GB2389884A

GB2389884A - Flow line securing support

Info

Publication number: GB2389884A
Application number: GB0214081A
Authority: GB
Inventors: Christian Huau
Original assignee: Schlumberger Holdings Ltd
Current assignee: Schlumberger Holdings Ltd
Priority date: 2002-06-19
Filing date: 2002-06-19
Publication date: 2003-12-24
Anticipated expiration: 2022-06-19
Also published as: GB2389884B; GB0214081D0

Abstract

A flow line support for securing a pipe which is deformable according to variations in the flow characteristics of the fluid carried by the pipe such that shocks in the pipe are damped. The support may comprise three deformation domains comprising; an elastic domain corresponding to small flow variations, a plastic domain corresponding to large flow variations and a limit domain corresponding to securing of the pipe in any flow variation case.

Description

FLOW LINE SECURING; SUPPORT

The invention relates to a flow line securing support and particularly to a flow line support aiming to maintain, in the safest way, pipelines in which fluids having 5 unstable flow characteristics are transferred.

After a hydrocarbon well has been drilled and made safe, production is immediately started from the well for evaluation purposes and it is at first necessary to install specific equipment that can identify the types and magnitudes of the various components of the fluids produced from the well, and estimate the production 10 capacities of the well. Later, other production equipment replaces this testing equipment. Nevertheless, from the very beginning of the well production, it is necessary to connect all equipment to the well (and together) by mean of pipelines in which the effluent will be transferred.

These pipelines need to be secured to the ground and several techniques have been 15 previously proposed. In one, rigid supports are used that are more or less fixed to the ground. In another, the lines are laid on concrete blocks and secured by cables or by rigid supports.

However, at the early time of production and of well testing, the flow characteristics and the equipment behavior in new production conditions are not well known and 20 can lead to violent phenomena in the pipelines, generating hazardous motions of the lines. In such cases, the rigid supports previously proposed are neither adequate nor safe. In case of violent motions of the lines, such supports can be broken, leaving the line free to move dangerously, which can seriously injure workers in the vicinity of the line. Rigid supports can also transmit the energy down the fixations until 25 reaching a weak interface that will rupture.

It is thus an object of the invention to provide a new type of flow line securing support that is able to accommodate the effects of sudden changes in the flow characteristics of the effluent without occurring hazardous pipeline motions.

To this end, the invention provides a flow line support for securing a pipe wherein a 30 well effluent flows, said support comprising a first end connected to the pipe and a FR21.1051

second end connected to a base support, characterized in that said flow line support is deformable according to the variations in the flow characteristics of said effluent such that shocks in the pipe, due to said flow variations, are damped.

By this means, whatever the variations of the flow characteristics may be, and 5 consequently whatever the motions of the pipe may be, the support according to the invention will be deformed and thus the motions of the pipe will be damped, avoiding any accident for the persons who are working next to said pipe.

In a preferred embodiment of the invention, the securing support of the invention comprises several deformation domains corresponding to increasing variations 10 possibilities in the flow characteristics of the effluent. In particular, said support comprises three deformation domains comprising: - an elastic domain corresponding to small flow variations; a plastic domain corresponding to large flow variations; and - a limit domain corresponding to securing of the pipe in any flow 15 variation case.

Thanks to these requirements, the flow line support according to the invention is very practical to use. Actually, the fact that the flow line support is deformed only in a proportion relative to the forces it faces, enables to keep said support from breaking whatever the shocks in the pipe may be. For the smallest and usual 20 variations, i.e. most of the time in the elastic domain, the support according to the invention will stay perfectly unchanged. This will not be the case with rigid line supports in the state of the art that will mostly break in the range of forces corresponding to the plastic domain of the securing support of the invention.

In another preferred embodiment of the invention, the flow line support is 25 deformable in a preferred direction, said direction being in the same plane as the pipe motions.

This feature ensures that the deformable flow line support is placed in such a manner that any motion of the pipe is damped in the most efficient way.

Accordingly, the place of the flow line support and of the base support will be 30 dependent on the expected pipe motions.

FR2t.105t

! Another object of the invention is to provide a wellsite system comprising surface production and/or testing equipment connected together and to the well by mean of pipelines wherein the well effluent flows, said pipelines been secured to a base support by mean of at least one flow line securing support. According to said wellsite 5 system, the flow line securing support is deformable according to the variations in the flow characteristics of said effluent such that shocks in the pipelines, due to said flow variations, are damped.

Additional objects and advantages of the invention will become apparent to those skilled in the art upon reference to the detailed description taken in conjunction with

10 the provided figures: - Figure I is a schematic view of the strain/force curve specification

required for the flow line support; - Figure 2 is a schematic view of a flow line support according to the invention; 15 - Figure 3 is an example of a traction and compression characteristic curve obtained with a 11 Omm length support as represented on figure 2.

As it can be seen on figure I, the aim of the first development process of the support of the invention was to define the specification for a support in order to withstand

and damp violent motions of a pipeline. Typically, in order to provide a support that 20 fulfill these requirements but does not need to be replaced after every usual movement of the line, three deformation domains have been defined: a small elastic domain for the 'day-to-day" line supporting (normal usage), in such domain, the support according to the invention remains totally unchanged after shocks due to flow variations.

25 - a large plastic domain to accept and damped large line motions. This domain is particularly important because most of the hazardous and sudden motions of the pipe may lie therein. Consequently its definition needs to take safety limits into account in order to avoid any accident.

- a strong limit domain to maintain the line in any case, the rupture point 30 of the support being defined to be far over any highest pipe motion risk.

FR21.1051

According to motions that can be encountered in real field conditions, these

domains have been chosen to withstand the following forces: e - elastic domain: from O to 2 tons, corresponding to the force applied by e the pipe on the support of the invention, due to variations of the effluent 5 flow. In this domain, the support of the invention must present an elastic deformation capacity up to 12 mm.

- plastic domain: from I to 10 tons, leading to a support deformation between SO and 150 mm.

- strong limit domain: occurring when the force applied to the support can 10 be as important as 150 tons, leading to a maximum support deformation before reaching the rupture of said flow line support.

The objective is to provide a mechanical support having an elastic working range about O to 2 tons (10 to 20 kN) with a lOmm deformation, then a plastic working: range with about a 100 mm deformation for a traction/compression force until 10 15 tons ( 100 kN) and finally a high resistance range (before rupture) for a traction force up to 150 tons (1500 kN).

Figure 2 represents a schematic view of a flow line securing support addressing all the deformation domains that have been listed here above. Actually, this figure schematically represents a pipe I around which a collar 2 is secured, said collar 20 being attached to a base support 3 by means of a flow line support 5 according to the invention. A preferred implementation of the invention relates to a well site wherein pipelines are linked to production and/or testing devices and with each other, said pipelines being secured to base supports by means of flow line supports 5. 25 The base support 3 is preferably rigidly secured to the ground. However, depending on the places where the flow line support is used, the base support 3 may also be a "loose" base plate. Actually, said "loose" plate will be of particular relevance onshore or in the desert or muddy soil that offer very little mechanical resistance. In such conditions, the base plate can be either a re-usable heavy steel plate or a 30 concrete block.

FR21.1051

s Generally, the base support and the flow line support are secured in such a way that they lie in the same plane as the forecasted motions of the pipe due to the effluent flow variations.

Actually, a very cost-effective and easy way to realize a flow line securing support 5 according to the invention is to use a "slice" of a low yield strength pipe, as used in the oil industry, and making it work along one of its diameter, said diameter being in the same plane of the pipe motions.

In a non limitative embodiment of the invention, good results have been obtained with a ring having a length between 100 to 200 mm from a pipe with a thickness 10 between 6 and 8 mm and a 325 mm outside diameter. Two opposite holes have been drilled in the median plane of this ring in order to induce any deformation along one of its diameter. This feature is particularly interesting because by focusing any support deformation along a single direction, the motions of the pipe will be damped in the most significant way.

I S As it can be seen on figure 2, the support 5 is installed between the base support 3 and the collar 2 in such a manner that the axis of the two holes is vertical. This means that the support will damp the shocks in the pipe that will occur in a direction perpendicular to the pipe longitudinal axis. In an embodiment of the invention, a bolt fixes the ring, through its bottom hole, to the base support, and another bolt 20 located at 180 fixes the deformable support to the pipe clamp.

Figure 3 represents deformation values that have been obtained with an example of a support 5 having a length of 110 mm from a steel pipe as described here above.

This type of ring has showed very interesting characteristics related to strain/force requirements listed here above but the invention is not limited to that particular 25 support design (satisfying results have also been obtained for 160, 210 mm ring length). Figure 3 shows that this particular 110 mm ring has an elastic domain limited to a 10 kin traction/compression force leading to a maximum deformation of 10 mm.

Furthermore, the plastic domain of said support lies in a range of 10 kN to 35 kN for 30 a traction force and a flat force around 10 kN in compression. The needed energy to obtain a 100 mm deformation is around 2000 joules in traction and 1000 joules in FR21.1051

compression. After the compression test, it can be seen that traction forces have been applied to the same support. Finally, after most of the elongation, a force over 800 kin is needed for rupture, which is not represented on figure 3.

It thus appears that the example of support having the characteristics of the one of 5 figure 3 addresses all the issues raised by the variations of the flow in the pipe during any well testing and/or producing process. Moreover, this support being very cheap and easy to mount, it will be very simple to replace it any time one will decide that the deformations encountered have been important enough to decrease said support reliability and efficiency.

10 The support of the invention is not limited to the particular example that has been given but relates to any support that is capable of a deformation when being solicited by a pipe motion due to variation of the flow characteristics.

FR21.1051

Claims

- 1. Flow line support for securing a pipe (1) wherein a well emuent flows, said support (5) comprising a first end connected to the pipe and a second end 5 connected to a base support (3), characterized in that said flow line support is deformable according to the variations in the flow characteristics of said effluent such that shocks in the pipe ( I), due to said flow variations, are damped.
2. Flow line securing support according to claim 1, wherein said support (5) comprises several deformation domains corresponding to increasing variations l O possibilities in the flow characteristics of the effluent.
3. Flow line securing support according to claim 2, wherein said support comprises three deformation domains comprising: - an elastic domain corresponding to small flow variations; - a plastic domain corresponding to large flow variations; and 15 - a limit domain corresponding to securing of the pipe in any flow variation case.
4. Flow line securing support according to claim 3, wherein the elastic domain corresponds to a force applied by the pipe to said support (5), due to flow variations, comprised between O and 2 tons, leading to a possible elastic 20 deformation of said support up to 12 mm.
5. Flow line securing support according to claim 3 or 4, wherein the plastic domain corresponds to a force applied by the pipe to said support (5), due to sudden flow variations, comprised between I and 10 tons, leading to possible plastic deformation of said support up to 150 mm.

25
6. Flow line securing support according to any of claim 3 to 5, wherein the limit domain corresponds to a force applied by the pipe to said support (5) over 100 tons, which is over any possible shock due to flow variations.

FR2.1051

(
7. Flow line securing support according to any one of the preceding claims, wherein said support (5) is deformable in a preferred direction, said direction being in the same plane as the pipe (1) motions.
8. Flow line securing support according to claim 7, wherein said support (5) is a low 5 yield strength steel ring, deformable along one of its diameter.
9. Flow line securing support according to claim 8, wherein two opposite holes are drilled in the median plane of said ring, the first hole being connected to secured means fixed in a base support (3) and the second hole being connected to a pipe collar (2).
10 10. Flow line securing support according to claim 8 or 9, wherein said ring has an outside diameter of 325 mm, a thickness of 6 to 8 mm and a length from 100 to 200 mm.
11. Flow line securing support according to any one of the preceding claims, wherein the base support (3) comprises a re-usable heavy steel plate or a concrete block.

15
12. Wellsite system comprising surface production and/or testing equipment connected together and to the well by mean of pipelines wherein the well effluent flows, said pipelines been secured to a base support (3) by mean of at least one flow line securing support (S), characterized in that said flow line securing support is deformable according to the variations in the flow characteristics of 20 said effluent such that shocks in the pipelines, due to said flow variations, are damped.
13. Wellsite system according to claim 12, comprising a flow line securing support according to any one of claims 2 to I 1.

FR21.1051