JPS6257793B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is a marine flexible riser system for providing fluid communication between surface equipment and a subsea well head or manifold system. system and method for its installation.

An essential element in the recovery of fluid hydrocarbons from marine deposits is the establishment of a fluid communication system from the seabed to the surface after production capacity is established. Such systems, commonly referred to as production standpipes, usually include a number of conduits through which the various produced fluids are transported above the sea surface. Includes pipes for oil and gas products and lines or pipes for operational, electrical and hydraulic control.

For offshore oil and gas production, floating facilities may be used as production and/or storage platforms. This equipment is constantly exposed to sea surface and subsea conditions and is therefore subject to heaving, rolling, pitching and drifting. In order to function properly with such equipment, the production standpipe must be sufficiently flexible to compensate for such movements over long periods of operation without incident.

One example of such a marine standpipe is the flexible standpipe system described in US Pat. No. 4,182,594. This adaptable standpipe system is
It includes a vertical rigid section that extends from the sea floor to a fixed location at the bottom of the turbulent zone near the sea surface, and from the top of the rigid section that extends the turbulent zone. It includes a flexible section consisting of a flexible tube extending through it to a floating vessel on the surface of the sea. A submerged buoy is attached to the top of the rigid section,
Maintains the rigid portion in a substantially vertical position. In this type of standpipe system, there are often difficulties in installing and maintaining a flexible flow tube that is mounted on a rigid section such that the end section adjacent to it is not at the normal catenary departure angle. arise. This creates local stresses and causes undue wear on the terminal hardware within the flexible flow tube. If a natural catenary shape is adopted by the flow tube, the flow tube will approach the fixed part almost vertically in an upward direction at its point of suspension.

The object of the invention is to obtain a flexible standpipe system in which the flexible flow tubes assume a substantially vertical starting angle in their terminal portions.

According to the invention, a vertical conduit consisting of a number of flow tubes extending from the seabed to a submerged buoy section is used as a marine flexible standpipe system for connecting a subsea base to surface equipment. a yoke assembly mounted above the buoy section; and a number of deflectable catenaries disposed near one end in substantially perpendicular streamwise spaced relationship within the yoke assembly. a flexible conduit formed from the flow tube and a yoke assembly supported on the buoy section and operatively connecting the flow tube in the vertical conduit section to the flexible flow tube. A standpipe system is provided consisting of a number of rigid hanging conduits supported within a volume.

The invention also provides a method for installing such a marine flexible standpipe system in deep water, consisting of a number of flow tubes and terminating at the upper end with a submerged buoy section. A plurality of conduit sections formed from a plurality of conduits are attached to a subsea base in a substantially vertical position for connection to a source of hydrocarbon fluid, and a plurality of flexures are attached at one end to equipment above the sea surface. assembling a flexible conduit system including a flexible flow tube and a yoke assembly having the flexible flow tube supported therein in spaced relation at their other ends; attaching a yoke assembly to the buoy section with a flexible flow tube suspended from the yoke assembly at a substantially normal catenary departure angle; and attaching a number of rigid hanging neck conduits within the standpipe section. aligning the flow tubes supported within the flow tube and yoke assembly; and operatively coupling a hanging neck conduit to each flow tube for establishing fluid communication through the standpipe system. This method provides a method established from the following stages.

a rigid bow neck conduit serving to couple an upwardly directed flow tube in the vertical conduit section to the flexible flow tube; used in conjunction with a yoke assembly that maintains the end of the flow tube in a substantially vertical position and ensures that the flexible conduit follows a catenary path between the buoy section and surface equipment; Thereby, stresses in the flexible flow tubes and their associated end fittings can be greatly reduced, reducing system wear and extending service life and reliability.

The coupling between the hanger conduit and the vertical flexible flow tube is preferably a remotely controlled, eg hydraulically actuated, coupling. Preferably, each bow neck conduit includes at one end a hydraulically actuated coupling for coupling to a vertical flow tube and at the other end a coupling for coupling to a flexible conduit. Preferably, it includes a terminal portion for insertion.

The hang neck conduit is preferably supported on the buoy portion, preferably within a frame assembly that includes a trough for receiving and supporting the conduit. The conduit is suitably locked and held within the trough for more secure fixation.

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the following, a marine flexible standpipe system according to the invention will be described with reference to the accompanying drawings, which show embodiments thereof.

In the following description based on the drawings, certain parts of the flexible standpipe system are shown merely to explain one mode of operation. However, variations and modifications to these parts can often be made.
For example, offshore equipment need not be a production vessel. Because half-submersible units and floating platforms are
No. 4,098,333, a possible modification for use with a flexible standpipe. Similarly, the special construction of the subsea coupler may be adapted to a single well head, production system or manifold that collects and produces multiple wells to receive and process oil and gas. can.
Similarly, the submerged, free-standing lower standpipe section need not consist of rigid conduit. Because flexible piping or hoses tensioned by buoys are
3911688 and French Patent No. 2370219, it can be maintained in a fixed position when installed on the seabed. Also, while the lower standpipe is allowed limited movement, the upper flexible catenary section is relied upon to allow offshore equipment large horizontal movements and height changes.

First, refer to FIG. The figure shows a marine flexible standpipe system 20 in operation in an offshore location. This standpipe system 20
has a lower rigid part 21 and an upper flexible part 22. The lower rigid portion 21 is fixed to a base 24 above the seabed 23 and extends upwardly to a point just below a turbulent zone 25, which is located below the sea level, e.g. ,
An area under the sea that is normally influenced by surface conditions such as tidal currents, surface winds, and waves. The buoy section 26 containing the buoy chamber 31 is placed on top of the casing 27 of the rigid section 21 and is positioned to maintain this section 21 in a vertical position under tension.

As will be explained in more detail below, the deflectable section 22 includes a number of deflectable conduits 70 and expander beams 75, and the deflectable conduits 70 are rigid at the buoy section 26. is operatively connected to each flow passage within a certain section 21. The deflectable portion 22 extends downwardly from the buoy portion 26 via a catenary path before extending upwardly to the sea surface where it is connected by attachment means 71 to equipment 22a above the sea surface.

As shown in FIG. 1, the base section 24 and the lower portion of the rigid section 21 are typical marine standpipe components. The base 24 is located on the seabed 2.
3 and a submerged flow tube can also be connected to it. The pedestal 24 may be a multiwell connection template, a defined manifold center, or similar subsea structure. Each submerged flow tube terminates above a base 24 and is preferably fitted with a remote coupling, such as a "stub-in" coupling, at its lower end. As shown in FIGS. 1-6, the rigid part 21 is provided with a casing 27,
This has a coupler assembly (not shown) on its lower end, which itself engages a fitting on the base 24 to secure the casing 27 to the base 24. It may be made to match.

As shown in FIG. 2, a number of individual rigid flow tubes 30, which may be of the same or different diameters, are inserted into the casing 2 in a known manner.
7 through an internally or externally mounted guide. These flow tubes 30 are connected to the base 24
Attached via stub-in or threaded connectors to submerged flow pipes above the seabed 23
From the buoy part 2 at the top of the casing 27
Individual flow paths are provided up to a point adjacent to 6.

The buoy portion 26 has two buoy chambers 3 connected to diametrically opposite sides of the casing 27.
Contains 1. As shown in Figures 2 and 3, a beam 33 extends between and is attached to the buoy chambers 31 near their upper ends. The yoke receiving arm 34 is connected to the buoy chamber 31
attached to the outer edge of and extending horizontally outward therefrom.

Attached to the top of the casing 27 and secured to the beam 33 above the buoy section 26 are a number of holes for receiving and retaining an inverted U-shaped conduit (or hang-necked conduit), as described below. There is a support structure 35. Although for clarity only one such support structure 35 is shown in FIGS. It should be understood that a similar support structure 35 is included for conduit 30. The support structure 35 is
It can also include individual frames or frames designed in one piece. Although not shown, individual support structures 35 are individually placed at the bottom of each of the neck conduits 36, as shown assembled in FIG.

Please refer to FIG. Typical support structure 35
is fixed to the beam 33 of the buoy and the girder 39
It consists of a vertical frame 37 having a lower mounting element 38 secured along its upper surface. The trough 39 is sufficiently large to receive a corresponding helical neck conduit 36.

To increase the stability of the support structure 35,
Additional reserves may be provided for it.
To minimize scratches from wires or tools, for example, welding the steel plate between the support structures 35 at the grooves 39 and the open frame 37
By shaping the sides of the support structure 35
Preferably, the frame 37 is enclosed within a streamlined canopy. Support structure 35 for hanging neck conduit 36
Many variations can be made to . As shown in FIGS. 2, 3 and 4, the guide post 40
is attached to the buoy chamber 31 and extends upward therefrom. The functions of these guide posts 40 will be explained later.

Reference is now made to FIGS. 6 and 7. Hanging neck conduit 36 consists of a length of rigid tube 41 that is curved downwardly at each end to provide an inverted U-shaped flow path. A coupler 42 (e.g., a hydraulically actuated collet coupler) is attached to one end of the conduit 41;
It is also adapted to fluidly connect the conduits 41 to their respective rigid conduits 30 when the neck conduits 36 are lowered into the operative position. The extreme environmental conditions of subsea processing systems often cause equipment failure and repair problems, as well as pollution and product loss problems, but fail-safe valves are designed to minimize these problems. , usually,
Used for all flow tubes. Extra couplings and hydraulic actuators are desirable because of equipment accidents that often occur. Therefore, as shown in FIG. 6, an emergency sheath valve 43 is provided in conduit 41 directly above its male end. Preferably, valve 43 is of the fail-safe pressure release/spring closure type as is well known in the art (eg, a Grove ball valve having a Bettis actuator control 44). Preferably, the valves 43 do not act as the primary product shut-off means for their respective flow conduits (the primary shut-off means are typically located above the seabed 23, as is known in the art). ), it is only activated in emergency or maintenance operations to rewind the deflectable portion 22.

For each rigid conduit 30 there is an individually designed bow neck conduit 36. Attached to the horizontal portion of the upper surface of the neck conduit 36 by welding or other means is a partial sleeve 32 having one or more fitting necks 38 thereon. There is. As shown in FIG. 6, two pairs of self-latching clamps 46 are supported by sleeve 32. Each self-latching clamp 46 attaches to the support 32 on the sleeve 32.
A latch member 47 pivotally mounted on a
This member 47 has an engaging surface 47a on its lower end and a lug 47b on its upper end. Also, spring 48
However, the latch member 47 is always biased to the locked position. A hydraulic stubbing pot 49 is secured to the hang neck conduit 36 and a hydraulic line operates the hang neck conduit 36 from a stub-in valve (not shown) inside the pot 49 to the coupler 42. Extends to connect.

The running tool 50 has a guiding funnel 5 at each corner thereof.
2 (FIG. 8), the funnel 52 allows the running tool 50 to be lowered in proper alignment over the buoy portion 26 over the guide line. As shown, the guide pillar 40 above the buoy room 31
It is designed to cooperate with A hydraulically released overshot 53 is provided on the rack 51 for each fitting neck 38 on the sleeve 32. Hydraulic cylinders 54 are positioned on each side of overshot 53 with piston rods 55 adapted to engage latch ears 47b of latch member 47 such that piston rods 55 are removed from cylinders 54. When stretched, ear 4
7b to the unlocked position.

A main hydraulic coupling box 56 rests on top of frame 51 and from there connects hydraulic pipes (indicated by dashed lines in FIG. 6) to various hydraulic control mechanisms above frame 51. It's being postponed. Stub-in member 5
7 is supported by the frame 51, and
It is adapted to cooperate with pot 49 to establish a hydraulic fluid path to connector 42. A hydraulic test coupling box 58 is placed on top of the frame 51 and a hydraulic release tube 60 and a hydraulic release tube 60 extending therefrom to a collet test coupler 61 placed on the male end 45 of the hanging conduit 41. It has a pressure test tube 59. A tether 62 is connected between frame 51 and coupler 61. Attachment device 63
are provided to connect the frame 51 to a drill string 64 or other lowering device for lowering and raising the running tool 50. As shown in FIG. 8, in some cases more than one collar coupler assembly may be brought into position at the same time.

The flexible flow tube section 22 (shown in FIG. 1) is made up of a number of flexible catenary flow tubes 70, each tube connected to offshore equipment and its location above the buoy section 26. A respective helical conduit 36 is adapted to be operatively coupled thereto. The upper end of each flexible flow tube 70 is
1 to the floating facility 22a by any suitable means. The recommended flexible flow tube is Coflexip multi-layer coated conduit.
These conduits are circular conduits with a protective outer covering made of "Rilsan" material. Flow tubes are available in a variety of sizes and may be provided with removable ends. The bundle of ribbon flow tubes restrains the flexible flow tubes from mutual contact and provides sufficient clearance in the expander beam to allow unimpeded longitudinal movement. The flexible flow tubes 70 are arranged in a parallel alignment or "ribbon" substantially throughout their length.
held in a relationship. A plurality of flow tubes of equal length are spaced longitudinally along the flexible flow tube 70 to form a plurality of lateral spreader beams (four shown in FIG. 1). 75 (9th and 1st
(Fig. 0) can be maintained in parallel relationship.

The expander beam 75 is a crossbar 76 on which is placed a number of spaced guides 77, each guide adapted to loosely hold a respective deflectable flow tube 70. ing. Each guide 77 has a gate 78 that is hinged to allow each flow tube 70 to be placed into the guide 77 and then closed and pin 77a
and secure the flow tube 70 therein. Each guide 77 is large enough (eg, about 25% or more) to provide clearance around its respective flexible flow tube 70. To minimize scuffing of the flexible flow tube 70, the guide 77 may be lined with a plastic sleeve 79 having a low coefficient of friction.

Since the expander beam 75 is slidable relative to the flexible flow tube 70, a hanging support member is provided. A support rod or line 80 is connected to each beam 75 by clamping or attachment means 81 to maintain the beam 75 in a predetermined longitudinal position. The upper end of the support element 80 is connected to mounting means 71 on the floating surface equipment 22a, thereby allowing the expander beam 75 to be supported by the line 80.

A yoke assembly 82 (FIGS. 11 and 12) provides a means for connecting the deflectable section 22 to the buoy section 26. Yoke assembly 82 includes an elongated horizontal support member 83. This member 83 may be a box beam having a number of recesses 84 therein. Each recess 84 receives a corresponding flexible flow tube 70 in a linear row at horizontally spaced locations. A locking means, such as a gate 85 pivotally mounted in recess 84, secures the end of flow tube 70 to yoke 82. A hydraulic cylinder 86 laterally operates gate 85 between an open position (dashed line in Figure 11) and a closed, locked position. Hydraulic cylinder 86
may be permanently mounted on the yoke support 83 or may be removably mounted for installation by the diver when needed.

A hydraulically actuated linkage pin assembly 87 is attached to the opposite end of the support 83 and connects the horizontal yoke support 83 to the yoke arm 34 when the yoke assembly 82 is in position on the buoy section 26.
It is set to be locked. Yoke assembly 82
The yoke beam 8 is attached to the support arm 34 of the buoy part 26.
3 by a pair of hydraulically actuated connecting pin assemblies 87 located at the ends of 3. The retractable attachment member has an opposing retractable member 87c adapted to be retained within the slot 34a of the adjacent arm 34. The D-shaped bar profile and the engagement arrangement between the end of the yoke beam 83 and the support arm 34 allow the entire yoke assembly 82 to be lowered from the buoy section 26 and thereby This prevents angular strain and damage to the bundle of flexible flow tubes in the event of an accident or single retraction of the attachment means 87. A penstock 88 for operating various mechanisms on the yoke assembly 82 is attached to the yoke support 83.
is attached by a manual gate 89.

A main connection mounted on the end of each flexible flow tube 70 and adapted to remotely connect the flexible flow tube 70 to the male end 45 of the corresponding bow neck conduit 41. 90 (eg, a hydraulically operated Cameron collet coupler). An auxiliary or secondary fluid coupler 91 may be installed adjacent to the main coupler 90 to ensure the release of the deflectable flow tube 70 from the buoy portion 26 during an emergency situation. .

As shown in FIG. 13, located at the bottom of the secondary coupler 91 is a fitting 92 having a lip 93 thereon. A rotating metal plate 94 and a "Delrin" plastic plate 95 are rotatably and slidably mounted on the fitting 92, which also has a flexible flow tube 70 placed within the yoke 82. Until then, lean on the lips 93. A bearing plate 96 is secured to the coupling 92 and supports a jack consisting of three equally spaced, hydraulically actuated cylinders 98 that extend downwardly through the bearing plate 96. It has a piston 99 adapted to extend. The joint 92 connects the rotating metal plate 9 to the gate 85.
4, the metal plate 94 locks the alignment pin 100 (FIG. 14).

To install the flexible standpipe system 20 according to the invention, the lower rigid section 27
is mounted together with the buoy portion 26 on the base 24 in a predetermined position. A rigid conduit 30 is passed through the casing 27 and connected to a submerged flow tube on the base 24. US Patent No. 4182584
The number is the rigid part 27 and the rigid conduit 3.
2 shows a technique that can be used to install 0. Buoy chamber 31, beam 33, hanging neck support structure 35 and lateral yoke receiving arm 34
The buoy part 26 including the buoy part 26 can also be attached and installed in the casing 27 at the same time. Any protective caps or debris used during installation are removed from the top end of each rigid conduit 30 by a diver. The helical joint assembly is lowered over the running tool 50 into its respective trench 39 above the buoy section 26. A hanging conduit 36 is placed on the frame 51 of the tool 50;
As a result, the funnel 52 on the frame 51 becomes
After being lowered along the guide line attached to the guide post 40, the conduit 36 is properly aligned with its respective gutter 39 and rigid conduit 30 when engaging the guide post 40 above the chamber 31. to be done. When the bell neck conduit 36 is moved downwardly into the trough 39, the engagement surface 47a of the latch member 47
engages flange 39a (FIG. 7) on top of gutter 39 and moves member 47 outwardly until member 47 engages the lower portion of flange 39a. At the same time, the coupler 42 is moved over the upper end of the conduit 30 and
Means for actuating the coupler 42 is provided by a hydraulic connection via a pot 49 from above sea level.

After the coupler 42 is actuated, the collar conduit 36 and the coupler 42 allow the ball valve 43 to be opened either manually by the diver or via the penstock 43a (FIG. 6). , is then pressure tested by supplying water pressure via tube 59.
After the test is complete, test coupler 61 is released from male end 45 via tube 60. Connector 61
is connected to tool 50 via line 62 for removal together with tool 50. The fixing neck 38 on the sleeve 32 is released from the overshot 53 on the tool 50, and the tool 50 is
It is retracted for reuse in positioning additional crane necks 36. As shown in Figure 8,
More than one hanging neck 36 can also be installed in one operation.

If electrical and/or hydraulic power is required to operate a control device or instrument on the seabed 23, one or more control elements (e.g., 30a in FIG. ) is provided in the casing 27 and extends over the support frame 37 so that its upper end 41a (FIG. 12) terminates in approximately the same position as the bow neck conduit 36 terminates. It can also be done. When all bow neck conduits 36 are in the operative position above the buoy section 26, the upper deflectable section 22 is installed.

In one technique for assembling and installing flexible section 22, flexible flow tube 70 and electrical cable 70a (FIG. 12) are connected to a powered reel (not shown) on vessel 22a. stored on top of. One end of each flexible flow tube 70 and electrical cable 70a includes:
It is connected to a plug 101 that is lowered upside down through the moon pool A of the ship 22a. plug 101
can be passed between moonpool A and moonpool B by line 102. Alternatively, the moonpool plug or portion thereof can be pre-installed by individually threading and attaching the flexible wires. A support line 80 supporting the expander beam 75 can also be attached to the plug 101 and paid out with the flow tube 70. The expander beams 75 can be assembled on the flow tubes 70 or each flow tube 70 separately in its respective guide 77 on the beam 75 as each beam 75 enters the sea. It can also be placed by the diver after the dive. After plug 101 and/or flexible flow tube 70 is threaded toward moonpool B, yoke assembly 82 is inserted over the ends of flow tube 70 and electrical cable 70a.
It can be installed as shown in Figure D.

After the flexible portion 22 is assembled, the rotating plug 101 is pulled into the moonpool B of the vessel 22a and installed therein. yoke 82
is lowered by line 110 (FIGS. 12 and 19A-19D) to a position directly below yoke support arm 34 above buoy portion 26. Diver D leaves the diving bell 111 and attaches the support line 112 (FIG. 19D) to the guide line 113. By means of a winch (not shown) above the buoy portion 26 and the guy line 112, the diver D can guide the guide line 113 through the guide shuttle 1.
15 (FIGS. 11 and 12), these shoes 115 are split or hinged to allow guide wires 113 to enter. The slack above the guide wire 113 is then taken up and the yoke 82 is pulled into position above the yoke support arm 34. When the yoke 82 is pulled upward, the connecting pin assembly 8
7 (FIGS. 11 and 12), the upper support 87a is
Slot 34 on support arm 34 (Figures 2 and 4)
Pass through a. Hydraulic cylinder 87b is then actuated to move crossbar 87c into engagement between upper support arms 34, thereby causing yoke 82
is locked in place on the buoy portion 26.

Cylinder 98 (FIGS. 13-17) is then actuated to move coupler 90 into engagement with male end 45 of bellows conduit 36;
is actuated to ensure a connection between the collar conduit 36 and the flexible flow tube 70. Diver D then makes the electrical and hydraulic connections between cables 41a and 70a and completes the installation.

Alternatively, flow tube 70 can be assembled into yoke 82 after yoke 82 is placed in the sea. This procedure can also be used for initial installation or for separately replacing flexible flow tubes.

Next, reference is made to FIGS. 13-18. York 8
The gate 85 above 2 is moved to the open position (FIGS. 13 and 14) by a hydraulic cylinder 86.
The guide line 103 connects to the loading gate 85 and the gate 85
It is attached via a plug 104 extending through a hollow locating pin 100 on the lateral pin 1
05 (FIG. 18). Guide wire 103 cooperates with an opening in rotating plate 94 and provides guidance of flow tube 70 into gate 85 . The nipple 106 (FIG. 13) is the coupler 90.
The lower wire 107 is attached to the nipple 106.

A flow tube 70 is lowered over a gate 85 by a line 107 over a guide line 103;
5 supports the weight of the flexible flow tube 70 until the connection is made. An opening in rotating plate 94 engages and receives locating pin 100 on gate 85. Flow tube 70 is then lowered further until bearing plate 96 overlies "Delrin" plate 95. Thereafter, the cylinder 86 closes the gate 85 (FIGS. 15 and 16), and the locking pin 95a is inserted by the diver so that the gate 85 is closed and locked. Then, guide line 10
3 is removed from gate 85 and nipple 106
can be released from coupler 90 and taken back by line 107.

If a flow tube 70 requires repair or replacement, the tubes 70 can be individually disconnected from their respective neck conduits 36 and their gates 85 on the yoke 82 opened. can be replaced by. The descending line 107 is the coupler 9
Attached to return flow tube 70 to zero. The expander gates 77 are opened one after another,
Remove failed flow tube 70. In very deep waters, the use of divers is impractical. However, a large gap between the expander beam and the circular flexible flow tube may cause the flow tube and its terminal portion to be removed from one end of the flow tube bundle through the expander. Allow yourself to be drawn. A replacement flow tube 70 can be assembled into the flexible section 22 in a manner similar to the original installation procedure.

In case of an emergency situation, the deflectable section 22 can be quickly released from the buoy section 26. Each flow tube 70 is disconnected from its respective bow neck conduit 36 by releasing the main coupler 90 or, if coupler 90 has failed, by removing the second coupler 91. It can be released by releasing. The connecting horizontal bar 87c of the assembly 87 is retracted, and the yoke 82 is connected to the support arm 3.
To be freed from 4. Assembly 87 is such that if only one rod 87c is retracted and the other assembly 87 fails, yoke 82 will be released at the free end, thereby causing yoke 82 is designed to pull the failed rod 87c as it descends.

[Brief explanation of the drawing]

Fig. 1 is an overall schematic diagram of one embodiment of the present invention, Fig. 2 is a plan view of the buoy portion thereof, Fig. 3 is a side view of the buoy portion shown in Fig. 2, and Fig. 4 is a hanging neck. 5 is a plan view showing the buoy section of FIG. 3 with a hanging conduit yoke assembly and flexible flow tube attached; FIG. 6 is a plan view of the buoy section of FIG. FIG. 7 is a cross-sectional view taken along line 7-7 of FIG. 6; FIG. 8 is a cross-sectional view of the running tool guide for installing the hanging neck conduit; FIG. 9 is a side view of the flexible flow tube section containing the expander beam; FIG. 10 is a cross-sectional view of the flexible flow tube section containing the expander beam; FIG.
1 is a plan view of the yoke assembly, FIG. 12 is a side view of the yoke assembly, and FIGS. 13-17 show a portion of the yoke assembly as installed in the bow neck conduit of the flexible flow tube and its fittings. 18 is a side view of the guideline connection mechanism, and FIGS. 19A-19D are schematic diagrams showing the installation sequence for a flexible standpipe system. 20... Standpipe system; 21... Rigid part; 22... Flexible part; 24... Base;
26... Buoy part; 36... Hanging neck conduit; 39...
42... coupler; 70... flexible flow tube; 75... expander bar; 82... yoke assembly; 90... coupler.

Claims (1)

[Scope of Claims] 1. A marine flexible standpipe system for connecting a subsea base to surface equipment, consisting of a number of flow tubes extending from the sea bed to a submerged buoy section. a yoke assembly mounted on a vertical conduit section and a buoy section near one end of the yoke assembly; a flexible conduit section comprising a flexible catenary flow tube and a flexible flow tube supported on the buoy section and a flow tube in the vertical conduit section supported within a yoke assembly; A standpipe system comprising a plurality of rigid hanging conduits operatively connected in fluid communication with the standpipe system. 2. Each rigid hanging conduit has at one end a hydraulically actuated coupler operatively connecting the conduit to a flow tube in the vertical conduit section and at the other end a yoke assembly. a terminal portion operatively connected to a flexible flow tube supported within the
A standpipe system according to claim 1, each comprising a standpipe system according to claim 1. 3. The method of claim 1 or 2, wherein each crane neck conduit is supported above the buoy portion in a frame assembly including a trough for receiving and supporting the crane neck conduit. Standpipe system. 4. The standpipe system of claim 3, wherein the frame assembly also includes means for locking and retaining the hang neck conduit within the thorn. 5. A standpipe system as claimed in any one of claims 1 to 4, wherein each flexible flow tube depends from the yoke assembly at a substantially normal catenary departure angle. 6. In a method for installing a marine flexible standpipe system in deep sea, comprising a multi-conduit system consisting of a multiplicity of flow tubes in a substantially vertical position, on a buoy section whose upper end is submerged; attaching the terminating standpipe section to a subsea base for connection to a source of hydrocarbon fluid; and a flexure comprising a number of flexible flow tubes attached at one end to equipment above the sea surface. a yoke assembly in which the flow tubes are supported in spaced relationship adjacent their other ends; hanging from the yoke assembly at a substantially normal catenary departure angle; aligning the plurality of rigid bow neck conduits with flow tubes in the deflectable conduit section; connecting a pipe to establish fluid communication through a standpipe system.