BR112019021440B1 - PIPE TENSIONER, METHOD OF MONITORING LOADING BETWEEN A SUBSEA DUCT AND A PIPE TENSIONER, AND MARINE PIPE LAUNCH ASSEMBLY - Google Patents

Abstract

A pipeline tensioner for launching or recovering a subsea pipeline comprising at least two opposing continuous rails capable of containing the subsea pipeline, wherein each rail has a plurality of blocks mounted on the continuous rail to contact the pipeline. submarine, characterized in that at least one block is a cargo block comprising one or more load sensors for measuring the loading on the cargo block during handling of the subsea pipeline.

Description

BACKGROUND

[0001] Submarine marine pipelines are well known in the art to transport fluids, for example hydrocarbons, such as oil and gas. Such pipelines may be laid on a seabed or seabed to pass fluids between two locations, such as a production well or a wellhead and an adjacent production platform. Such pipelines also need to be recovered from the seabed after use.

[0002] Three methods of launching a pipeline are employed and depend on the depth of the seabed. A first method, called J Lay, consists of building the pipeline on a vertical assembly line and launching it in a vertical position. This method is particularly suitable for laying pipelines underwater in very deep waters (generally a depth greater than 1500 m). When the seabed is not very deep (generally a depth less than 1500 m), in a second method called S Lay, the pipeline is laid in a horizontal configuration. Subsea pipelines are generally laid from a pipeline laying vessel, sometimes called a marine pipeline laying vessel. When the pipeline has sufficient flexibility, a third method can be employed in which the pipeline can be formed 'onshore' and located on a large storage drum or spool on the pipeline laying vessel for subsequent 'sea' launching directly from the pipeline. reel. This is generally called 'reel casting' in the technique. To do this, the duct needs to be spooled or wound on both the spool and the back of the spool, based on controlled movement, which can be provided by a suitable tensioning assembly.

[0003] For launching, the pipeline laying vessel usually has a marine pipeline launching assembly thereon, such as a tower, for organizing the pipeline from the vessel to the sea. The marine pipeline launching assembly may control the direction, speed and/or other parameters of the pipeline during its launching operation, and movement between the pipeline and the vessel is generally controlled by one or more apparatus or devices intended to grasp and/or apply tension to the pipeline as it passes through the marine pipeline laying assembly. Devices and apparatus suitable for this purpose are known as “tensioners”.

[0004] An example of a tensioner is shown in document FR2964441B1. Figure 1 of that prior patent is reproduced as Figure 1 of the accompanying drawings. Referring to Figure 1, the tensioner (1A) comprises multiple continuous rails (10A) that are adapted to engage the duct and support at least the weight of the duct. The rails (10A) are each supported by a chassis (13A) which is mounted on a support structure (20A) by cylinders (26A). The cylinders (26A) provide relative movement of the rails (10A) in order to provide clamping force from the rails (10A) to the duct. This allows the duct to be held in place by friction between the rail (10A) and the outer surface of the duct. Each rail (10A) comprises multiple pipe tensioner blocks (16A) on its outer surface that contacts the pipe. Friction is provided by the outer surface, that is, the surface that comes into contact with the piping of each block, which is formed from steel with a rough surface or grooves or from a material that has a relatively high coefficient of friction, such as rubber or polyurethane. . This surface contacting the pipe, and in particular in the case of the non-steel surface contacting the pipe, is attached to a rigid back plate, or support, in order to provide the tensioner block of piping with the necessary mechanical resistance. This backplate is conventionally made of steel.

[0005] The clamping force applied by the tensioner to the pipeline is a key parameter in pipeline laying. Excessive clamping force may damage the duct. On the contrary, insufficient clamping force can lead to inadequate and unstable pipeline clamping, and movement of the pipeline in an uncontrolled manner can damage the pipeline and affect the safety of nearby users or operators. Therefore, it is beneficial to measure the clamping force applied by a tensioner.

[0006] It is known to measure the clamping force applied by a tensioner with the use of 'test pipes' which have an integrated stress gauge, so that the stress gauge once inserted into a pipe tensioner records location variations in the block loading. However, this is a distinct and indirect methodology, and cannot provide any information regarding variations in the pipelines passing through the pipe tensioner. For example, most pipelines to be laid underwater, such as rigid pipelines, are formed from a series of piping 'rods' welded to each other with the welding zone coated to provide additional protection around a weld. . This is known as ‘field joint coating’. However, the field joint lined section is typically thicker than the other parts of the pipeline, which will create a change in required clamping force that the operator needs to consider as the pipeline diameter varies during pipeline laying. Furthermore, axial and lateral loads cannot be measured with such a methodology, but such values would provide beneficial guidance on block behavior, and thus on the efficiency of pipe handling by the tensioner.

[0007] An object of the present invention is to provide an improved pipeline tensioner and a pipeline loading monitoring method capable of providing 'real-time' information.

PRESENTATION OF THE INVENTION

[0008] According to one aspect of the invention, a pipeline tensioner for launching or recovering a subsea pipeline comprising at least two opposing continuous rails capable of containing the subsea pipeline is provided, wherein each rail has a plurality of blocks mounted on the continuous rail for contacting the subsea pipeline, characterized in that at least one block is a load block comprising one or more load sensors for measuring loading on the load block during handling of the subsea pipeline.

[0009] According to a second aspect of the invention, a method of monitoring loading between a subsea pipeline and a pipeline tensioner for launching or recovering the subsea pipeline is provided, wherein the pipeline tensioner comprises at least two opposing continuous rails capable of containing the subsea pipeline, and each rail has a plurality of blocks mounted on the continuous rail for contacting the subsea pipeline, comprising at least the steps of: providing at least one block as a load block comprising one or more load sensors to measure loading on the cargo block during subsea pipeline handling; and measuring the loading on the load block or each load block.

[0010] According to a third aspect of the invention, a marine pipeline launching assembly comprising a pipeline tensioner is provided as defined herein.

[0011] Optionally, the present invention also provides a method of launching or recovering a marine pipeline from or to a pipeline laying vessel, wherein the vessel comprises a marine pipeline laying assembly comprising a pipeline tensioner as per defined above, wherein the method comprises the steps of: (a) delivering the pipeline through the marine pipeline launch assembly, (b) contacting an external surface of the pipeline with the blocks, wherein at least one block is a payload block comprising one or more load sensors for measuring loading on the payload block during handling of the subsea pipeline and (c) moving or holding the pipeline in the marine pipeline laying assembly to assist in launching or recovering the pipeline .

[0012] Optionally, the present invention also provides a method of coiling a marine pipeline to or from a spool, wherein the method comprises the steps of: (a) delivering the pipeline through a pipeline tensioner comprising a plurality of blocks, wherein at least one block is a load block comprising one or more load sensors for measuring loading on the load block during handling of the subsea pipeline, (b) contacting an external surface of the pipeline with the surface that contacts the pipeline of or from each block, and (c) moving the pipeline to or from the spool.

BRIEF DESCRIPTION OF THE DRAWINGS

[0013] This invention will be further described by reference to the following Figures which are not intended to limit the scope of the claimed invention, in which:

[0014] Figure 1 shows a prior art tensioner;

[0015] Figure 2 shows a pipe tensioner according to an embodiment of the invention;

[0016] Figure 3 is a perspective view of a first payload block in a pipe tensioner according to an embodiment of the invention;

[0017] Figure 4 is a detailed view of a payload sensor in the first payload block shown in Figure 3;

[0018] Figures 5a and 5b are perspective and side views of a second payload block in a pipe tensioner in accordance with an embodiment of the present invention;

[0019] Figures 6a and 6b show schematic side views of two positions of a duct passing through a pipe tensioner according to an embodiment of the invention, and

[0020] Figure 7 shows a graph of the loading versus the load block position derived from Figures 6a and 6b.

DETAILED DESCRIPTION

[0021] The present invention provides a pipeline tensioner comprising at least two opposing continuous rails for handling a subsea pipeline, typically launching the subsea pipeline from a vessel or recovering the subsea pipeline on a vessel, and typically, in, on or through a marine pipeline laying assembly, wherein at least one block on one of the pipeline tensioner rails is a load block comprising one or more load sensors for measuring loading on the load block during the handling of the submarine pipeline. In accordance with the present invention, the term “laying” encompasses all operations involved in laying subsea pipeline including, but not limited to, winding and/or unwinding a subsea pipeline on or from a spool located on a vessel. pipe laying.

[0022] The shape, design, form or arrangement of the pipe tensioner is not limiting in the present invention. A pipe tensioner typically has 2, 3 or 4 opposing continuous rails, generally in a symmetrical arrangement around a pipeline path through it. Typically, the pipe tensioner is supported by or within a tower, sometimes called a pipe laying tower, which may be part of the marine pipe laying assembly. Such a tower provides the direction or ‘line of fire’ for the underwater pipeline, especially during launch.

[0023] Handling the subsea pipeline during launch or recovery with the expected amount of control, including at an appropriate speed is an expected function of the pipeline tensioner. Optionally, this includes having the ability to contain or pause any pipeline movement when it is desired for the pipeline to perform one or more other actions during pipeline launch or recovery, such as adding an intermediate unit, device or apparatus to the pipeline, joining sections or pipeline rods, or conduct known subsea operations in a pipeline. Thus, the pipe tensioner is expected to have the ability to provide the correct amount of tension in the form of clamping force every time.

[0024] Typically, the total clamping force of the rails in the pipeline is provided by cylinders between a tensioner support structure and a chassis for each rail, and is distributed among the blocks of each tensioner rail in contact with the subsea pipeline during the launch or recovery of the submarine pipeline. The distribution of the total clamping force may be uniform or heterogeneous between each such block. This total distributed clamping force is considered to be the loading between the subsea pipeline and the pipeline tensioner.

[0025] During handling and passage of a pipeline through a pipe tensioner, the block supports one or more of the three main forms of loading, being axial loading (Fx), normal loading (Fz) and lateral loading (Fy) . Axial loading (Fx) is the component of loading parallel to the longitudinal geometric axis of the pipe. The normal load (Fz) is the component of the load oriented along the radius of the duct that joins the center of the surface that comes into contact with the block piping. Lateral loading (Fy) is the loading component orthogonal to axial loading and normal loading. These loads lead to one or more compression, shear, torsion or bending stresses on the block. The normal load on each block of continuous rails can be up to 425 kN, in general, between 50 kN and 368 kN; the axial load on each block of continuous rails can be up to 85 kN, in general, between 3 kN and 35 kN and the lateral load on each block can be up to 95 kN, in general, between 0.75 kN and 105 kN. Any variation in the duct, in particular, in the duct diameter, will clearly alter the loading between the duct and the pipe tensioner.

[0026] The shape, design, form or arrangement of the continuous pipe tensioner rails is not limiting in the present invention, and is generally in the form of an elongated arrangement around one or more end rollers or drums of a supporting chassis, at least one of which is driven by a suitable drive apparatus or mechanisms to create 'conveyor belt' type movement of continuous rails in a manner known in the art. Continuous rails and their chassis are not further described in this document.

[0027] Conventional blocks used in conventional continuous rails of a pipe tensioner are well known in the art. A conventional block typically comprises a rail support portion and a duct engagement portion. The rail supporting portion may include a base or plate, such as a base plate or a back plate, which may be rigid, and which is designed to provide engagement and gripping of the block to the continuous rail with the use of a or more fittings or accessories.

[0028] The duct engagement portion of a conventional block may have a surface that contacts the piping formed from a material with a relatively high coefficient of friction, such as rubber or polyurethane or steel. The surface that comes into contact with the pipe may also comprise a rough surface or grooves to aid engagement between the block and the pipe. The uppermost part of the duct engagement portion, like any surface that contacts the piping, may be shaped to enhance the block's contact with a duct, such as having a valley that, in use, extends in a parallel direction. to a longitudinal geometric axis of the duct that has contacted the surface and to the angled surfaces that engage the piping in a manner known in the art. The longitudinal geometric axis of the duct is that which extends along the length of the duct.

[0029] A conventional block may also have a housing disposed between a duct engagement portion and a rail support portion. Such a housing may be of any suitable shape, such as a rectangular, circular or T-shaped shape. The housing may be formed of any suitable material, such as plastics or metals. The intermediate housing may be attached to the duct engagement portion and/or the rail support portion by any means, such as pins, screw or adhesive.

[0030] A conventional block may also have a spring block between the rail supporting portion and the intermediate housing to provide the expected resilience of a block. The spring block can be any suitable shape, such as, but not limited to, rectangular, circular shape. The spring block may be formed from any suitable material, such as rubber or polyurethane. Typically, the spring block transfers the duct load to the housing, which then transfers the load to the duct engagement portion. This can be done by contact between the housing and the duct engagement portion and/or through a shear key managed on the top face of the housing.

[0031] In general, the total height of a conventional block is between 100 mm and 250 mm, in particular, between 200 mm and 250 mm. The total height is measured from the bottom of a valley line from the surface that contacts the pipe to the rail supporting portion. The length of conventional blocks is generally between 150 mm and 250 mm, and the width is generally between 200 mm and 400 mm.

[0032] In general, the stiffness of a conventional block is between 9 kN/mm and 90 kN/mm, such as between 10 kN/mm and 25 kN/mm.

[0033] The present invention is defined by at least one block of a pipe tensioner which is a load block comprising one or more load sensors. The term “load block” is used herein to define a block for a pipeline tensioner comprising one or more load sensors capable of monitoring and, preferably, providing at least one measurement of loading between a subsea pipeline and a pipe tensioner.

[0034] The load block may have any suitable shape, design, form or arrangement within the requirement of being grippable to a continuous rail, and optionally, combine with the conventional block or blocks on the continuous rails.

[0035] Optionally, a load block has the same height, width and length dimensions or similar height, width and length dimensions as a conventional block, so that it can be used directly on an existing pipe tensioner through replacement of a conventional block with a load block. This also ensures that the load measured by the load block is a ‘real’ load, i.e. the same or similar to the load experienced by a conventional block, which adds to the reliability and accuracy of the measurements provided.

[0036] The present invention is not limited to several load blocks added to each, or some, or all of the continuous tracks of the duct tensioner. A pipeline tensioner having a plurality of continuous rails may comprise a different number of load blocks on each or some or all of the continuous rails, including no load blocks. Optionally, each block of at least one of the continuous tracks, optionally both continuous tracks, is a load block. Additionally and optionally, each block of a continuous rail is a load block.

[0037] Load sensors for measuring loading are well known in the art. Typically, a load sensor includes a transducer that creates an electrical signal whose magnitude is proportional, typically and directionally proportional, to the force that is applied to the load sensor. The electrical signal emitted can be one or more of the group comprising: a voltage change, a current change or a frequency change, depending on the load sensor that is used. Any electrical signal is typically small, e.g., in the magnitude of millivolts, etc., and typically requires amplification. Load sensors can be supplied in a range of shapes, sizes and dimensions.

[0038] Optionally, at least one load block measures one or more of the group comprising: axial loading (Fx), normal loading (Fz) and lateral loading (Fy).

[0039] Optionally, the load block has the same way of fixing and gripping a continuous rail as a conventional block. Optionally, the or each load block used in the present invention comprises a rail supporting portion and a duct engagement portion. The rail supporting portion may include a base or a plate, such as a base plate or a back plate, in particular, which is rigid, and which is capable of providing engagement and gripping of the load block to the continuous rail. The rail supporting portion may include one or more fittings, fittings or openings capable of permitting one or more engaging parts, such as threads, screws, pins, hooks or other fasteners, to achieve engagement and gripping of the load block with the continuous track.

[0040] The pipeline engagement portion preferably has a surface that contacts the pipeline formed from a material with a relatively high coefficient of friction, such as rubber or polyurethane. Optionally, the uppermost portion of the duct engagement portion, like any surface that contacts the piping, is shaped to enhance contact of the load block with a duct, such as having a valley and angled surfaces that engage the pipeline. a manner known in the art.

[0041] Optionally, the inner surface of the surface that contacts the pipe is shaped or machined to fit one or more load sensors.

[0042] Optionally, the outer surface of the surface that contacts the piping of a charging block is the same as a conventional block.

[0043] The or each load sensor of a load block may be located at any approximate suitable location and/or on and/or within the load block. Optionally, the or each load sensor has the ability to measure loading on the duct engaging surface of the duct engaging portion. Optionally, at least one load sensor is located between the rail bearing portion and the duct engagement portion.

[0044] According to one embodiment of the invention, load sensors are located within the duct engagement portion of a load block.

[0045] Optionally, the load block further includes an intermediate portion between a rail support portion and a duct engagement portion, said intermediate portion including a housing or housings for one or more load sensors. The housing or housings may be formed integrally with any rail bearing portion or any duct engagement portion or both.

[0046] Thus, according to another embodiment of the invention, the load sensors are located between the duct coupling portion and the intermediate portion of a load block.

[0047] Optionally, there is no contact between the rail support portion and a duct engagement portion other than through the load sensor or each load sensor. This provides a more accurate measurement or measurement of the load or loads by the load sensor or each load sensor. Preferably, there is at least one gap between the rail supporting portion and the duct engaging portion.

[0048] Optionally, one or more of the group comprising a rail support portion, a duct engagement portion and an intermediate portion are separable. A rail support portion and a duct engagement portion and any intermediate portion may be releasably or non-releasably secured together with the use of gripping means, including one or more of the group comprising: adhesives, pins, screws , threads and fasteners. According to the example in which the gripping means are pins, screws or threads, the load block preferably comprises 4 gripping means.

[0049] In one embodiment of the present invention, there is a load sensor located between the intermediate housing and the duct engagement portion, and the gap between the intermediate housing and the duct engagement portion, to ensure that the total load is transferred to the load sensor. Such an arrangement has an additional advantage of reducing the need to frequently remove the load sensor due to wear of the duct engagement portion. According to the example in which the gripping means are pins, screws or threads, said gripping means preferably comprises a rod extending through a hole formed in the duct engagement portion. Preferably, there is also a gap between the orifice and the rod to prevent the rod from bearing loads during handling of the duct, wherein the general loads that are transferred from the duct engagement portion to the intermediate portion through the load sensors.

[0050] Optionally, at least one load sensor is a load cell. Optionally, the load cell is a three-axis load cell. The compressive stiffness of the load cell must be at least greater than the compressive stiffness of a conventional block. This should achieve more accurate and reliable measurement of loading. The total stiffness of the load block must be the same or similar to the total stiffness of a conventional block, such as within +/- 1% of the stiffness of the conventional block.

[0051] Optionally, the or each load block has at least 3 load sensors to increase the sensitivity of the load block. Additionally and optionally, the or each load block has 4 load sensors to enhance the stability of the load block. Preferably, the four load sensors are located symmetrically within the load block.

[0052] Optionally, the pipe tensioner comprises one or more means of data recorders/storage, data transmitters or both.

[0053] Data generated by a payload block may be stored on any suitable storage medium/data recorder that may be near and/or on and/or on the payload block, or could be transmitted via any transmission medium suitable, wired or wireless, from the load block to a separate location for storage and/or processing, or for additional relaunch, or any combination thereof.

[0054] A data storage medium/recorder may comprise any form of data recording or memory device or apparatus, typically a chip or memory device or the like, capable of recording and/or storing data for subsequent processing. Optionally, data on a data recorder is downloaded or retransmitted to an appropriate receiver for storage and/or processing and/or retransmission or transmission.

[0055] Optionally, a data transmitter includes one or more transmitters, optionally, with an antenna, capable of transmitting data from the payload block to an appropriate receiver. An example includes wireless transmission to a wireless receiver partially or completely located on or adjacent to or remote from the pipe tensioner. Examples of wireless data transmission technologies include, but are not limited to, Wi-Fi, based on IEEE 802.11 standards, and Bluetooth.

[0056] Optionally, the pipe tensioner includes one or more relay units or apparatus, capable of relaying data or other information from the load block to one or more remote locations, such as the user or operator of the pipe tensioner, or a suitable control space or remote control location via any suitable transmission means, wired or wireless.

[0057] Optionally, the load block comprises a wireless data transmitter. Optionally, the wireless data transmitter is releasably secured to the intermediate housing. The wireless data transmitter may transmit real-time or main memory-stored data generated by the payload block, or data that was stored locally by the payload block prior to transmission. Data may be transmitted from the payload block to any one or more of the aforementioned data storage/recorder media or relay units or the like.

[0058] Optionally, the load block comprises a power pack to supply power to the wireless data transmitter. Optionally, the power pack is releasably secured to the intermediate housing. Optionally, the wireless data transmitter and power pack are releasably secured to opposite sides of the intermediate housing to enhance the stability of the payload block.

[0059] The present invention also provides a method of monitoring loading between a subsea pipeline and a pipe tensioner as described above.

[0060] Subsea pipelines were initially discussed in the present document, and are typically elongated, optionally have a length of many meters, including many kilometers, with a regular and typically circular outer surface. The outer surface of the subsea pipeline is typically one or more protective coatings or sheaths, generally a polymeric protective sheath, against which the blocks of a pipeline tensioner engage. The subsea pipeline may be for transporting fluids and/or other services underwater, including subsea or seabed communications or chemical supply. The present invention is not limited by the nature of the subsea pipeline. Thus, the subsea pipeline includes a rigid subsea pipeline as well as a flexible subsea pipeline.

[0061] In the method of monitoring load, at least one of the blocks of at least one of opposing continuous rails is a load block comprising one or more load sensors. The nature and action of a load block and a load sensor are described herein, and apply equally to the method of measuring load according to the present invention.

[0062] The method also comprises the step of measuring the load on the load block or on each load block. The measurement may be performed using any suitable process or arrangement, typically based on loading between a subsea pipeline and the load block causing a deformation or strain on the one or more load sensors, which may provide a measurement, for example, in the form of one or more electrical signal emissions, which can be measured and, preferably, recorded, locally or remotely.

[0063] Optionally, the method of the present invention further comprises the step of retransmitting the load measurement to another processor and/or location.

[0064] The loading measurement may comprise a single figure or value, or may comprise a plurality of measurements or values, which may be processed individually or processed in an aggregated manner, to provide a final measurement or data set.

[0065] For example, a measurement of 'normal' loading can help indicate how the tightening force of the tensioner is distributed in the pipeline. Such information can help detect any overload in a block or pipe, such as a field joint coating zone or a lack of tightness.

[0066] And/or a measurement of the axial load can help indicate how the total clamping force is supported, and how it is distributed between each block and/or within a block and/or in the piping.

[0067] Furthermore, during pipeline laying, wave movement can result in large and repetitive tensile stress variations of the pipeline that can lead to fatigue of said pipeline. Therefore, axial load measurement can help provide guidance on tensile stress during pipeline laying and thus a better understanding of pipeline fatigue during laying. Such data can subsequently be used to validate the piping design or to improve its design for future projects. In the meantime, a measurement of lateral loading can help indicate the distribution of clamping force within a block.

[0068] According to an embodiment of the present invention, the method of the present invention further comprises real-time measurement of loading. Real-time measurement can be performed intermittently, continuously, or a combination thereof, optionally with regular or irregular periodic frequency, or periodic changes therebetween. Optionally, the operator of the pipe tensioner has the ability to measure the loading between a subsea pipeline and the pipe tensioner in a predetermined arrangement, regime or sequence while handling the subsea pipeline passing through the pipe tensioner. Optionally, the time or timing of the loading measurement is variable during use of the pipe tensioner to allow the operator to vary the measurement, and to have variation in the data provided by the method of the present invention.

[0069] Optionally, the method of the present invention comprises continuously measuring the loading, in particular, during the passage of a subsea pipeline through the pipe tensioner.

[0070] Optionally, the method of the present invention further comprises the steps of: providing at least one block as a load block capable of measuring one or more of the group comprising: axial loading, normal loading and lateral loading; and measuring one or more loads on the load block.

[0071] The nature and design of the one or more load blocks are described in the present document, and apply equally to the method of the present invention.

[0072] Optionally, the method of the present invention comprises measuring and recording the loading of each load block on the pipe tensioner.

[0073] Optionally, the method of the present invention comprising measuring the loading along at least one geometric axis of the load block, additionally or optionally, all three geometric axes of the load block.

[0074] Optionally, the load block comprises a rail supporting portion and a duct engagement portion, and the method of the present invention further comprises the step of locating one or more load cells between the rail supporting portion and the duct coupling portion, which transfers the total load from the rail supporting portion to the duct engagement portion through the one or more load cells, and which measures the loading on the load block using the one or more or more load cells. The nature and design of a rail supporting portion and a duct coupling portion are described herein, and apply equally to the method of the present invention. Additionally and optionally, the load block includes an intermediate portion, which optionally has a housing for one or more load cells as further described herein.

[0075] Optionally, the method of the present invention further comprises the steps of: moving a subsea pipeline through the pipe tensioner with the use of opposing continuous rails; and monitor the passage of the subsea pipeline through the pipe tensioner based on measuring the loading on the load block or on each load block.

[0076] Optionally, the method of the present invention comprises a tensioning duct that has at least two, such as two or four, opposing rails, each rail having at least one load block in a symmetrical and opposite position, and which additionally comprises the steps of: moving a subsea pipeline through the pipe tensioner with the use of the opposing continuous rails; and monitor the load on the tensioner during engagement of the symmetrical and opposing load blocks against the duct.

[0077] The present invention also provides a marine pipeline launching assembly comprising a pipeline tensioner as defined herein. Typically, the marine pipeline laying assembly includes a tower, which tower includes the pipeline tensioner. The marine pipeline laying assembly is typically arranged on a seagoing vessel, which is a ship or a barge or the like, and may also be movable, in particular, rotational to provide an 'angled' pipeline laying direction relative to to a vessel. The marine pipeline launch assembly may include one or more other supports, chassis, or pipeline tensioners in line with the pipeline tensioner of the present invention.

[0078] Figure 2 shows a simplified version of a pipeline tensioner 30 that is similar to the tensioner 1A shown in Figure 1, and which comprises multiple continuous rails 32 that are adapted to engage a subsea pipeline (not shown) and support at least the weight of the duct as it moves in direction F as shown or in the opposite direction.

[0079] The continuous rails 32 are driven by motors (not shown), and are each supported by a chassis 34 mounted on a support structure 36 by cylinders 38. The cylinders 38 provide relative movement of the rails 32 in order to provide clamping force between the rails 32 and the duct.

[0080] Each continuous rail 32 comprises multiple conventional pipe tensioner blocks 40, and wherein at least one load block 42 comprises one or more load sensors, examples of which are described hereinafter.

[0081] The pipeline tensioner 30 may be part of a marine pipeline launching assembly.

[0082] Figure 3 shows a first payload block 70 useful in the present invention. The first load block 70 has a duct engagement portion 72, an intermediate housing 74, and a base plate 76. The first load block 70 also has a spring block 90.

[0083] The duct engagement portion 72 may be formed from an upper casting, which typically has a valley-line shape to aid engagement of a duct in use.

[0084] The intermediate housing 74 houses four load cells 80 located between an upper surface of the intermediate housing 74 and the duct engagement portion 72. In particular, each load cell 80 is bolted to the intermediate housing 74 and the engagement portion of duct 72.

[0085] The first load block 70 can be used as the load block 42 in the pipe tensioner 30 shown in Figure 2. The base plate 76 of the first load block 70 includes openings for gripping the first load block 70 to a continuous trail. The spring block 90 is clamped between the base plate 76 and the intermediate housing 74. The spring block 90 has a rectangular body with a central hollow core.

[0086] Figure 3 also shows the first load block 70 which has a power pack 86 and a wireless transmitter 88. The power pack 86 can provide the power required to operate the wireless transmitter 88. The wireless transmitter 88 provides the ability to send a measurement or data in the form of a signal to a suitable data recorder for processing, or to a suitable relay near the pipe tensioner. The power pack 86 and wireless transmitter 88 are secured to the sides of the intermediate housing 74 by screws 84.

[0087] Figure 4 shows a detail of a load cell 80 in Figure 3, in which the load cell 80 is a separable unit from the remainder of the first load block 70, and therefore can be removed in the event of failure. . This also enables easier calibration of the load cell 80 prior to its installation within the first load block 70, on or with a test test stand.

[0088] The load cell 80 may comprise a main core 100 that has a cross section that is or is nearly constant. The main core 100 generally has a cylindrical shape. The main core 100 preferably comprises top and bottom covers 101, and at least one support or foundation 102 located between the covers 101. Optionally, the main core 100 comprises at least two foundations 102; more optionally, four foundations 102, generally in a symmetrical configuration between the top and bottom covers 101 as shown in Figure 4.

[0089] Optionally, the cross-section and height of the foundation or each foundation 102 enable an accurate measurement of the load imposed on the load cell 80.

[0090] In one embodiment of the present invention, the main core of the load cell 80 is machined from a single piece or block of material, for the purpose of forming a unitary assembly. For example, the top and bottom covers 101 and foundations 102 shown in Figure 4 could be formed from a single block of suitable material.

[0091] Figure 4 shows a transducer 104 fixed to each foundation 102. In general, the load applied to the first load block 70 leads to a change in electrical resistance of the transducers 104 that is proportional and/or directly proportional to the applied load. As various parameters (such as temperature) can also induce variation in electrical resistance, the transducers 104 are preferably arranged to compensate for any variation in electrical resistance induced by such parameters other than the load. Therefore, the final measurement is preferably not affected by temperature or other such parameters.

[0092] Figures 5a and 5b show a second load block 110 that has a rail support portion 112, a duct engagement portion 114 and a load sensor 116 located between the rail support portion 112 and the duct engagement portion 114. The duct engagement portion 114, the load sensor 116, and the rail support portion 112 may all be machined from a workpiece or block of suitable material, such as, but not limited to, steel. In this way, the duct engagement portion 114, the load sensor 116 and the rail support portion 112 are thus fixed together to provide a more robust and compact load block.

[0093] Optionally in a second load block 110, the load sensor 116 comprises one or more foundations 118, wherein each foundation 118 optionally has one or more transducers 120 therein. In general, the load applied to the load block 110 leads to a change in electrical resistance of the transducer (or transducers) 120 that is proportional and/or directly proportional to the applied load. Again, as various parameters (such as temperature) can also induce variation in electrical resistance, the transducers 120 are preferably arranged to compensate for any variation in electrical resistance induced by such parameters other than the load. Therefore, the final measurement is preferably not affected by temperature or other such parameters. Typically, there are multiple transducers 120 per foundation 118, typically five transducers per foundation 118. Having multiple transducers per foundation can provide an improved or more accurate assessment of overall rail performance.

[0094] Optionally, the load sensor comprises six to nine foundations. Figures 5a and 5b show the second load sensor which has nine foundations 118. The number, cross-section and height of the foundation or each foundation allow for an accurate measurement of the load.

[0095] Figures 6a and 6b show schematic views of a method of monitoring loading between a subsea pipeline 200 and two opposing continuous rails 202 of a pipe tensioner (not otherwise shown), such as the pipe tensioner shown in Figure two.

[0096] Figures 6a and 6b diagrammatically show each continuous rail 202 having several conventional tensioner blocks 204, and a load block 206 comprising one or more load sensors in accordance with the present invention, (such as the first and according to load sensors 70, 110 described previously in this document). The load blocks 206 are in a symmetrical and opposite position.

[0097] Figures 6a and 6b diagrammatically show the movement of opposing rails 202 in a known manner, typically, in opposite symmetrical motion, to move the duct 200 downward between them in a manner known in the art.

[0098] Figure 6a shows the movement of the load blocks 206 of the present invention to initially engage with the duct 200 and move along with the duct 200, until they disengage with the duct 200 as in Figure 6b after displacement of the length of the coupling portion of the pipe tensioner.

[0099] Thus, Figures 6a and 6b show the movement of a subsea pipeline 200 through the pipe tensioner with the uses of opposing continuous rails 202, and the monitoring of the passage of the subsea pipeline 200 through the pipe tensioner based on measurement of loading on or in each load block 206 by monitoring the loading on the tensioner during engagement of the symmetrical and opposing load blocks 206 against the duct 200. Optionally, the method comprises measuring the compressive and shear loads on the load blocks 206.

[0100] Figure 7 shows a continuous and, optionally, real-time graph of the continuous measurement of load by the load blocks 206 against the position of the pipeline as it passes through the pipe tensioner (and/or against time). . The peaks show the positions of the supporting hydraulic cylinders. Thus, Figure 7 shows an initial 'zero' loading for the arrangement shown in Figure 6a, with the loading rising rapidly to a first peak when the load blocks 206 first engage the duct 200. The first peak is followed by a small reduction in loading when the load block 206 moves downward with the duct 200 between Figures 6a and 6b, followed by a second peak when the load block 206 disengages from the duct 200 shown in Figure 6b.

[0101] Figure 7 shows a compressive loading profile along a pipeline, which allows an operator or user to understand how loading occurred for that pipeline, and confirm its suitability, or how the tensioner could perform for the same pipeline or similar duct. This information may be provided by the operator or user modifying or replacing conventional blocks in the pipe tensioner, and different load blocks may be provided to replace different types of conventional blocks and/or work with different types of pipe tensioners.

[0102] The data in Figure 7 could be provided in real time by transmitting the load measurements to a suitable processor, such as a laptop-type computer or nearby computer, etc., optionally, through one or more relays, or the data could be stored in payload blocks 206 for subsequent downloading and processing.

[0103] The data in Figure 7 could also be used as a means to calculate or as an indication of fatigue or wear of a part of the pipe tensioner, such as the block surfaces, roller or cylinder bearings, etc., where a different loading profile is detected and/or to detect any overloading or underloading between the pipeline and the pipe tensioner. For example, the present invention could help indicate the presence of 'Field Joint Linings' as discussed in the present document, and their correct location, thickness, etc., but detect the expected variation in loading. This data could also provide information on the frictional behavior between the block and the pipe during launch.

[0104] The present invention provides a pipeline tensioner and a method capable of optionally measuring and recording both compressive loading and shear loading, and for capturing the effect of various types of ductwork on a pipeline tensioner, as opposed to a one-piece duct test pattern that has a stress gauge in it. Data recording can be completed on land or at sea during live installations, in particular based on the use of a wireless data transmitter, and allows for additional functionality such as the ability to post-process live data for monitoring of fatigue and/or load.

[0105] The present invention also facilitates the testing of long pipe tensioners, which is not possible with known test pipes, which only come in 'standard' short lengths.

[0106] The present invention also allows testing of a pipe tensioner to be performed at high pipe laying speeds, in particular, at a full or 'normal' pipe laying speed, again unlike standard test pipes.

[0107] The present invention also allows measuring a total load applied to a duct if the continuous rails are provided with sufficient load blocks in accordance with the present invention along their lengths.

[0108] The present invention allows data to show a compressive and/or shear loading profile along a length of pipeline or rail, which allows an operator or user to predict loadings of different pipeline products, including rigid piping or flexible or umbilical, especially, duct products of different diameters, and be prepared for differences in the compressive stiffness or frictional behavior of certain ducts.

[0109] The present invention can also be applied in a test environment on land, or in a test environment at sea or during launch or recovery operations at sea.

[0110] The present invention can also be used to validate predictive modeling of pipeline launch or recovery operations, enabling faster or otherwise faster actual pipeline launch or recovery operations, saving the large OPEX involved in pipeline launching or recovery operations.

Claims (21)

1. Pipe tensioner (30) for launching or recovering a subsea pipeline comprising at least two opposing continuous rails (32) capable of containing the subsea pipeline, wherein each rail has a plurality of blocks (40) mounted on the continuous rail for contacting the subsea pipeline, wherein at least one of the blocks is a load block (42) comprising one or more load sensors for measuring loading on the load block during handling of the subsea pipeline, characterized by the fact that the load block (42) comprises a rail support portion (112) and a rail engagement portion (114), and wherein at least one load sensor (116) is located in a space between the support portion (112) and the rail engagement portion (114). 2. Pipe tensioner (30), according to claim 1, characterized by the fact that each block of at least one of the continuous rails (32) is a load block (42). 3. Pipe tensioner (30), according to claim 1, characterized by the fact that at least one load block (42) measures one or more of the group comprising: axial loading, normal loading and lateral loading. 4. Pipe tensioner (30), according to claim 1, characterized by the fact that it comprises a gap between the rail support portion (112) and the rail engagement portion (114). 5. Pipe tensioner (30), according to claim 1, characterized by the fact that at least one load sensor (72) is a load cell (80). 6. Pipe tensioner (30), according to claim 5, characterized by the fact that at least one of the load cell (80) is a three-axis load cell. 7. Pipe tensioner (30), according to claim 1, characterized by the fact that the load block (42) has at least three load sensors. 8. Pipe tensioner (30), according to claim 1, characterized by the fact that the load block has four load sensors. 9. Pipe tensioner (30), according to claim 1, characterized by the fact that it additionally comprises one or more data recorders, data transmitters or both. 10. Pipe tensioner (30), according to claim 1, characterized by the fact that the load block comprises a wireless data transmitter (88). 11. Pipe tensioner (30), according to claim 1, characterized by the fact that each block of each of the continuous rails is a load block. 12. Marine pipeline launching assembly characterized by the fact that it comprises a pipeline tensioner (30) of the type defined in claim 1. 13. Method of monitoring loading between a subsea pipeline (200), and a pipeline tensioner (30) for launching or recovering the submarine pipeline, the pipeline tensioner comprising at least two opposing continuous rails (202) capable of containing the pipeline subsea, and each rail has a plurality of blocks (204) mounted on the continuous rail for contacting the subsea pipeline, characterized in that it comprises at least the steps of: providing at least one block of the plurality of blocks as a block load (206) comprising a rail supporting portion (112), a rail engaging portion (114), one or more load sensors located in a space between the rail supporting portion (112) and the rail coupling (114) for measuring loading on the cargo block during subsea pipeline handling; and measuring the loading on or in each load block. 14. Method, according to claim 13, characterized by the fact that it additionally comprises the step of retransmitting the load measurement to another location. 15. Method according to claim 13, characterized by the fact that it additionally comprises the step of recording the load measurement on the load block (206). 16. Method according to claim 13, characterized by the fact that it additionally comprises measuring the load in real time. 17. Method according to claim 13, characterized by the fact that it further comprises continuously measuring the load. 18. Method according to claim 13, characterized by the fact that the load block is capable of measuring one or more of the group comprising: axial loading, normal loading and lateral loading, and the method further comprises measuring one or more of axial loading, normal loading and lateral loading. 19. Method according to claim 13, characterized in that it further comprises the steps of: locating one or more load cells between the rail supporting portion and the rail engaging portion, transferring the general load of the portion of rail support for the rail engagement portion through the one or more load cells; and measuring the loading on the load block using the one or more load cells. 20. Method, according to claim 13, characterized by the fact that it further comprises the steps of: moving the subsea pipeline (200) through the pipe tensioner (30) using the opposing continuous rails (202); and monitoring the passage of the subsea pipeline through the pipe tensioner based on measuring the loading on the load block (206). 21. Method according to claim 13, characterized in that the pipe tensioner (30) has two or four opposing rails (202), each rail has at least one load block (206) in a symmetrical position and opposite with each other of the rails, and further comprises the steps of: moving the subsea pipeline (200) through the pipeline tensioner using the opposing continuous rails; and monitor the load on the tensioner during engagement of the symmetrical and opposing load blocks against the duct.