GB2197705A

GB2197705A - Transportation conduit

Info

Publication number: GB2197705A
Application number: GB08726074A
Authority: GB
Inventors: Magne Grosvik; Kjell Ronningen
Original assignee: Aker Engineering AS; Standard Telefon OG Kabelfabrik AS
Current assignee: Aker Engineering AS; Nexans Norway AS
Priority date: 1986-11-07
Filing date: 1987-11-06
Publication date: 1988-05-25
Anticipated expiration: 2007-11-06
Also published as: NO864468D0; GB2197705B; GB8726074D0

Abstract

A conduit comprises an inner pipe (21) for transmission of gas and/or oil and a plurality of elements (23) provided as a layer outside the pipe (21) and being adapted for transmission of power, e.g. electric power or hydraulic power. The elements (23) at least some of which may be of copper are insulated against the outer environment, by thermal insulation material (24). The inner pipe (21) can be manufactured from steel and can be surrounded by a corrosion-preventing layer (22). Three of the elements (e.g. 26, 27, 28) are used for the transmission of 3-phase A. C. whilst two of the elements (e.g. 36, 37 Fig. 3 not shown) in another embodiment may be used for transmission of D. C. <IMAGE>

Description

Transportation Conduit The present invention relates to a transportation conduit adapted for transporting material between two installations.

The invention is especially contemplated for use in connection with transportation pipes or conduits adapted for installation on the sea bed between a stationary or floating off-shore platform and an onshore terminal. However, it is to be understood that the principle of the invention can also be used in connection with on-shore systems, or for transportation between sea bed installations or from the sea bed to a platform.

In connection with off-shore production plants, for instance for the production of gas and/or oil, a portion of the gas might be transported ashore via transportation tubes, whilst simultaneously electric power which is generated by another portion of the gas is transmitted in separate electric cables which preferably run in parallel to the sea bed transportation tubes.

The object of the invention is to provide a combined transportation conduit which can be installed simply and which can also be manufactured at a lower cost than separate pipes and cables.

According to the invention there is provided a conduit adapted for transporting material between two installations, comprising a pipe for transportation of gas and/or oil or similar, and a plurality of elements arranged along the outside of the pipe, for the transmission of energy, e.g. electric power and/or electric signals, along the conduit.

In other words the invention provides an expanded transportation conduit to be used not only for the transportation of oil or gas or other material, but also for parallel transportation of other forms of energy, e.g. electric power.

The pipe can be covered by an inner layer of corrosion-inhibiting material, outside which said elements (preferably in a layer) are provided, there being provided an outer thermal insulation layer around said elements. This embodiment gives a robust, combined transportation conduit which can tolerate being laid out on the sea bed between a stationary or floating offshore platform and an on-shore terminal.

The pipe might be manufactured from steel or a flexible material having a substantial strength, whereas the elements may be manufactured from copper or similar material, with high electrical conductivity, including an adequate electrical insulation therearound.

However, it is to be understood that elements can also include devices for transportation of energy other than electric energy, for example pipes for the transportation of hydraulic power.

In another embodiment of the invention the elements might include reinforcement means.

Embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawing, in which: Fig. 1 is a simplified block diagram illustrating how a combined transportation conduit according to the invention can be installed; and Fig.2 and 3 illustrate a first and a second embodiment of the present transportation conduit, respectively.

In Fig.1 a transportation conduit, which is designated by reference numeral 1, is installed between two distribution terminals 2 and 3. Gas and/or oil is transported by being transferred through a pipe from a first portion 4 to a second position 5, and elements (see Fig.2 and 3) of the transportation conduit can transfer for example electric and/or hydraulic signals from one or more further positions 6 at the first end of the conduit to one or more further positions 7 at the second end thereof. Some of the elements of the transportation conduit are adapted for transferring electric power from a current source 8 at the first end of the transportation conduit 1 to a consumer location 9 at the other end thereof. The transmission of the electric power between the distribution terminals 3 and the consumer location 9 is passed through a current measuring device 10.If the electric current should sink below a predetermined level because the consumption of current at the comsumer location is below normal, the device 10 might be so arranged that it will switch in an extra current load 11, such that the current throughput via the power conducting elements of the transportation conduit is kept between predetermined levels. In this way, the gas/oil pipe is maintained at a predetermined temperature.

In Fig. 2 and 3 there are illustrated simplified sections through embodiments of two combined transportation conduits 20 and 30, respectively, said embodiments according to the present invention being adapted for combined transportation of oil/gas and transmission of electrical power.

Each of the transportation conduits 20 and 30 comprises an inner pipe 21,31 for transportation of gas and/or oil or similar, said pipe being manufactured from steel or a flexible material of substantial strength. Outside the inner pipes 21 and 31, respectively, there is provided a layer of corrosionpreventing material 22 and 32, respectively, if the pipe in itself is not sufficiently protected against corrosion. Outside the pipe 21, 31 there is provided a layer of elements 23 and 33, respectively, each of which might be manufactured from copper or some other material having excellent electric conductive properties and being sufficiently electrically insulated.The elements of the layer 23, 33 might be used for transmission of direct current or alternating current, depending on the conditions prevailing on the production location and the transmission requirements to the consumer location.

The conduit 20 of Fig.2 is adapted for 3-phase alternating current, whereas the conduit of Fig.3 is adapted for transmission of direct current.

Appropriately, three elements 26,27,28 on each pipe 20 may be used for the transmission of 3-phase alternating current, as shown in Fig.2. The elements should then preferably be evenly distributed around the circumference of the pipe at an angular separation of 1200C. A multiple of 3 elements might also be used, in which case the elements should be installed in such a manner that the current is distributed evenly round the circumference.

When a transmission of direct current is contemplated, two conductors 36, 37 representing the forward and return conductors, respectively, or a multiple of two conductors, may be distributed in the layer 33, as depicted in Fig.3. Alternatively, one or more of the elements of the layer 34 might be used for the transmission of direct current in a first direction, whereas the return current might follow a path through the sea water or through a separate cable or another combined transportation conduit.

Some of the elements 25 or 35 in the layer 23, 33, respectively, can serve for the transmission of other forms of energy than electric energy, for example transmission of a hydraulic medium, possibly in combination with a transmission of electric signals and power. The elements 25, 35 can also be constituted by cables for the transmission of telecommunication signals.

Outside the layer of elements 23, 33, respectively, there is provided an outer insulation layer 24 and 34, respectively, serving to insulate the elements in said layer thermally from the surroundings.

The transportation conduit can if necessary be provided with an outer mechanical protection layer, which is not illustrated on the drawings.

It is to be understood that the current being conducted through the elements in the layer 23 and 33, respectively, can be used for heating the oil/gas being transported through the inner pipe 21 and 31, respectively, and will thus contribute to giving the oil/gas a favourable floating capacity and prevent condensation and sedimentation. For this purpose the inner layer 22, 32 and outer insulation layer 24,34 might be configured in such a manner that the heat emission from current-conducting elements 23 and 33, is directed substantially inwardly towards the medium to be transported in the inner pipe 21, 31. In other words the insulation 22 and 24 of conduit 21, and the insulation 32 and 34 of a conduit 31, should be adapted to the heat emission from the current conducting elements 23 and 33, respectively.

It should be noted that two or more conduits according to the invention can be arranged side by side, or in any appropriate configuration. As indicated above, for direct current transmission one of the conduits might be used as a forward path for the direct current, with another conduit for the return path. Correspondingly, when alternating current is contemplated, there might be used for example three conduits, each constituting a main conductor in a 3phase system, each element therein being distributed as explained above.

It should further be noted that at least some of the elements 25 in the conduit 20 illustrated in Fig.2, and at least some of the elements 35 in the conduit 30 illustrated in Fig.3, might constitute reinforcing elements contributing to the overall strength of the combined transportation conduit described above.

Finally, it is to be understood that the embodiments of the present invention described above are to be regarded as examples only and not to be considered as any limitation to the scope of the invention.

Claims

Claims:

1. Conduit adapted for transporting material between two installations, comprising a pipe for transportation of gas and/or oil or similar, and a plurality of elements arranged along the outside of the pipe, for the transmission of energy, e.g. electric power and/or electric signals, along the conduit.

2. Conduit as defined in claim 1, wherein the pipe is enclosed by an inner layer of corrosion inhibiting material outside which the transmission elements are provided.

3. Conduit as defined in claim 1 or 2, wherein an outer thermally insulating layer is provided around the transmission elements.

4. Conduit as defined in any preceding claim, wherein the pipe is manufactured from steel or a flexible material of great strength.

5. Conduit as defined in any preceding claim, wherein the transmission elements are made from copper or other material of high electrical conductivity, and are provided with sufficient electrical insulation.

6. Conduit as defined in any preceding claim, including at least one pair of electrical transmission elements for enabling the conduit to transport both oil/gas and direct current power, or at least one trio of electrical transmission elements for enabling the conduit to transport both oil/gas and 3-phase alternating current.

7. Conduit as defined in any preceding claim, wherein the plurality of transmission elements includes conductors for transmission of hydraulic energy.

8. Conduit as defined in any preceding claim and arranged between distribution terminals at least one of which comprises regulation equipment or measuring devices for electrical current.

9. Conduit as defined in claim 8, wherein the regulation equipment comprises at least one spare current load which can be switched in as necessary to maintain a defined electric current and heat emission to the contents of the transportation conduit.

10. Conduit as claimed in any preceding claim, wherein one or more elements constitute a reinforcing means contributing to the overall strength of the combined transportation conduit.

11. A combination of conduits as defined in any preceding claim, including two conduits for combined transportation of oil/gas and direct current power, or three conduits for combined transportation of oil/gas and 3-phase alternating current.

12. Conduit substantially as described hereinbefore with reference to Fig. 2 or Fig. 3 of the accompanying drawings.