TECHNICAL FIELD OF THE INVENTION

The present invention relates to a field configuration or layout of a pipeline system comprising an infield flowline and an export pipeline in connection with an inline manifold designed for serving a number of decentralized offshore producers of fluid at surface or at seabed, in particular intended for subsea distribution of hydrogen or a mixture with hydrogen and other fluid or for the purpose of injection, in the following commonly referred to as production fluid. The present invention is intended for distribution of production fluid from a number of decentralized offshore producers typically in the context of wind power plants, solar power plants, or wave/tidewater power plants, hydrocarbon wells, injection wells etc. By the term fluid in this application should be understood fluid in the form of gas and/or liquid.

BACKGROUND AND PRIOR ART

In this context, related prior art can be found in, e.g., W02020/095012 A1 disclosing an offshore wind turbine system for the large-scale production of hydrogen, or in W02020/157509 A1 disclosing apparatus, system and method for oil and gas operations subsea.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide a flexible and independent subsea fluid distribution system, allowing fluid production and distribution to start up at any stage in the field development.

It is another object of the present invention to provide a flexible and independent hydrogen distribution system allowing hydrogen production and distribution to start up at any stage in the development of an offshore wind power farm, an offshore solar power farm, or a wave/tidewater power farm.

These objects will be met by a subsea distribution system comprising: a number of producers arranged at surface or at seabed in decentralized positions relative to a subsea inline manifold; a jumper/riser connecting each producer with the subsea inline manifold; the subsea inline manifold comprising a manifold module and an inline Tee, the manifold module having a branch connection for each jumper/riser, the branch connections in flow connection with an infield flowline via a vertical up-facing hub integrated in the inline Tee; and the infield flowline connecting the subsea inline manifold to a pipeline end manifold or an export pipeline.

The manifold module comprises: a compiler fitting formed with a vertical bore leading from an integrated or assembled down-facing connection to each branch connection, a manifold branch valve integrated with each branch connection, and wherein the down-facing connection is arranged for connection to the up-facing hub of the inline Tee.

In one embodiment the manifold module comprises a lifting interface to allow a manifold lifting tool to be fixed to the manifold module for guiding, installation and retrieval.

In another embodiment the inline Tee has an isolation valve integrated in the vertical up-facing hub in order to avoid flooding of the infield flowline while connecting or disconnecting the manifold module.

The inline Tee may be designed with a rigid inline Tee header prepared with a flowline interface, such as a flange or other type of connection, at one or at each end, allowing a flexible infield flowline or export pipeline to be connected. The inline header can be realized as a pipe length with an upwards facing branch pipe, or the inline Tee can be provided as a block element with integrated header and branch pipe, the flange(s) or other type of connection(s) arranged at one or each end of the inline Tee block.

The inline Tee may be equipped with retractable guideposts to guide the manifold module during landing and retrieval. The inline Tee can be installed with or without the manifold module when laying out the infield flowline.

The inline manifold is adapted for use in any subsea production of hydrogen or a mixture with hydrogen and other fluid, or subsea production of hydrocarbon, as well as being useful for the purpose of CO2, water or service injection.

A subsea boosting unit may be connected to the export pipeline via inline Tees and upstream and downstream of a cross-over valve allowing hydrogen or other fluid flow to be routed via the boosting unit.

The subsea boosting unit may be arranged onto a fixed or floating unit at surface, and wherein a connection system allows fluid flow to be routed to surface via risers.

The invention is driven to achieve a flexible and independent system, allowing the fluid production and distribution to start up at any stage in the field development, in contrast to a daisy chain type solution where the producers must be installed in a fixed sequence or fully completed before the production can start. The only installation needed before start of fluid export is minimum one fluid producer 1, the infield flowline 4 with the inline-Tee’s, 9, and the manifold module 8 connected for the relevant producer.

The infield flowline 4, typical 8” to 16” diameter bore to be connected to inline Tee’s 9 that are configured with a vertical inlet 17 of typical 5” to 7” diameter bore with a manual isolation valve 15 with an integrated up-facing hub 16. The inline Tee 9 header 36 can either be welded or flanged to the infield flowline 4 via the flowline interface 35. A manifold module 8 with a compiler fitting 13 with two or more branch connections 12 is arranged to be landed vertically on the inline Tee 9 up-facing hub 16 and secured by a clamp, collet, or similar type of down-facing connection 14.

Each branch on the manifold module 8 is equipped with a manifold branch valve 11 typically 2” to 4” diameter bore. The compiler fitting 13 will be drilled with a vertical bore from the down-facing connection 14 and out to each of the branch connections 12 through the manifold branch valve 11. The manifold 8 can be installed together with the inline Tee 9 or separately. If the manifold module 8 is not installed a subsea cap can be installed on the Inline Tee 9 up-facing hub 16. The inline Tee 9 isolation valve 15 is arranged to be manually operated, such as by means of ROV or divers. The isolation valve 15 may alternatively be remotely operated, such as electrically or hydraulically operated from topside or onshore. The isolation valve 15 to be opened after the manifold module 8 is installed and secured in order to avoid the infield flowline 4 to be flooded with seawater, or in order to avoid hydrogen or hydrogen mixture with other fluid to leak out in case production is ongoing at other locations in the field. A lifting tool 41 is used to retrieve and install the manifold module 8. Guide sleeves 39 on the lifting tool 41 are arranged to ensure guiding towards the inline Tee 9. The Inline Tee 9 has a couple of retractable guideposts 43 for guiding of the manifold module. The retractable guideposts 43 are extended by tension from guide wires 37 anchored to the guidewire anchor receptacle 34 on the top of the retractable guideposts 43. Guide wire 37 can be used to guide the manifold module 8 or be removed after extending the retractable guideposts 43 if guide wires are not required.

A typical 2” to 4” diameter bore jumper/riser 2 is arranged to be connected between the hydrogen producer 1 and the inline manifold 3, the subject connections can typical be stab connections 33 operated by a subsea remotely operated vehicle. The jumper/riser 2 can be of riser type if the associated producer sits on a floating unit, or can be pulled through a J-tube in case the producer sits on a jack-up type foundation. A dry mate manual type connection can be used at the producer end of the jumper/riser in a surface configuration.

The invention allows for a more optimized and standardized pipe sizing as compared to a daisy chain solution, as the jumper/riser 2 reaches from each producer. Any start-up, maintenance, shutdown or removal of a fluid producer 1 will not affect the remaining production from other fluid producers 1 in the field as it can be isolated at the manifold module 8. Connecting the infield flowlines 4 into an export pipeline end manifold 5 also allows flexibility to start up production when installing only one infield flowline 4, and implement additional producers afterwards. The system is optimized to reduce the need for large flowline connections. The only flowline connections are between the infield flowline 4 and pipeline end manifold 5. The large export pipeline 6, typical 28” to 42” diameter bore out from the pipeline end manifold 5 can be welded/connected at surface and installed as one unit and will also avoid any additional pipeline end termination and spool. The pipeline end manifold 5 can be designed as a sledge to take any possible temperature and/or pressure expansions.

The export pipeline 6 can be installed dry as there are valves 22 on each of the pipeline end manifold 5 branches. If required, a de-watering pig can be pre-installed inside the pipeline end manifold 5, pushing water back to shore or another subsea application if the export pipeline 6 requires to be flooded during installation. A retrievable pig launcher can also be installed for de-watering, but this will require an end connection and a valve on the export pipeline 6 end matching the export pipeline 6 size. De-watering of the infield flowlines 4 can be done by pre-installing a de-watering pig at the back end of the outermost inline manifold 3 and then run the pig towards the pipeline end manifold 5. An integrated pig stop can be installed at the pipeline end manifold 5 branch, preventing the pig from entering into the pipeline end manifold 5 inboard pipe. The pig can then be returned back to starting point and be secured by a manual operated pig stopper. An alternative can be to use a retrievable pig launcher at outermost inline manifold 3 with the impact of adding a connection system and an isolation valve matching the infield flowline 4 size.

All lines in the system such as jumper/riser 2, infield flowlines 4, and export pipeline 6 can be either flexible or rigid. Layout presented indicates flexible riser 2 and infield flowline 4, export pipeline 6 is shown as rigid.

A boosting station can be added in case of long-distance export line or if higher pressure is required for other reasons. The boosting station can either be added to the pipeline end manifold 5 or be included as a surface or subsea standalone boosting unit 25 in fluid connection with the export pipeline 6 downstream the pipeline end manifold 5. An inline Tee 27 upstream export line bypass or cross-over valve 26 and an inline Tee 30 downstream export line bypass or cross-over valve 26 allow the flow to be routed via the boosting unit 25 when closing the cross-over valve 26. The Isolation valves 29 to be closed when removing the boosting unit 25 or when not in service. Connection system 28 allow boosting station to be connected or disconnected. The connection 28 can be connected to a riser if the boosting station is located on a jack-up, floating unit or similar. This solution also allows the boosting station to be included at any time without disturbing the production of hydrogen or a mixture of hydrogen with other fluid.

Further embodiments and advantages provided by the invention will appear from subordinate claims and from the detailed description below.

SHORT DESCRIPTION OF THE DRAWINGS

Fig. 1 is an isometric view of a Typical none scaled subsea fluid distribution field layout;

Fig. 2 is a partial top view of a Typical none scaled subsea fluid distribution field layout;

Fig. 3 is a partial isometric view of a none scaled decentralized fluid production with an inline manifold 3 collecting production fluid into an infield flowline 4;

Fig. 4 is an isometric view of jumpers/risers 2 and an inline manifold 3, connected to infield flowline 4;

Fig. 5 is an exploded view of an inline manifold 3 showing an inline Tee 9 with manifold module 8 and inline manifold protection cover 7;

Fig. 6 is an isometric view showing manifold module 8 being installed/retrieved onto/from the inline Tee 9, lifted by a lifting tool 41 and guided by guide wires 37;

Fig. 7 is an isometric view showing manifold module 8 landed onto the inline Tee 9, lifted by a lifting tool 41 ;

Fig. 8 is an isometric view showing manifold module 8 landed out onto the inline Tee 9, lifting tool 41 removed and guideposts 43 retracted;

Fig. 9 is an isometric view of a production fluid export pipeline end manifold 5 in service;

Fig. 10 is an isometric view of a production fluid export pipeline end manifold module 5; and

Fig. 11 is a schematic view of a Tee’ed off subsea or surface boosting station 25 connected to the export pipeline 6. DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION

Fig. 1 is an isometric representation of a field configuration of the present invention. A decentralized producer 1 , especially a hydrogen producer 1 or a producer of a mixture of hydrogen with other fluid, e.g., is shown as part of a windmill. A jumper/riser 2 from the producer 1 and down to an inline manifold 3. Infield flowlines 4 connecting the inline manifolds 3 to an export pipeline end manifold 5. An export pipeline 6 connected to the pipeline end manifold 5.

Fig. 2 is a top view representing parts of the present invention as described in figure 1. Decentralized fluid producer 1 shown as a dot at the end of the jumper/riser 2.

Fig. 3 is an isometric representation, representing one fluid production center of the present invention. The figure shows six of decentralized fluid producers 1 integrated into windmill, with a jumper/riser 2 between the producer 1 and the inline manifold 3 at the seabed floor. Infield flowlines 4 connected to the inline manifold 3.

Fig. 4 is an isometric view of the inline manifold 3, shown with the jumper/riser 2 from the producers and infield flowline 4 connected with a stab connection 33. This version shows the infield flowline 4 connected to the inline Tee header 36 via the flowline interface 35, in this case a flange type connection.

Fig. 5 is an exploded view of the inline manifold 3 consisting of an inline Tee 9 with manifold module 8 and inline manifold protection cover 7, the inline manifold protection cover 7 can serve a dual purpose as a fishing and dropped object protection as well as a means to collect leakage and detection by sensor if needed. The inline manifold protection cover can be used in organic fouling prevention. The manifold module 8 is shown as a compact compiler fitting 13 with integrated manifold branch valves 11, integrated stab connection 12 and a vertical down-facing connection 14 featuring hub and clamp for connection to inline Tee 9 with up-facing hub 16. The manifold module 8 is equipped with a lifting interface 19 at the center to allow connection with a manifold lifting tool 41 for subsea handling / installation and change out. The inline Tee 9 is equipped with an isolation valve 15 preventing infield flowline 4 to be flooded when connecting manifold module 8 or a cap. An integrated up-facing hub 16 is located on top of the isolation valve 15, allowing the manifold module 8 to connect with the inline Tee 9. An inline manifold mud mat 10 is shown connected to the inline Tee header 36 by clamp support 18 to provide bearing and torsion capacity and allow for the complete unit to slide on seabed. Retractable guideposts 43 are shown on each side of the up-facing hub 16 to allow guiding during manifold module 8 installation. The retractable guideposts 43 are guided by guidepost supports 32.

Fig. 6 shows the manifold module 8 being installed onto the inline Tee 9, by a lifting tool 41 connected to the manifold module 8 via the lifting interface 19. The lifting tool is equipped with a single pad eye 40 to interface with the lifting shackle 42 and have two of guide sleeves 39 to guide the manifold module 8 towards the up-facing hub 16 on the inline Tee 9.

Guide wires 37 with guidewire anchors 38 are installed into the guidewire anchor receptacle 34 on the retractable guideposts 43. The retractable guidepost 43 are extended when tensioning the guide wires 37.

Fig. 7 shows the manifold module 8 landed on the inline Tee 9 up-facing hub 16.

The down-facing connection 14 secures and seal the manifold module 8.

Fig. 8 shows the manifold module 8 landed on the inline Tee 9 up-facing hub 16.

The retractable guideposts 43 are in retracted position.

Fig. 9 shows an isometric view of export pipeline end manifold 5 in service, designed to connect the infield flowlines 4 to the export pipeline 6. The pipeline end manifold to be equipped with connections allowing the infield flowlines 4 to be connected. Pipeline end manifold 5 to be integrated with a mud mat 20 allowing for seabed support. A top cover 21 prevents for fishing gears, impact and allow for hydrogen sniffers to discover any leakage. The top cover 21 can be used in organic fouling prevention. Fig. 10 shows an isometric view of export pipeline end manifold 5, shown with four off branch connections 23. Isolation valves 22 on each branch avoiding export pipeline 6 to be flooded during connection of infield flowlines 4. All branches commingled into an appendix header 24 before vertical routed into the export pipeline 6. The export pipeline 6 is shown as a welded connection to the export pipe, planned to be welded at surface before installation. The blind end of the export pipeline 6 to be fitted with an anchor interface for either first or second end installation. A support structure 31 for the connection system shown as a structure directly connected to the piping. Mud mats 20 for seabed support directly connected to connection support structure 31.

Fig. 11 shows a subsea boosting unit 25 in context of production fluid export added to the export pipeline 6 downstream the pipeline end manifold 5. An inline Tee 27 upstream export line cross-over valve 26 and an inline Tee 30 downstream the export line cross-over valve 26 allow the fluid flow to be routed via the boosting unit 25 when closing the cross-over valve 26. The Isolation valves 29 to be closed when removing the boosting unit 25 or when not in service. Connection system 28 allow boosting station to be connected or disconnected. The cross-over valves 26 and connection system 28 can be at surface if the boosting station is located on a jack- up, floating unit or similar.

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