INTEGRATED WELL SYSTEM ASSET AND HIGH INTEGRITY PRESSURE PROTECTION

A technique facilitates integration of a well system asset, e.g. a subsea asset, with a pressure protection system (PPS) to prevent over-pressurization on a downstream side of the well system asset. The PPS comprises a barrier structure which may be automatically actuated upon sensing the over-pressurization to block further flow through the well system asset. By combining the PPS and the 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.

BACKGROUND

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.

SUMMARY

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.

DETAILED DESCRIPTION

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 toFIG. 1, an example of a well system20for use in a well operation is illustrated. The well system20may have a variety of components and configurations in both surface applications and subsea applications. For example, the well system20may comprise a variety of well system assets22which are positioned to control flow of fluids, e.g. production of well fluids and/or delivery of injection fluids.

In a subsea application, the well system assets22may comprise many types of assets such as Christmas trees24mounted on wellheads26positioned over wellbores28. The well system assets22also may comprise manifolds30or various combinations of pipeline end manifolds or pipeline end terminations32. The various Christmas trees24, manifolds30, pipeline end terminations32, and/or other well system components may be connected in fluid communication via flowlines34. The flowlines34may include jumpers36located between and coupling certain well system assets22.

It should be noted, however, many types of additional and/or other well system assets22may be utilized in well system20to provide an overall well system network38. In the embodiment illustrated, the well system network38is a subsea network located at or proximate a seabed40. In this type of subsea application, the flowlines34may be routed along risers42, e.g. flexible risers, to a surface facility44located at a sea surface46. The surface facility44may comprise a surface vessel, platform, or other suitable type of surface facility. The flowlines34also may be routed to a land facility.

The overall well system20utilizes at least one integrated structure48, e.g. a plurality of integrated structures48, comprising a desired well system asset22combined with a PPS50, e.g. a HIPPS. For example, the illustrated subsea network38comprises integrated structures48in the form of integrated Christmas trees24and PPS50. However, the integrated structures48may comprise other types of well system assets22integrated with PPS50, as explained in greater detail below.

Referring generally toFIG. 2, an example of one type of integrated structure48is illustrated. In this embodiment, the PPS50is configured as a HIPPS integrated within a Christmas tree24which may be a subsea Christmas tree or a surface Christmas tree. By way of specific example, the Christmas tree24is in the form of a vertical Christmas tree having a vertical tree section52which may comprise a valve or a plurality of valves54. By way of example, the valves54may comprise a lower or master valve56and a top valve58, e.g. a swab valve.

In the example illustrated, the PPS50and the vertical Christmas tree24may share certain components. For example, the vertical Christmas tree24may comprise a wing60having a plurality of valves62which serves as a barrier structure64, e.g. a dual valve barrier structure for the tree. Depending on the application, the valve56also may be considered part of the barrier structure/envelope64. The barrier structure64can also function as part of the PPS50and may be automatically actuated to close off flow to downstream components upon the occurrence of an over-pressurization. A plurality of sensors66, e.g. pressure sensors, may be used to monitor pressures along a flow path67through the integrated structure48. In the illustrated example, the flow path67may comprise a production flow path disposed from valve56through valves62.

By way of example, the sensors66may comprise at least one upstream pressure sensor68located upstream of the barrier64, at least one downstream pressure sensor70located downstream of the barrier structure64, and at least one intermediate pressure sensor72located within the barrier structure64. In the example illustrated, a plurality of intermediate pressure sensors72, e.g. two intermediate pressure sensors72, may be located between the valves62of the barrier structure64. Additional sensors66, e.g. pressure sensors, also may be located along the flow path67extending between a fluid inlet74and a fluid exit76of the integrated structure48. In the embodiment illustrated, five pressure sensors66are illustrated as located along the fluid flow path67between the fluid inlet74and the fluid outlet76, however other numbers and/or types of sensors66may be employed according to the parameters of a given well application.

In embodiments wherein the well system asset22comprises a vertical Christmas tree24, the fluid inlet74may be positioned proximate to the wellhead26, and the fluid exit76may be located at a connector hub78. The connector hub78provides a coupling mechanism by which the integrated structure48is coupled with its corresponding flowline34, e.g. jumper36, and thus with other downstream components of the well system network38. As illustrated, the integrated structure48also may comprise a pressure regulator80which may be used to regulate pressure along the flow path67between the fluid inlet74and the fluid exit76. By way of example, the pressure regulator80may 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 hub78.

The integrated structure48might be coupled with or comprise a control system82. In subsea applications, the control system82may be in the form of a subsea controller which is assembled as part of the integrated structure48. By way of example, the control system82may comprise a Christmas tree control module84and a PPS control system86. The PPS control system86receives data from at least some of the sensors66. In response to the sensor data, the PPS control system86is able to provide control signals for selectively closing the barrier envelope by actuating the fluid barrier structure64to automatically close off flow through the integrated structure48upon sensing over-pressurization. Sensing the over-pressurization may comprise utilizing sensor(s)66to detect a pressure above a predetermined pressure threshold at a location or locations downstream of the regulator80. The Christmas tree control module84and the PPS control system86may 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 module84may be configured and/or programmed to incorporate the functionality of the PPS control system86.

The Christmas tree control module84and the PPS control system86of the control system82may be coupled with the appropriate components, e.g. corresponding sensors66, valves54,62, and barrier structure64, via suitable communication lines88. Depending on the application, the communication lines88may comprise electric lines, hydraulic lines, fiber-optic lines, umbilicals or other suitable communication lines88. For example, signals from sensors66may be provided to control system82via electrical or fiber-optic lines88. The valves54,62may be actuated via hydraulic control signals using hydraulic communication lines88. However, the valves54,62and/or other components may be electrically actuated or electro-hydraulically actuated. Accordingly, the communication lines88are 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 system82may be coupled with a surface control system90via a suitable telemetry system92.

Referring generally toFIG. 3, another embodiment of an integrated structure48of the disclosure is illustrated. In this example, the PPS50is again integrated within the Christmas tree24but the Christmas tree24is in the form of a horizontal Christmas tree in which the controllable valves54,62are located in a horizontal section of the Christmas tree24, e.g. the wing60. The vertical tree section52is generally provided to enable access into wellhead26and the corresponding wellbore28. Access through the vertical section52may be selectively blocked via a plug or other barrier94.

In this embodiment, many of the components are similar or the same as components described in the embodiment illustrated inFIG. 2and have been labeled with common reference numerals. As with the embodiment described in reference toFIG. 2, the PPS50and the horizontal Christmas tree24may share certain components. For example, the valve54and the valves62disposed in the horizontal wing60of the horizontal Christmas tree24may serve as the barrier structure64which also functions as part of the PPS50. In some embodiments, the barrier structure64may be in the form of a dual barrier structure, e.g. two valves62, but additional valves or other barrier elements also may be employed to form the overall barrier structure64. The barrier structure64may be automatically actuated to close off flow to downstream components upon the occurrence of an over-pressurization. The sensors66might be located along a flow path through integrated structure48to monitor a desired parameter or parameters, e.g. pressure.

As illustrated, the sensors66may comprise at least one upstream pressure sensor68located upstream of the barrier envelope/structure64, at least one downstream pressure sensor70located downstream of the barrier envelope/structure64, and at least one intermediate pressure sensor72located between the valves62of the barrier envelope/structure64. Additional sensors66, e.g. pressure sensors, may be located along the flow path extending between the fluid inlet74and the fluid exit76of the integrated structure48illustrated inFIG. 3. For example, other numbers and/or types of sensors66may be employed according to the parameters of a given well application.

When the well system asset22is in the form of a horizontal Christmas tree24, the fluid inlet74may be positioned proximate to the wellhead26, and the fluid exit76may be located at the connector hub78. This type of integrated structure48may also comprise a pressure regulator80for use in regulating pressure along the flow path67between the fluid inlet74and the fluid exit76.

The integrated structure48illustrated inFIG. 3might be coupled with or might comprise the control system82. The control system82may include control module84and PPS control system86as separate or integrated systems as described above. In this embodiment, the control system82/PPS control system86may again be configured to monitor sensor66and to output signals for automatically closing off flow at the barrier structure64upon sensing over-pressurization. Sensing the over-pressurization may comprise sensing a pressure above a predetermined pressure threshold via sensors66at a location or locations downstream of the regulator80.

Referring generally toFIG. 4, another embodiment of integrated structure48is illustrated. In this example, the PPS50is integrated within manifold30. The manifold30may be constructed in a wide variety of sizes and flow configurations with various types of manifold components known in the art to facilitate a desired flow pattern between components of network38, e.g. a surface or subsea network. As with embodiments described above, the PPS50and the manifold30may share certain components.

By way of example, the manifold30may comprise a plurality of connector hubs78coupled to flow lines34, e.g. jumpers36or other flow lines. For example, the connector hubs78may be used to couple the manifold with Christmas trees24, pipeline end terminations32, and/or a variety of other well assets22. The manifold30may also comprise a fluid flow network96arranged according to a desired pattern to enable flow between desired connector hubs78and thus between desired well assets22.

The manifold30also may comprise a plurality of manifold valves98disposed along flow passages of the flow network96to enable selective opening and closing of specific flow paths along the flow network96. In some applications, additional manifold valves98may be added to form a barrier structure64utilized by PPS50. The barrier structure64may comprise a multi-valve barrier structure, e.g. a two or three valve barrier structure, which functions as part of the PPS50and may be automatically actuated to close off flow to downstream components upon the occurrence of an over-pressurization. In the specific example illustrated, valves98are arranged to form a plurality of barrier structures64, e.g. two barrier structures, disposed along separate flow channels of the flow network96.

Sensors66may be located along flow paths of the manifold fluid flow network96to monitor a desired parameter or parameters, e.g. pressure. As illustrated, the sensors66work in cooperation with each barrier structure64and may comprise at least one upstream pressure sensor68located upstream of each barrier structure64, at least one downstream pressure sensor70located downstream of each barrier structure64, and at least one intermediate pressure sensor72located between the manifold valves98of each barrier structure64. Additional sensors66, e.g. pressure sensors, may be located at desired locations along the flow network96to monitor pressure or other desired parameters.

When the integrated asset22is in the form of manifold30, the integrated structure48may be coupled with or comprise the control system82. As with other embodiments, the control system82may comprise separate control systems or integrated control systems for controlling the functionality of the manifold30and the PPS50. In this embodiment, the PPS control system86may be configured to selectively and automatically close off flow at each barrier structure64upon 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 network96of manifold30.

Referring generally toFIG. 5, another embodiment of integrated structure48is illustrated. In this example, the PPS50, e.g. HIPPS, is integrated within a pipeline end manifold (PLEM) or pipeline end termination (PLET)32. The PLEM/PLET32may be constructed in a wide variety of sizes and with various internal components to facilitate cooperation with a corresponding well system asset22, e.g. a subsea manifold30. As with embodiments described above, the PPS50and the PLEM/PLET32may share certain components.

By way of example, PLEM/PLET32may comprise connector hubs78which may be coupled to corresponding flow lines34. The flow lines34may be coupled, in turn, to a corresponding manifold30or other well system asset22. The PLEM/PLET32comprises an internal flowline100arranged to enable flow between, for example, desired connector hubs78and a corresponding host asset.

In embodiments, the integrated structure48may incorporate an additional flowline valve or valves102compared to the single flowline valve102that may be used in a non-integrated PLEM/PLET. The additional valves102enable formation of the barrier structure64utilized by PPS50. As with other embodiments described herein, the barrier structure64functions as part of the PPS50and 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 valves102are arranged along flowline100to form the barrier structure64which automatically protects components downhole of the PLEM/PLET32from pressures above a predetermined threshold.

Sensors66may be located along internal flowline100to monitor a desired parameter or parameters, e.g. pressure. As illustrated, the sensors66work in cooperation with barrier structure64and may comprise at least one upstream pressure sensor68located upstream of barrier structure64, at least one downstream pressure sensor70located downstream of barrier structure64, and at least one intermediate pressure sensor72located between the flowline valves102of the barrier structure64. Additional sensors66, e.g. pressure sensors, may be located at desired locations within the PLEM/PLET32to monitor pressure or other desired parameters.

A control system82, e.g. a processor-based control system, may be combined with or provided as part of the integrated structure48. By way of example, the control system82may comprise the PPS control system86. The control system82/PPS control system86may be configured to automatically close off flow at barrier structure64upon sensing over-pressurization, e.g. sensing a pressure above a predetermined pressure threshold at a selected location or locations along flowline100of PLEM/PLET32.

The integrated structure48may be used in many types of surface well systems and subsea well systems. For example, the integrated structure or structures48may 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 structures48may 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 structures48may 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 structures48, 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 structures48enables lowering a single integrated structure48to 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 structure48may vary. For example, the barrier structure64may comprise valves or other types of controllable barrier elements. Depending on the application, the barrier structure64may 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 system82. Control system82may comprise various arrangements of well asset control module84and PPS control system86. Additionally, the arrangement of valves, internal flowlines, and other components utilized in each integrated structure48may 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 system82may be selected according to the parameters of a given surface or subsea well application.