, e.g. electrical wire, is routed through the manifold body 80, e.g. through a hole in the manifold body 80, and operatively connected to the solenoid 84 in a sealed region 104. The seals used to establish sealed region 104 and/or the multi-seal along actuator body 100 are formed from seal materials selected to survive in the fluid and pressure environments in which the manifold system is operated. By way of example, a seal 106, e.g. an O-ring seal or other suitable seal, may be positioned around the solenoid body 96 between the solenoid 84 and a surrounding recess surface 108 of manifold body 80 to form the seal region 104. Similar O-ring seals, other seals, or combinations of seals may be used along valve actuator body 100.
A solenoid ground wire 110 also may be connected with solenoid 84 within sealed region 104 and further connected to a suitable internal ground. For example, the solenoid ground wire 110 may be coupled with locating pin 102 (see
Referring generally to
In this example, the solenoid ground wire 110 may be connected internally, e.g. connected with locating pin 102, or routed to subsea connector 114 for connection with a corresponding ground wire. This approach enables a reduction in the number of wires routed through the manifold 70. The manifold body 80 effectively serves as the ground via ground wire 110, and the manifold electronic board also may be grounded to manifold body 80 to complete the circuit. In some embodiments, more than one solenoid 84 may be interfaced with a single subsea connector 114 to reduce the number of parts.
Referring generally to
In the embodiment illustrated in
In other embodiments, each solenoid 84 may be connected with a plurality of wire sets, e.g. two sets of solenoid control lines 86 and ground wires 110, as illustrated in
Referring generally to
Actuation of selected, individual solenoids 84 may be controlled by a manifold electronics module 126 which may be in the form of a printed circuit board or other suitable manifold electronic board. In this example, the manifold electronics module 126 is disposed within manifold body 80 and sealed therewithin. The solenoid control lines 86, e.g. electrical wires, may be routed from each solenoid 84 and each corresponding sealed region 104 to the manifold electronics module 126 via channels 112 or via other suitable methods.
In some embodiments, the manifolds 70 also may comprise sensors 128, e.g. pressure gauges, to monitor desired functions. For example, the sensors/pressure gauges 128 may be positioned to monitor pressures along channels within flow network 122 so as to verify actuation of specific directional control valves 82 via the corresponding solenoids 84. It should be noted the sensors 128 also can be part of the manifold electronics module 126. The data from sensors 128 may be provided to manifold electronics module 126 via corresponding signal lines (similar to solenoid control lines 86) which are sealed within the body 80 of manifold 70. Furthermore, the manifold electronics module 126 may be placed in communication with the subsea electronics module 72 and/or other manifolds 70 via subsea tolerant cables 130. The subsea tolerant cables 130 may comprise sealing connectors 132, e.g. dry mate or wet mate connectors, operatively plugged into the subsea electronics module 72 and/or cooperating manifolds 70.
As illustrated in
Referring generally to
In some embodiments, an individual manifold electronics module 126 may provide instructions for a plurality of manifolds 70. As illustrated in
According to another embodiment, a group of manifolds 70 may be wired to the subsea electronics module 72 via subsea tolerant cables 130, as illustrated in
In another example, the manifold electronics module 126 itself or the separate module 136 containing manifold electronics module 126 may be joined with a junction box 140 located on manifold body 80, as illustrated in
Another embodiment of manifold 70 is illustrated in
Referring generally to
Depending on the specifics of a given use, the shape, size, and features of subsea landing string system 54 as well as the overall subsea system 30 may be adjusted. For example, different numbers of manifolds 70 and different numbers of hydraulic control lines 66 may be used in a given system according to the parameters of the hydrocarbon production operation or other subsea operation. Additionally, the types of manifold attachment mechanisms, manifold electronic modules, SEMs, valves, sensors, and other components may be selected according to the operational parameters. Furthermore, different numbers of solenoids and corresponding directional control valves may be used in each manifold and the flow circuitry for controlling flow to selected hydraulic control lines 66 may have various configurations.
Similarly, the flow paths for hydraulic actuating fluid 62 may be formed by various bores, pipes, conduits, and other flow channels coupled by various hydraulic connection mechanisms. Examples of such hydraulic connection mechanisms include seal stab connectors or JIC (Joint Industry Council) connectors having seals, e.g. O-rings, made from suitable materials. The hydraulic connection mechanisms also may comprise metal-to-metal seals or combination seals combining elastomers and metals.
Additionally, the modularity of the system enables mounting of manifolds 70 in other locations. For example, manifolds may be mounted on both the subsea landing string system 54 and on other components of the overall landing string. Similarly, the subsea landing string system 54 may be updated by adding and/or removing certain manifolds to accommodate production changes, operational changes, and/or different subsequent uses of the system. Individual manifolds 70 may have different configurations relative to other manifolds 70 used in cooperation with the subsea landing string system 54. Additionally, various types of seals and seal chambers may be employed to ensure continued protection of the electrical wires or other solenoid control lines while the manifolds 70 are exposed to environmental fluids such as seawater.
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.
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