JPH0241693B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention is used to verify the structural integrity of a subsea pipe prior to connecting the pipe end portion to a subsea connection point such as a well head on the sea bed. This invention relates to a test cap for an underwater pipeline that can be removably attached to and used in an end assembly of an underwater pipeline.

Conventional technology Undersea technology currently involves drilling oil wells and
To provide a stable place to complete and connect them, a mounting foundation attached to the seabed is used. Distributed well heads can accommodate existing production facilities such as offshore drilling platforms,
Alternatively, it can be connected to a floating production facility.
Similarly, supply oil line manifolds for combining multiple oil well lines for connection to ships at sea or the like, subsea lines for the handling and connection of multiple types of fluids. It is made so that you can use it. Often, bundles of pipes, including production lines, fluid control lines, and service lines, are connected between subsea connections. The conduit is a relatively rigid conduit that is pulled by a line between prefabricated and fixed locations on land or elsewhere between fixed subsea mounting foundations. It is stretched and transported. In some cases, long, flexible conduits are laid from a moving ship and wound onto the ocean floor. Conduits are constructed from high-grade materials and fittings and are typically tested for leaks at sea before being installed on the seabed.

However, no satisfactory method has yet been developed for testing the integrity of conduits in situ before they are laid and connected to connection points. This is because damage to pipelines that occurs during transportation and installation is difficult to detect without actually pressurizing the pipeline in situ at its final location; The coupling of is often an irreversible operation or
At the very least, this is an extremely expensive and difficult task to reverse.

SUMMARY OF THE INVENTION The present invention provides that the integrity and fluid handling capacity of a subsea pipeline be tested in situ on the seabed prior to its connection to a seabed connection point. The objective is to obtain a test cap for underwater pipelines that will enable this.

Means for Solving the Problem According to the invention, this problem is achieved by providing a subsea conduit consisting of a number of conduits between a rear block member having a flat inner surface and a flat inner surface of the rear block member. a front yoke plate adapted to bear directly on its inner mounting collar at its rear face for receiving a terminal assembly thereof, each opening into a flat inner surface of the rear block member; a number of cylinder chambers coaxially aligned with the conduit in an inward mounting collar of the conduit which is pressed directly against the front yoke plate; each cylinder chamber being mounted for axial movement within the cylinder chamber; In use, each cylinder chamber behind the piston assembly installed in each cylinder chamber communicates with a conduit in the inner mounting collar of the aligned conduit. and means for coupling the piston assembly with an inner mounting collar of the conduit to enable testing of the structural integrity of the conduit. This problem is solved by a test cap for underwater pipelines.

The means for ensuring that each cylinder chamber is pressurized is
Preferably, one or more fluid passages extend through the length of each piston assembly, allowing pressurized fluid from the conduit access to the cylinder chamber. This is desirable.

The front face of the piston assembly is suitably provided with an O-ring device to ensure that the piston assembly is leaktight around the end of the conduit therein against the face of the inner mounting collar. be able to do so. The O-ring is preferably spaced inwardly around the front periphery of the piston assembly, such that the rear area of the piston assembly is limited to the interior of the O-ring for pressurized fluid. than the front gives,
It is desirable to provide a larger area so that the piston assembly is forced toward the inner mounting collar.

It is advantageous if the piston assembly is also spring loaded towards the inner mounting collar;
Appropriately, one or many O
It is advantageous to have a ring which is leaktight against the inner circumferential surface of the cylinder chamber.

The test cap is a conduit consisting of a number of conduits.
lower it onto the inner mounting collar of the conduit;
This causes the yoke to press against the rear surface of the inner-mounted collar. Removal of the test cap is simply the reverse of this operation. however,
Advantageously, retention means are provided for the test cap in order to prevent accidental or premature removal or movement of the test cap from the inner mounting collar. This retaining means is most suitably in the form of one or more shear pins attached to the test cap, the shear pins being mounted on the conduit or the end assembly of the conduit. The shear pins can be engaged by a slit collar behind the inner mounting collar and the shear pins can be applied with a sufficiently large force to shear the shear pins and the test cap can be removed. Prevent relative lateral movement between the test cap and the slit collar until such time as possible.

For this purpose, the test cap is provided with a latch sleeve, by means of which it can only be lowered into position around the slit collar and lifted from this position. to shear the shear pins that hold the test cap in place.
It also allows a liberating force to be applied.

Embodiments Hereinafter, the present invention will be described in detail with reference to FIGS. 1 to 10 of the accompanying drawings showing embodiments thereof.

First, FIG. 1 shows the work to lower the underwater pipeline 10, and it is assumed that one work vessel 3a, 3b is used at each end of the underwater pipeline 10. (In FIG. 1, each end of this underwater pipeline 10 is to be connected to a well head 1, which is a first submarine connection point, and a second submarine connection point 2, respectively. ). During towing and installation of the subsea pipe 10, the subsea pipe 10 may be supported by spaced buoys 11. Cables 4a and 4b are attached to each end of the underwater pipeline 10, making the underwater pipeline 1 buoyant in this way.
0 to the well head 1 and the second connection point 2,
Each is pulled into place to connect. Although test caps 30 in accordance with the present invention are used at each end of the subsea pipeline 10 (and could be used at only one end), these test caps 30 may be used as described below. , which can be removably mounted on the terminal assembly of the subsea pipeline 10. Buoy 11 is underwater pipe 1
0 is placed between the well head 1 and the second connection point 2, it is released in a known manner.

A typical subsea pipeline 10 termination assembly used to connect to a test cap 30 and other fittings such as a well head 1 is shown in FIG. FIG. 2 is a front view of the underwater pipeline 10 with a portion cut away to show the passageway. Individual conduits 10, 12 of the subsea pipeline 10 (note that the same reference numeral 10 is used for convenience for one of the subsea pipeline systems and the conduits that make up it) is bolted to a mandrel 20 forming the terminal assembly. The mandrel 20 has an outer slit collar 22 and an annular inner mounting collar 24. The mandrel 20 also has a flat end surface portion oriented perpendicular to the longitudinal axis of the subsea conduit 10. Additionally, the mandrel 20 includes a number of fluid passageways 10a, 12a, respectively.
12 are longitudinally provided as continuous extensions of the conduits 10, 12, the inner diameter of which fluid passages 10a, 12a are parallel to the conduits 10, 12a to provide linear flow.
2, respectively, are coaxially aligned.
These fluid passageways 10a, 12a also connect test caps 3 to the terminal assembly, as explained below.
0 is also aligned with each corresponding piston assembly 50 of the test cap 30.

The inner attachment collar 24 of the mandrel 20 is
It is adapted to receive a C-shaped front yoke plate 34 forming part of the test cap 30, which front yoke plate 34 is mounted behind the inner mounting collar 24 in direct contact with its rear surface. It is designed to be inserted so as to make pressure contact. This relationship is illustrated in FIG. 3, which shows a side view of a test cap 30 attached to a mandrel 20 of a subsea pipeline 10. The test cap 30 consists of a yoke body including rectangular metal side plates 32 to which a front yoke plate 34 is attached, for example by bolts or welding. There is. The rear leak-proof plate or the rear block member 36 and the top plate 38 are securely attached to each other and to the metal side plates 32 and the metal yoke plate 34 in a similar manner to form the yoke body. ing. Hasp sleeve 39
may be welded to the top plate 38 to attach a pull wire to the test cap 30 during removal of the test cap 30. A pair of shear pins 35 attached to the front yoke plate 34 are placed diametrically opposite each other in slits formed in the outer slit collar 22 of the mandrel 20, thereby securing the test cap 30. is prevented from being moved transversely to its longitudinal axis prior to its removal from the mandrel 20.

The rear block member 36 of the test cap 30 is
The mandrel 20 has a flat inner surface adapted to be joined to the end surface of the mandrel 20, in which a number of cylinder chambers are drilled to the desired depth in its front part. It is adapted to receive a leaktight assembly in the form of a corresponding piston assembly 50 which is coaxially aligned with a corresponding fluid passageway 10a, 12a in the piston assembly. The rear block member 36 of the test cap 30 is shown partially cut away in FIG. 3, with a typical piston assembly 50 housed within the recessed cylinder chamber. , the piston assembly 50 is aligned with the corresponding fluid passageway 10a of the mandrel 20 and is used to block the fluid passageway 10a during testing of the subsea pipeline 10, i.e., during testing. In order to ensure that there are no leaks within the conduit 10,
It is used to block the

A typical shell-and-tube test cap apparatus is shown in FIG. 4, which shows test cap 30 in a front view. The front yoke plate 34 is
The test cap 30 has a C-shaped opening that allows the test cap 30 to be attached to the mounting collar 24 of the adapter 20 bolted to the terminal assembly of the subsea conduit 10 by vertically sliding the front yoke plate 34. It is designed to be placed on top of the . shear pin 3
5 is a pin attachment member 35 attached to the front yoke plate 34.
a to the front surface of the front yoke plate 34, and the shear pin 35 extends longitudinally from the front yoke plate 34 and is attached to the adapter 20. It is adapted to be retained by a slit in the outer slit collar 22, in which case the test cap 30
During the removal of the shear pin 35, forces transverse to its longitudinal axis are transmitted to the shear pin 35, causing its failure.

As shown in FIG. 4, the front yoke plate 34 and the top plate 38 are connected to each other and to the test caps by cap screws having recessed heads arranged in a linear row. 30 is attached to adjacent metal side plates 32 and a rear block member 36 forming the yoke body. The yoke body of the test cap 30 has the shape of an open bottom shell that is strong enough to withstand high pressure stresses. Rear block member 36 of the yoke body forming the test cap 30
has a number of recesses drilled at a certain depth from its rear face facing the outer slit collar 22, aligned with the fluid passages 10a, 12a provided in the mandrel 20, and in each recess. teeth,
A piston assembly 50, each forming a leaktight assembly, is slidably housed. These recesses may each include relatively large cylinder chambers 40, 41 and 42 that are aligned with production fluid pipes and service pipes. A set of small cylindrical chambers 43 may be used to receive a leak-tight assembly for a fluid line. These chambers 43 may be drilled to a predetermined depth, which depth is slightly greater than the axial dimension of their respective seal assembly or piston assembly 50. . Arrows 3-3' in FIG. 4 indicate the partial cut locations in FIG.

Piston assemblies 50 as leak-tight assemblies for typical conduits 10, 12 are included in the fifth and sixth pistons.
As shown in the figure. A cylindrical piston assembly 50 having a flat front surface 52 is provided with a set of guide holes 53 .
accommodates a set of shouldered retaining screws 54. These retaining screws 54 also hold the piston assembly 50 in place as a leaktight assembly, permitting axial movement, and keeping the surface 52 of the piston assembly 50 substantially flush with the inner surface of the rear block member 36. limited to a front position that is flush with the front.
A central passageway 56 in the piston assembly 50 provides fluid communication between the fluid passageway 10 a of the adjacent mandrel 20 and the cylinder chamber 40 behind the piston assembly 50 .
a and the cylinder chamber 40 is established. A spring device 60 longitudinally biases the piston assembly 50 toward the fluid passageway 10a so that the flat front surface 52 faces toward the end surface of the mandrel 20. Recessed annular groove 6 in front surface 52 of piston assembly 50
4 retains a first resilient O-ring 70, a portion of which projects outwardly from the front surface 52 of the piston assembly 50 toward the mandrel 20. ing. The difference between the relatively large net rear area receiving pressurized fluid in the longitudinal direction of piston assembly 50 and the smaller net area surrounded by O-ring 70 was determined during testing. The front and rear surfaces of the assembly 50 are provided with a fluid means for creating a pressure differential, which fluid means causes the O-ring seal 70 in the front surface 52 of the piston assembly 50 to be brought into contact with the opposing mandrel 20. The net force, which is the difference in the pressing force, pushes it toward the end surface of the

The outer peripheral surface of the piston assembly 50 and the cylinder chamber 4
1 piece to prevent leakage between the inner peripheral surface of
Alternatively, multiple O-ring seals 72 are arranged in respective concentric O-ring grooves.

In addition to large sized test units having larger piston assemblies 50 as shown in FIGS. 5 and 6, intermediate sized units as shown in FIGS. 7 and 8 and 9 and 10 A single guide and spring unit of smaller dimensions may also be used, as shown in the figures. These modification units are advantageous embodiments due to their small space requirements.

The intermediate size unit shown in FIGS. 7 and 8 is generally the same as the unit shown in FIGS. 5 and 6, but includes a cylinder chamber 42 containing a piston assembly 250. , the piston assembly 250 is secured to the biasing spring 2 by means of a retaining screw 254 housed in a guide hole 253.
It is held against 60. The piston assembly 250 also includes a central fluid passageway 256, a front surface 252 thereof, an O-ring seal 270 in the front surface 252, and an O-ring seal 272 on the outer circumferential surface. As can be seen from FIGS. 7 and 8, the central fluid passageway 256 receives a central column 280, the purpose of which will be explained below.

The unit shown in Figures 9 and 10 is again
It is generally similar to the unit shown in FIGS. 5 and 6, but because of its smaller dimensions,
A piston assembly 150 is retained in a central guide hole 153 in cylinder chamber 48 by a single retaining screw 154 housed around a single biasing spring 160. There is a difference. In this case, multiple fluid passages 156 are provided. As in larger size units and intermediate size units, the piston assembly 1
The front surface 152 of 50 has an O-ring leak stopper 17
0, and its outer peripheral surface includes a pair of O
Contains a ring stopper.

In the test cap described above, a rear access port (not shown) is drilled into the test chamber behind the piston assembly to which pressurized fluid may be communicated from an external source of pressurized fluid. I can do it. During testing of multiple service lines for through-flow line tools (TFL tools), connected approach ports allowing fluid communication between a pair of ports are used to ensure that fluid is in one test cap. Allow it to be pumped in through a tube and pumped out through another tube. Final marking of subsea conduit 10 is performed by pushing a TFL tool with a front marking force recording device toward the marking on the front surface of central column 280 (Figures 7 and 8). Before connection, clearance for the passage of the TFL tool can be ensured. After recording the imprint, the fluid flow is reversed to retract the TFL tool for reuse in other service tube tests.

Strength and corrosion resistance must be considered in the selection of materials for the construction of test cap 30 and related equipment. Steel, aluminum alloys, titanium and other high performance metals are recommended for the test cap yoke body, piston assembly and spring. Various elastomeric materials are used in O-ring seals, including silicone rubber and butyl rubber.

The test cap 30 described above has various modifications.
It can be done. For example, underwater piping 10
Rather than being contained in a compact structure, the tube may consist of a number of conduits arranged in a row of parallel conduits. Typically, the terminal assembly is a flat fitting perpendicular to the fluid conduit and the test cap is attached in direct mating relationship. However, geometric variations are possible while retaining the important functionality of the test cap and providing removable attachment of the device.

During leak-tight testing of subsea piping 10 under subsea conditions, a test cap 30 is installed over each end assembly of a length of typical semi-rigid subsea piping 10. Before the installation of such a subsea conduit 10 is lowered to the sea surface by a buoy 11, each fluid conduit 10, 12 is filled with an incompressible liquid. A pressure gauge is attached to the cylinder chamber 40 by screwing through the rear of one test cap 30. After pressurizing the individual fluid control conduits, product conduits and service conduits,
The underwater piping 10 has a high pressure (for example, about 1000~
50000 kPa, preferably at least 5000 kPa) and sealed during transport to the installation site. Undersea pipe 10 with buoy 11 attached
is placed in position between the connection points 1, 2 while the lowering cable is attached and operated to pull each terminal assembly of the subsea pipe 10 to the respective seabed connection points 1, 2. , is retained. Buoy 1
1 is released, the underwater pipe 10 connects to the connecting point 1,
2 to be deposited in place along the ocean floor for connection. A test meter then connects the fluid conduit 10,1
2 can be read to determine whether it held pressure during shipping and installation.

After pulling the subsea pipe 10 to its subsea location and releasing the floating buoy 11, the individual fluid conduits 10, 12 are examined to determine their ability to hold high pressures. I can do it. If no leakage is detected, one end can be connected to a well head 1 or similar connection point. Drilling through the rear of the rear block member 36 of the test cap 30 to the cylinder chamber 40 allows fluid to be pumped through each fluid conduit 10,12. This means that
This is an important feature to determine whether the service conduit can pass TFL tools during subsequent production. At the opposite end, pumping the TFL tool from the production station via the end connected to the test cap 30 of the partially laid subsea pipeline 10
provides valuable information about continuity and ensures production capacity. By reversing the flow of fluid through the test cap 30, the TFL tool can be returned to the end connected to the test cap 30. After testing for leaks and functional integrity, the remaining test caps 30 may be depressurized. A retrieval line is then attached to the latch sleeve 39 of the test cap 30 and sufficient lateral force is applied to break the shear pin 35. Piston assembly 50 as a leak-proof assembly
does not protrude beyond the front inner surface of the aft block member 36 of the test cap 30, so the test cap 30 is easily removed without damaging the end assembly of the subsea pipe 10; , which can then be connected to the permanent connection joint in a known manner. Test caps can be collected for reuse.

Effects of the Invention Since the present invention has the above-described configuration and operation, the integrity and fluid handling ability of the underwater piping can be checked in advance before it is laid at a predetermined location on the seabed. Since it is possible to test
This allows for the detection and removal of damaged, non-functioning, or highly dangerous subsea piping before connecting each terminal assembly to each connection point on the seabed. Therefore, it is possible to avoid wasteful costs caused by installing such defective underwater piping, which is an excellent effect.

[Brief explanation of drawings]

Fig. 1 is an explanatory diagram showing the subsea pipe during the lowering operation, Fig. 2 is a partially cutaway front view showing the terminal assembly of the subsea pipe, and Fig. 3 is the terminal assembly of the subsea pipe. FIG. 4 is a partially cut-away front view of an embodiment of a test cap according to the invention placed on top of the front view of an embodiment of a test cap according to the invention shown in FIG. 5 is a front view of the first piston assembly of the test cap shown in FIG. 4; FIG. 6 is a cross-sectional view taken along line 6-6' of FIG. 5;
7 is a front view of the second piston assembly of the test cap shown in FIG. 4; FIG. 8 is a cross-sectional view taken along line 8-8' of FIG. 7; and FIG. The front view of the third piston assembly of the illustrated test cap, FIG. 10, is a cross-sectional view taken along line 10-10' of FIG. 1, 2... Connection point, 10... Undersea pipe, 10
a, 12a...Fluid passage, 10, 12...Fluid conduit, 20...Mandrel, 24...Inner mounting collar, 30...Test cap, 34...Front yoke plate, 35...Shear pin, 36 ... Rear block member, 40, 41, 42 ... Cylinder chamber, 5
0,150,250...Piston assembly, 53...
...Guide hole, 56...Central fluid passage, 60...Spring, 70, 72, 170, 270, 272...O
ring.

Claims (1)

[Claims] 1. In a test cap for an underwater pipeline to be attached to an underwater pipeline consisting of a plurality of conduits, between a rear block member having a flat inner surface and a flat inner surface of the rear block member. a forward yoke plate adapted to bear directly on its rear face on its inwardly mounted collar for receiving the terminal assembly of a subsea conduit consisting of a number of conduits; a number of cylinder chambers coaxially aligned with the conduit in the inner mounting collar of the conduit opening into the inner surface and pressing directly against the front yoke plate; When used with an equal number of piston assemblies mounted for axial movement within each cylinder chamber, each cylinder chamber behind the piston assembly mounted within each cylinder chamber is arranged within an aligned conduit. is in communication with the conduit in the inner mounting collar and is pressurized to allow the piston assembly to join the inner mounting collar of the conduit and to test the structural integrity of the conduit. A test cap for an underwater pipeline, characterized in that it consists of means. 2. The test for underwater pipelines according to claim 1, wherein the means for pressurizing each cylinder chamber consists of one or more fluid passages extending longitudinally through each piston assembly. Cap. 3. A subsea pipeline test cap as claimed in claim 1 or 2, wherein the piston assembly is biased by a spring towards the flat inner surface of the rear block member. 4. Each piston assembly has an O-ring in its outer surface, thereby making the piston assembly leaktight against the inner mounting collar of the conduit. Test cap for underwater pipelines as described in item 2 or 3. 5 Each piston assembly has one
A test cap for an underwater pipeline according to any one of claims 1 to 4, which has one or more O-rings, thereby preventing leakage of the piston assembly to the cylinder chamber. . 6. A test cap for a subsea pipeline as claimed in any one of claims 1 to 5, including means for retaining the test cap in an internally mounted collar of the pipeline. 7. Means for retaining the test cap in the inner mounting collar of the conduit, extending rearwardly from the front yoke plate and adapted to be engaged by a slit collar above the conduit; or It consists of a number of shear pins that, when a lateral force is applied to the test cap, allow the test cap to be released from the conduit.
7. A test cap for an underwater pipeline system according to claim 6, wherein the test cap is adapted to be sheared by said slit collar. 8. A subsea device according to any one of claims 1 to 7, having a latch sleeve, by means of which a release force can be applied in order to remove the test cap from the conduit. Test cap for pipelines.