FR3040726A1 - DEVICE FOR FORMING AN UPPER COLUMN FOR TRANSPORTING PETROLEUM PRODUCTS FROM A MARINE BASE TO A COLLECTOR STRUCTURE - Google Patents

Abstract

Device for forming a riser for transporting petroleum products from a seabed to a collecting structure, or vice versa. The device comprises a plurality of sections (28) connected mechanically and successively to each other in a longitudinal direction (Z), each section comprising: - optionally a stiffening structure (30) of the riser, - at least two, preferably at least three transport ducts (32A, 32B, 34A, 34B), and - an outer casing (40) having at least two parts (40A, 40B) fixed to one another so as to surround the ducts transport (32A, 32B, 34A, 34B) about the longitudinal direction, the outer casing having a section along a cutting plane (P) perpendicular to the longitudinal direction, said section being oblong.

Description

Device for forming a riser for transporting petroleum products from a seabed to a collecting structure

The present invention relates to a device for forming a riser for transporting petroleum products from a submarine bottom to a collecting structure, for example treatment of these petroleum products. The invention also relates to a method for constructing and installing such a device on an assembly ramp located on the ground or on a floating structure.

The riser tower (or riser tower) comprises a bundle of oil lines for transporting fluid between the sea floor and a boat at the sea surface, at great depth, typically beyond one kilometer or more. The risers make it possible to raise production fluids (oil, gas) from the seabed and to send to the seabed injection products (water, gas, oil).

In the beam, the oil lines are held together and approximately parallel. The beam configuration is approximately circular in cross-section to allow better hydrodynamic behavior of the riser. The assembly of the bundle of lines arranged in a circular manner is traditionally on land sites equipped with heavy assembly means and expensive, because few.

An object of the invention is therefore to provide a device for forming a riser whose construction is cheaper and which maintains an acceptable hydrodynamic behavior. For this purpose, the invention relates to a device for forming a riser for transporting petroleum products from a seabed to a collecting structure, or vice versa, the device comprising a plurality of sections connected mechanically and successively to each other according to a longitudinal direction, each section comprising: - optionally a stiffening structure of the riser, - at least two, preferably at least three, transport ducts, and - an outer casing comprising at least two parts fixed on one side another so as to surround the transport ducts around the longitudinal direction, the outer casing having a section along a cutting plane perpendicular to the longitudinal direction, said section being oblong.

According to particular embodiments, the device comprises one or more of the following characteristics, taken (s) according to all the technically possible combinations: - the sections are substantially similar to each other; said section of the outer envelope has a larger dimension in a transverse direction perpendicular to the longitudinal direction, and a width in a second transverse direction perpendicular to the longitudinal direction and the transverse direction, the largest dimension being greater than or equal to at 1.3 times the width, preferably 1.5 times the width; the two parts of the outer envelope are substantially symmetrical to one another with respect to a median plane perpendicular to the plane of section; - At least one of the two parts of the outer casing has, in the cutting plane, a cradle shape preferably having a substantially flat bottom; the outer envelope has, in the plane of section, two opposite ends in a transverse direction perpendicular to the longitudinal direction, each of the two ends preferably being substantially semicircular; - For each of the sections, the transport pipes are substantially parallel to a given alignment plane, and are traversed by the alignment plane. The invention also relates to a method of constructing and installing a device as described above, comprising the following steps: on an assembly ramp, obtaining a first section of the device, the first section being already assembled, and obtaining a second portion partially assembled and mechanically connected to the first section, the second partially assembled section comprising one of the two parts of the outer envelope, said portion being in the longitudinal extension of the first section and receiving the transport ducts of the second section mechanically connected to the first section, - supply of one of the two parts of the outer casing, possible supply of the stiffening structure, and supply of the transport ducts of a third section to be connected mechanically in the second section, - setting up of the said two parts the outer envelope of the third section on the assembly ramp, said part being placed in the longitudinal extension of the second partially assembled section and being adapted to form a receptacle of the transport pipes of the third section, - installation of the pipes of transporting the third section in said portion, and putting in mechanical connection the transport pipes of the third section, respectively with the transport pipes of the second section partially assembled to obtain a third partially assembled section, - supply of the other of the two parts of the outer envelope of the second portion partially assembled, and - fixing the other of the two parts on one of the two parts of the outer envelope of the second partially assembled section to obtain a second newly assembled section.

According to a particular embodiment, the method in which the assembly ramp is located on a floating structure, further comprises the step of pushing longitudinally relative to the assembly ramp the first section already assembled, the second section newly assembled and the third portion partially assembled, so as to free a space on the ramp for the assembly of an additional section. The invention will be better understood on reading the description which follows, given solely by way of example and with reference to the appended drawings, in which: FIG. 1 is a schematic view of an offshore oil installation comprising a device according to the invention, - Figure 2 is a perspective view of a portion of a portion of a portion of the device shown in Figure 1; - Figure 3 is a top view of a device adapted to perform the construction of the device shown in Figure 2, and its launching, and - Figures 4 to 10 are side views of an assembly ramp located on the construction equipment shown in Figure 3, illustrating steps of a method of construction and installation according to the invention.

Referring to the figure, there is described an offshore installation 1 (offshore), which is for example intended to extract oil or gas from a seabed 5 (Figure 1). The installation 1 comprises a collecting structure 10 intended to collect and treat the petroleum products extracted from the seabed 5, and a device 15 according to the invention forming a riser (in English "riser") to transport the petroleum products to the structure collector, or convey injection products (gas, water, oil) from the collector structure to the seabed. The installation 1 also comprises a plurality of flexible ducts 20 connecting the collecting structure 10 and an upper end 22 of the device 15.

The collecting structure 10 is for example a boat, as shown in FIG. 1. In variants (not shown), the collecting structure 10 is a semi-submersible platform or with tight anchor lines.

The device 15 extends in a longitudinal direction Z between an anchor 26 in the seabed 5 and the upper end 22, which is for example a float, and which is for example at a depth Z1 of several tens of meters.

The device 15 comprises a plurality of sections 28 mechanically connected to each other successively in the longitudinal direction Z from the anchor 26 to the upper end 22.

The longitudinal direction Z is intended to be substantially vertical. Also defined is a transverse direction X perpendicular to the longitudinal direction Z, and a second transverse direction Y perpendicular to the longitudinal direction Z and the transverse direction X.

Advantageously, the sections 28 are similar to each other from the point of view of form and operation. The sections 28 form a relatively rigid structure. The sections 28 extend longitudinally over a height Z2, for example several hundred meters.

The sections 28 being similar to each other, only one of them will be described below.

As can be seen in FIG. 2, showing a portion of one of the sections 28, each section advantageously comprises a stiffening structure 30, transport pipes 32A, 32B, 34A, 34B, 36, 38A and 38B, as well as a outer casing 40 surrounding the stiffening structure 30 and the transport ducts around the longitudinal direction Z.

The stiffening structure 30 is optional. According to a particular embodiment, the stiffening structure 30 is absent and one of the pipes 32A, 32B, 34A, 34B, 36, 38A and 38B serves as a stiffening structure.

Each section 28 further comprises, in the example shown, strapping 42, for example metal or synthetic, adapted to fix one on the other two parts 40A and 40B of the outer casing 40.

The sections 28 also include connection means enabling them to be connected to one or even two sections 28 longitudinally adjacent. The connection means are, for example, connectors 44 (FIG. 4) adapted to mechanically connect the transport pipes and any stiffening structures 30 of two consecutive sections 28.

Alternatively (not shown), the connection of two consecutive sections 28 is performed by welding.

As can be seen in FIGS. 4 to 10, the two parts 40A, 40B of the outer casing 40 are advantageously constituted by the union of several elements 46, advantageously in the form of half-shells. Thus, the first portion 40A and the second portion 40B consist for example of six half-shells 46 fixed successively to each other in the longitudinal direction Z.

In a variant (not shown), the number of half-shells constituting the first portion 40A and the second portion 40B is different, for example between 2 and 50. The outer envelope 40 has an oblong section along a perpendicular section plane P in the longitudinal direction Z (Figure 2). In the example shown, said section is elongated in the transverse direction X. The section comprises a larger dimension DMAX in the transverse direction X, and a width DMIN in the second transverse direction Y.

According to a particular embodiment, the largest dimension DMAX is greater than or equal to 1.3 times the width DMIN, advantageously 1.5 times the width DMIN.

The two parts 40A and 40B of the outer envelope 40 are for example substantially symmetrical to each other with respect to a median plane P 'perpendicular to the plane of section P and advantageously perpendicular to the second transverse direction Y. 2).

The largest dimension DMAX is for example between 0.5 and 5 m.

The two parts 40A and 40B advantageously have, in the plane of section P, a cradle shape preferably comprising a substantially flat bottom 48, for example substantially perpendicular to the second transverse direction Y. The outer envelope 40 has, in the plane section P, two ends 50A, 50B opposite in the transverse direction X and preferably substantially semi-circular.

The portions 40A and 40B are adapted to be brought closer to each other along the second transverse direction Y so as to form the outer envelope 40.

The stiffening structure 30 is for example a hollow tube. The stiffening structures 30 of the consecutive sections 28 are fixed to one another by means of the connectors 44 so as to ensure adequate rigidity to the device 15. According to a variant not shown, the stiffening structures 30 are simply welded together. to others.

The stiffening structure 30 is advantageously substantially parallel to the longitudinal direction Z.

The stiffening structure 30 of each section 28 is for example located approximately at the center of the section of the outer casing 40 along the section plane P.

For example, all the transport ducts of the sections 28 are substantially parallel to the longitudinal direction Z.

The transport pipes 32A, 32B are for example suitable for raising petroleum product from the seabed 5. The transport pipes 32A, 32B are for example located on either side of the stiffening structure 30 in the direction transverse X.

The transport pipes 34A, 34B are for example suitable for the injection of water into the seabed 5. The transport pipes 34A, 34B are for example located on either side of the stiffening structure 30 in the direction transverse X, and are farther from the stiffening structure than, respectively, the transport pipes 32A, 32B.

The transport pipe 36 is for example intended for the rise of gas from the seabed 5 to the collecting structure 10. The transport pipe 36 is for example located between the transport pipes 32B and 34B in the transverse direction X.

Thus, in the example shown, the transport pipes 34A, 32A, the stiffening structure 30, the transport pipes 32B, 36 and 34B are aligned in this order in the section plane P in the transverse direction X.

The stiffening structure 30 and the transport lines 32A 32B, 34A, 34B, 36 are substantially parallel to an alignment plane P "and are traversed by this alignment plane.

In the example shown, the alignment plane P "and the median plane P 'are merged.

The transport pipes 38A, 38B are for example intended to allow the injection of gas in some of the other transport pipes. In the example shown, the transport pipes 38A, 38B are not aligned with the other transport pipes, but are shifted in the second transverse direction Y with respect to the latter. The outer casing 40 optionally further comprises spacers (not shown) extending between the portions 40A, 40B and the stiffening structure 30 or the transport ducts, so as to define locations for the stiffening structure or ducts. transport, as will appear below.

A method of assembling and constructing the device will now be described with reference to FIGS. 3 to 10.

The method implements, for example, a floating structure 100 (FIG. 3). The structure 100 includes an assembly ramp 102 for assembling the sections 28, and storage areas 104, 106 and 108 respectively adapted to store the half-shells 46, the stiffening structures 30 and the transport pipes.

The structure 100 is advantageously modular, that is to say that it comprises modules that define the storage areas 104, 106 and 108, for example as shown in FIG.

The floating structure 100 advantageously further comprises a crane 110.

As can be seen in FIG. 3, the assembly ramp 102 is situated partly on a platform 112 of the floating structure 100, and partly on the outside of the platform so as to serve as a guide for the sections 28 already assembled and gradually launched, as will be explained below.

The method is advantageously iterative.

It should be noted that in FIGS. 4 to 10, the orientation directions are denoted X ', Y' and Z 'and correspond to the directions X, Y and Z of FIG. 1, except that the longitudinal direction Z 'is not substantially vertical as when the device 15 installed, but for example substantially horizontal.

In a first step shown in FIG. 4, on the assembly ramp 102, a first section 28A of the future device 15 is obtained, the first section 28A already being assembled. There is also obtained a second section 28B partially assembled and mechanically connected to the first section 28A already assembled. The second portion 28B partially assembled comprises one of the two parts 40A, 40B of the outer casing 40, said portion being in the longitudinal extension of the first section 28A and receiving the stiffening structure 30 and the transport pipes of the second section connected mechanically at the first section 28A.

In a second step, the portion 40A of the outer envelope 40 is provided, the stiffening structure 30 and the transport pipes of a third section 28C intended to be mechanically connected to the second portion 28B partially assembled. Part 40B of the outer casing 40 of the second partially assembled section 28B is also provided.

In a third step shown in FIG. 5, the portion 40A of the outer envelope of the third portion 28C is placed on the assembly ramp 102.

This portion 40A is placed in the longitudinal extension of the second portion 28B partially assembled and is adapted to form a receptacle of the stiffening structure 30 and transport pipes of the third section 28C.

As shown in FIG. 5, the stiffening structure 30 of the third section 28C is placed in the portion 40A of the outer envelope 40 of the third section 28C. The rigidification structure 30 which has just been installed with the stiffening structure 30 of the second portion 28B partially assembled is mechanically connected. We are then in the state shown in FIG.

As shown in FIG. 7, the transport lines of the third section 28C are also installed and connected respectively to the transport pipes of the second section 28B. This connection is advantageously made by raising the transport pipes of the second section 28B, as shown in FIG. 7. This is made possible by the fact that the second partially assembled section 28B is located in a free part of the assembly ramp 102. and has not yet been pushed into the part of the assembly ramp where the first section 28A is located in FIG.

Furthermore, the connection of the stiffening structure 30 and the transport pipes of the third section 28C respectively with the stiffening structure and the transport pipes of the second section 28B may a priori be carried out in any order. At this stage, one is in the state shown in Figure 8, wherein the two sections 28B and 28C are partially assembled and mechanically connected to each other.

Then, as shown in FIG. 9, the part 40B of the outer casing 40 of the second section 28B is fixed on the part 40A already present, for example using the straps 42 as shown in FIG. 10. At this stage , a second section 28B newly assembled and similar to the first section 28A already assembled is obtained.

It is then possible to push longitudinally with respect to the ramp 102 the first section 28A already assembled, the second section 28B newly assembled and the third portion 28C partially assembled. We then find ourselves again in the initial configuration shown in Figure 4, the newly assembled section 28B playing the role of the former first section 28A already assembled.

The method can thus be iterated as many times as necessary to add additional sections 28.

The sections 28 thus produced and connected are then towed to the site of their installation to obtain the device 15.

According to another variant not shown, the assembly ramp 102 is located on the ground and not on a floating structure such as the structure 100.

Thanks to the characteristics described above, the device 15 is easy to assemble from inexpensive elements. This reduces the cost of the construction of the device 15. In addition, the oblong shape of the outer casing 40 gives the device 15 an acceptable hydrodynamic behavior. The sections are easy to assemble and connect on an assembly ramp. In particular, the cradle shape of the portions 40A, 40B of the outer casing makes it possible to easily install the stiffening structure 30 and the transport ducts, and then to close the outer casing 40.

Claims (9)

1Dispositif (15) for forming a riser for transporting petroleum products from a seabed (5) to a collector structure (10), or vice versa, the device (15) comprising a plurality of mechanically connected sections (28) and successively to each other in a longitudinal direction (Z), each section (28) comprising: - optionally a reinforcing structure (30) of the riser, - at least two, preferably at least three, transport ducts ( 32A, 32B, 34A, 34B), and - an outer envelope (40) having at least two parts (40A, 40B) fixed to one another so as to surround the transport lines (32A, 32B, 34A, 34B) about the longitudinal direction (Z), the outer envelope (40) having a section along a cutting plane (P) perpendicular to the longitudinal direction (Z), said section being oblong. 2. - Device (15) according to claim 1, wherein the sections (28) are substantially similar to each other. 3. -Dispositif (15) according to claim 1 or 2, wherein said section of the outer casing (40) has a larger dimension (DMAX) in a transverse direction (X) perpendicular to the longitudinal direction (Z), and a width (DMIN) in a second transverse direction (Y) perpendicular to the longitudinal direction (Z) and the transverse direction (X), the largest dimension (DMAX) being greater than or equal to 1.3 times the width ( DMIN), preferably 1.5 times the width (DMIN). 4. - Device (15) according to any one of claims 1 to 3, wherein the two parts (40A, 40B) of the outer casing (40) are substantially symmetrical to each other with respect to a median plane (P ') perpendicular to the plane of section (P). 5. - Device (15) according to any one of claims 1 to 4, wherein at least one of the two parts (40A, 40B) of the outer casing (40) has in the plane of section (P ), a cradle shape preferably having a substantially flat bottom (48). 6. -Dispositif (15) according to any one of claims 1 to 5, wherein the outer casing (40) has, in the cutting plane (P), two ends (50A, 50B) opposite in a transverse direction (X) perpendicular to the longitudinal direction (Z), each of the two ends (50A, 50B) being preferably substantially semicircular. 7. - Device (15) according to any one of claims 1 to 6, wherein, for each of the sections (28), the transport pipes (32A, 32B, 34A, 34B) are substantially parallel to a plane of alignment (P "), and are traversed by the alignment plane (P"). 8. - Method of construction and installation of a device (15) according to any one of claims 1 to 7, comprising the following steps: - on an assembly ramp (102), obtaining a first section (28A) of the device (15), the first section (28A) being already assembled, and obtaining a second portion (28B) partially assembled and mechanically connected to the first section (28A), the second section (28B) partially assembled comprising one (40A) of the two parts (40A, 40B) of the outer casing (40), said part being in the longitudinal extension of the first section (28A) and receiving the transport pipes of the second section (28B) connected mechanically at the first section (28A), - supplying one (40A) of the two parts (40A, 40B) of the outer shell (40), optionally supplying the stiffening structure (30), and supplying the transport pipes (32A, 32B, 34A, 34B) of a tro isth portion (28C) to be mechanically connected to the second section (28B), - establishment of said (40A) of the two parts (40A, 40B) of the outer casing (40) of the third section (28C) on the assembly ramp (102), said part (40A) being placed in the longitudinal extension of the second section (28B) partially assembled and being adapted to form a receptacle of the transport pipes (32A, 32B, 34A, 34B) of the third section (28C), - placing the transport pipes (32A, 32B, 34A, 34B) of the third section (28C) in said portion (40A), and putting into mechanical connection the transport pipes (32A, 32B, 34A, 34B) of the third section (28C), respectively with the transport pipes (32A, 32B, 34A, 34B) of the second section (28B) partially assembled to obtain a third section (28C) partially assembled, - supply of the other ( 40B) of the two parts (40A, 40B) of the envelope external pe of the second portion (28B) partially assembled, and - fixing the other (40B) of the two parts (40A, 40B) on one (40A) of the two parts (40A, 40B) of the outer envelope ( 40) of the second section (28B) partially assembled to obtain a second section (28B) newly assembled. 9. - Method according to claim 8, wherein the assembly ramp (102) is located on a floating structure (10), the method further comprising the step of pushing longitudinally with respect to the assembly ramp the first section (28) already assembled, the second section (28B) newly assembled and the