Patent Application
20180156004
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, the subsea system may comprise Christmas trees, manifolds, pipeline end terminations, pipeline end manifolds, and various other types of equipment which may be positioned at or proximate the seabed to contain and control the flow of produced well fluids and/or the delivery of injection fluids into the wellbore. Flow of fluids between the equipment is enabled via a network of tubular components, such as jumpers, pipelines, and other types of flowlines. In some operations, a separate high-integrity pressure protection system is coupled into the flow network to protect downstream components from high pressures. The high-integrity pressure protection system is deployed as a separate component with a separate controller to enable rapid shut off of the source of high pressure if a certain pressure threshold is exceeded.
In general, a system and methodology are described that enable the integration of a well system asset, e.g. a subsea asset, within a pressure protection system (PPS) to prevent over-pressurization on a downstream side of the well system asset. In embodiments, the pressure protection system might be a High Integrity Pressure Protection System (HIPPS) which is used herein to generally represent a safety instrumented system. The PPS comprises a fluid barrier structure which may be automatically actuated upon sensing an over-pressurization to block further flow through the well system asset. By combining the PPS and the subsea asset into an integrated structure, certain internal components and functionality may be shared. The integrated structure provides a substantially smaller footprint on, for example, the seabed while also providing a more cost efficient structure to construct and deploy.
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 enabling the integration of a well system asset, e.g. a subsea asset, with a PPS to prevent over-pressurization on a downstream side of the well system asset. The well system asset may comprise a Christmas tree or another type of asset, such as a manifold or a pipeline end termination. Additionally, the integrated well system asset and PPS, e.g. HIPPS, may be used in subsea applications or surface applications. The integrated structure provides an overall structure which may be deployed as a single structure on, for example, the seabed in a subsea application. The integrated structure enables greater space efficiency by avoiding spacing of the separate components in a well system layout. By integrating, for example, the functionality of the HIPPS and a subsea Christmas tree the seabed surface space utilized is substantially reduced by avoiding the open space which would otherwise be reserved around the Christmas tree. The simple construction and ease of deployment of the integrated structure, as opposed to two separate components, saves time, space, and/or cost.
The integrated structure utilizes a HIPPS having a fluid barrier envelope in the form of a fluid barrier structure which may be automatically actuated upon sensing the over-pressurization. In various embodiments, the barrier structure comprises a plurality of barrier elements, e.g. at least two barrier valves. The plurality of barrier elements may comprise, for example, a dual valve structure. Upon sensing a pressure in the well system asset higher than a predetermined pressure threshold, the HIPPS actuates the barrier structure to block further flow through the well system asset. By combining the HIPPS and the asset into an integrated structure, certain internal components and functionality may be shared. For example, the barrier structure utilized by the HIPPS may comprise valves found in the well system asset itself, e.g. the valves of the Christmas tree. The sharing of components provides the integrated structure with a smaller footprint compared to known Christmas tree and PPS juxtaposition on, for example, the seabed while also enabling a more cost efficient structure to construct and deploy.
Depending on the type of well system and well operation, the integrated structure may be used at a variety of positions within the overall well system. In general, the HIPPS portion of the integrated structure provides a safety function which monitors for over-pressurization which can damage well system components, e.g. downstream components. Based on signals received from monitoring sensors, e.g. pressure sensors, the HIPPS is able to shut off the source of the high-pressure so as to prevent rupture or other damage to downstream flowlines, downstream well assets, or other components that would be susceptible to damage if exposed to the over-pressurization.
By way of example, the integrated structure may be located between systems rated to handle different levels of pressure. If a subsea well is developed as a 10,000 psi system for a high-pressure reservoir but the existing subsea well system network is rated at 5,000 psi, for example, then a pressure regulating system may be needed to lower the high reservoir pressure to a desirable lower system pressure. In this type of application, an integrated structure according to embodiments of the disclosure may be used and may comprise an integrated Christmas tree and PPS to ensure that the higher reservoir pressure is not able to over-pressurize the lower pressure rated well system network located downstream of the integrated structure. In embodiments, the integrated structure monitors pressures upstream and downstream of the pressure regulator via pressure sensors at the Christmas tree. If pressure above a predetermined threshold is detected on the downstream side, the PPS portion of the integrated structure serves as a safety system to ensure shutdown and to prevent exposure of the downstream components to the over-pressurization.
Referring generally to
In a subsea application, the well system assets 22 may comprise many types of assets such as Christmas trees 24 mounted on wellheads 26 positioned over wellbores 28. The well system assets 22 also may comprise manifolds 30 or various combinations of pipeline end manifolds or pipeline end terminations 32. The various Christmas trees 24, manifolds 30, pipeline end terminations 32, and/or other well system components may be connected in fluid communication via flowlines 34. The flowlines 34 may include jumpers 36 located between and coupling certain well system assets 22.
It should be noted, however, many types of additional and/or other well system assets 22 may be utilized in well system 20 to provide an overall well system network 38. In the embodiment illustrated, the well system network 38 is a subsea network located at or proximate a seabed 40. In this type of subsea application, the flowlines 34 may be routed along risers 42, e.g. flexible risers, to a surface facility 44 located at a sea surface 46. The surface facility 44 may comprise a surface vessel, platform, or other suitable type of surface facility. The flowlines 34 also may be routed to a land facility.
The overall well system 20 utilizes at least one integrated structure 48, e.g. a plurality of integrated structures 48, comprising a desired well system asset 22 combined with a PPS 50, e.g. a HIPPS. For example, the illustrated subsea network 38 comprises integrated structures 48 in the form of integrated Christmas trees 24 and PPS 50. However, the integrated structures 48 may comprise other types of well system assets 22 integrated with PPS 50, as explained in greater detail below.
Referring generally to
In the example illustrated, the PPS 50 and the vertical Christmas tree 24 may share certain components. For example, the vertical Christmas tree 24 may comprise a wing 60 having a plurality of valves 62 which serves as a barrier structure 64, e.g. a dual valve barrier structure for the tree. Depending on the application, the valve 56 also may be considered part of the barrier structure/envelope 64. The barrier structure 64 can also function as part of the PPS 50 and may be automatically actuated to close off flow to downstream components upon the occurrence of an over-pressurization. A plurality of sensors 66, e.g. pressure sensors, may be used to monitor pressures along a flow path 67 through the integrated structure 48. In the illustrated example, the flow path 67 may comprise a production flow path disposed from valve 56 through valves 62.
By way of example, the sensors 66 may comprise at least one upstream pressure sensor 68 located upstream of the barrier 64, at least one downstream pressure sensor 70 located downstream of the barrier structure 64, and at least one intermediate pressure sensor 72 located within the barrier structure 64. In the example illustrated, a plurality of intermediate pressure sensors 72, e.g. two intermediate pressure sensors 72, may be located between the valves 62 of the barrier structure 64. Additional sensors 66, e.g. pressure sensors, also may be located along the flow path 67 extending between a fluid inlet 74 and a fluid exit 76 of the integrated structure 48. In the embodiment illustrated, five pressure sensors 66 are illustrated as located along the fluid flow path 67 between the fluid inlet 74 and the fluid outlet 76, however other numbers and/or types of sensors 66 may be employed according to the parameters of a given well application.
In embodiments wherein the well system asset 22 comprises a vertical Christmas tree 24, the fluid inlet 74 may be positioned proximate to the wellhead 26, and the fluid exit 76 may be located at a connector hub 78. The connector hub 78 provides a coupling mechanism by which the integrated structure 48 is coupled with its corresponding flowline 34, e.g. jumper 36, and thus with other downstream components of the well system network 38. As illustrated, the integrated structure 48 also may comprise a pressure regulator 80 which may be used to regulate pressure along the flow path 67 between the fluid inlet 74 and the fluid exit 76. By way of example, the pressure regulator 80 may be used to decrease a higher reservoir pressure to a lower pressure which falls within the pressure ratings of the system components downstream of the connector hub 78.
The integrated structure 48 might be coupled with or comprise a control system 82. In subsea applications, the control system 82 may be in the form of a subsea controller which is assembled as part of the integrated structure 48. By way of example, the control system 82 may comprise a Christmas tree control module 84 and a PPS control system 86. The PPS control system 86 receives data from at least some of the sensors 66. In response to the sensor data, the PPS control system 86 is able to provide control signals for selectively closing the barrier envelope by actuating the fluid barrier structure 64 to automatically close off flow through the integrated structure 48 upon sensing over-pressurization. Sensing the over-pressurization may comprise utilizing sensor(s) 66 to detect a pressure above a predetermined pressure threshold at a location or locations downstream of the regulator 80. The Christmas tree control module 84 and the PPS control system 86 may be independent control systems, e.g. independent processor based control systems, or they may be combined in an integrated system, e.g. a single processor based control system with dual functionality. In some embodiments, the Christmas tree control module 84 may be configured and/or programmed to incorporate the functionality of the PPS control system 86.
The Christmas tree control module 84 and the PPS control system 86 of the control system 82 may be coupled with the appropriate components, e.g. corresponding sensors 66, valves 54, 62, and barrier structure 64, via suitable communication lines 88. Depending on the application, the communication lines 88 may comprise electric lines, hydraulic lines, fiber-optic lines, umbilicals or other suitable communication lines 88. For example, signals from sensors 66 may be provided to control system 82 via electrical or fiber-optic lines 88. The valves 54, 62 may be actuated via hydraulic control signals using hydraulic communication lines 88. However, the valves 54, 62 and/or other components may be electrically actuated or electro-hydraulically actuated. Accordingly, the communication lines 88 are selected to carry the desired control and data signals, e.g. electrical, optical and/or hydraulic control signals. In a subsea application, the subsea control system 82 may be coupled with a surface control system 90 via a suitable telemetry system 92.
Referring generally to
In this embodiment, many of the components are similar or the same as components described in the embodiment illustrated in
As illustrated, the sensors 66 may comprise at least one upstream pressure sensor 68 located upstream of the barrier envelope/structure 64, at least one downstream pressure sensor 70 located downstream of the barrier envelope/structure 64, and at least one intermediate pressure sensor 72 located between the valves 62 of the barrier envelope/structure 64. Additional sensors 66, e.g. pressure sensors, may be located along the flow path extending between the fluid inlet 74 and the fluid exit 76 of the integrated structure 48 illustrated in
When the well system asset 22 is in the form of a horizontal Christmas tree 24, the fluid inlet 74 may be positioned proximate to the wellhead 26, and the fluid exit 76 may be located at the connector hub 78. This type of integrated structure 48 may also comprise a pressure regulator 80 for use in regulating pressure along the flow path 67 between the fluid inlet 74 and the fluid exit 76.
The integrated structure 48 illustrated in
Referring generally to
By way of example, the manifold 30 may comprise a plurality of connector hubs 78 coupled to flow lines 34, e.g. jumpers 36 or other flow lines. For example, the connector hubs 78 may be used to couple the manifold with Christmas trees 24, pipeline end terminations 32, and/or a variety of other well assets 22. The manifold 30 may also comprise a fluid flow network 96 arranged according to a desired pattern to enable flow between desired connector hubs 78 and thus between desired well assets 22.
The manifold 30 also may comprise a plurality of manifold valves 98 disposed along flow passages of the flow network 96 to enable selective opening and closing of specific flow paths along the flow network 96. In some applications, additional manifold valves 98 may be added to form a barrier structure 64 utilized by PPS 50. The barrier structure 64 may comprise a multi-valve barrier structure, e.g. a two or three valve barrier structure, which functions as part of the PPS 50 and may be automatically actuated to close off flow to downstream components upon the occurrence of an over-pressurization. In the specific example illustrated, valves 98 are arranged to form a plurality of barrier structures 64, e.g. two barrier structures, disposed along separate flow channels of the flow network 96.
Sensors 66 may be located along flow paths of the manifold fluid flow network 96 to monitor a desired parameter or parameters, e.g. pressure. As illustrated, the sensors 66 work in cooperation with each barrier structure 64 and may comprise at least one upstream pressure sensor 68 located upstream of each barrier structure 64, at least one downstream pressure sensor 70 located downstream of each barrier structure 64, and at least one intermediate pressure sensor 72 located between the manifold valves 98 of each barrier structure 64. Additional sensors 66, e.g. pressure sensors, may be located at desired locations along the flow network 96 to monitor pressure or other desired parameters.
When the integrated asset 22 is in the form of manifold 30, the integrated structure 48 may be coupled with or comprise the control system 82. As with other embodiments, the control system 82 may comprise separate control systems or integrated control systems for controlling the functionality of the manifold 30 and the PPS 50. In this embodiment, the PPS control system 86 may be configured to selectively and automatically close off flow at each barrier structure 64 upon sensing over-pressurization. Sensing the over-pressurization may comprise sensing a pressure above a predetermined pressure threshold at a selected location or locations within flow network 96 of manifold 30.
Referring generally to
By way of example, PLEM/PLET 32 may comprise connector hubs 78 which may be coupled to corresponding flow lines 34. The flow lines 34 may be coupled, in turn, to a corresponding manifold 30 or other well system asset 22. The PLEM/PLET 32 comprises an internal flowline 100 arranged to enable flow between, for example, desired connector hubs 78 and a corresponding host asset.
In embodiments, the integrated structure 48 may incorporate an additional flowline valve or valves 102 compared to the single flowline valve 102 that may be used in a non-integrated PLEM/PLET. The additional valves 102 enable formation of the barrier structure 64 utilized by PPS 50. As with other embodiments described herein, the barrier structure 64 functions as part of the PPS 50 and may be automatically actuated to close off flow to downstream components upon the occurrence of an over-pressurization. In the specific example illustrated, the flowline valves 102 are arranged along flowline 100 to form the barrier structure 64 which automatically protects components downhole of the PLEM/PLET 32 from pressures above a predetermined threshold.
Sensors 66 may be located along internal flowline 100 to monitor a desired parameter or parameters, e.g. pressure. As illustrated, the sensors 66 work in cooperation with barrier structure 64 and may comprise at least one upstream pressure sensor 68 located upstream of barrier structure 64, at least one downstream pressure sensor 70 located downstream of barrier structure 64, and at least one intermediate pressure sensor 72 located between the flowline valves 102 of the barrier structure 64. Additional sensors 66, e.g. pressure sensors, may be located at desired locations within the PLEM/PLET 32 to monitor pressure or other desired parameters.
A control system 82, e.g. a processor-based control system, may be combined with or provided as part of the integrated structure 48. By way of example, the control system 82 may comprise the PPS control system 86. The control system 82/PPS control system 86 may be configured to automatically close off flow at barrier structure 64 upon sensing over-pressurization, e.g. sensing a pressure above a predetermined pressure threshold at a selected location or locations along flowline 100 of PLEM/PLET 32.
The integrated structure 48 may be used in many types of surface well systems and subsea well systems. For example, the integrated structure or structures 48 may be used in subsea applications to protect downstream well system components having a lower pressure rating compared to the higher reservoir pressure, e.g. a 10,000 psi reservoir pressure versus a 5,000 psi well system pressure rating. In such a system, the integrated structures 48 may comprise integrated Christmas trees and PPS so as to protect components downstream of the well from the higher reservoir pressure. As described above, however, the integrated structures 48 may comprise various other well assets, e.g. subsea well assets, in combination with the PPS to protect against inadvertent over-pressurization of components downstream.
By using an integrated structure or structures 48, the number of components deployed to construct the overall well system is reduced. Additionally, the integrated systems reduce the amount of space utilized on, for example, the sea floor. In a conventional system, predetermined protective spaces, e.g. zones, are established around each subsea well asset. By integrating structures, the total number of such zones may be reduced. In subsea applications, the use of integrated structures 48 enables lowering a single integrated structure 48 to the sea floor rather than lowering a plurality of separate structures, thus simplifying deployment, installation and commissioning of subsea well assets, thus reducing costs of the operations.
Depending on the specifics of a given well application, the components of each integrated structure 48 may vary. For example, the barrier structure 64 may comprise valves or other types of controllable barrier elements. Depending on the application, the barrier structure 64 may comprise two or more barrier elements although some applications may utilize a single barrier element. The barrier valves and other barrier elements may be actuated hydraulically, electrically, or by other suitable actuation techniques under the control of control system 82. Control system 82 may comprise various arrangements of well asset control module 84 and PPS control system 86. Additionally, the arrangement of valves, internal flowlines, and other components utilized in each integrated structure 48 may vary depending on the desired construction of the corresponding well asset. Similarly, the number, type, and arrangement of sensors utilized in the integrated structure to provide data to control system 82 may be selected according to the parameters of a given surface or subsea well application.
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.
