Smart Compensator

The present invention regards a protection system for protecting a fluid operated element, preferably an element within a removable plug for sealing off a pipeline. The element may be a fluid operated valve device, transponder, fluid operated cylinder etc.

When using a removable plug within a pipeline for temporarily sealing off the pipeline one needs a control system which makes it possible to release the plug when one wants to and in response to events in and around the plug, for instance increase or decrease of the fluid pressure in the fluid in the pipeline, which makes it necessary to release the plug.

A plug may comprise at least one fluid operated cylinder, i.e. a chamber with a movable barrier, i.e. a piston movable within the chamber, moved by fluid pressure, for operating gripping and or sealing means of the plug. The gripping and sealing means are activated to set the plug at the desired location, by gripping the internal wall of the pipeline to fixate the plug and seal off the pipeline preventing fluid in the pipeline from moving from one side to the other side of the plug when the plug is set.

This fluid operated cylinder must in the case of an event, have arrangement or a control system making it possible to release any pressurized fluid within the cylinder to make it possible to free the gripping and sealing means. Usually there is arranged a dump valve in connection with the fluid chamber. The dump valve would be operated either directly or by a control valve in response to a pressure of the fluid in the pipeline. The pressure of the fluid in the pipeline may be actively pressurized to operate the valve or there may be a fault somewhere raising the need to free the plug. A plug similar to this is for instance described in the applicants own patent application No 20023100.

Having the dump valve and or the control valve directly operated by the fluid in the pipeline will lead to a contamination and possible failure of the dump and or control valve. There are always impurities in the pipeline fluid, and the plug may be used in a pipeline with any kind of fluid, gas, oil, mixtures of these, water, chemicals etc. which all have different properties than a standard hydraulic oil normally used to operate a valve. When having these vales or other equipment in the plug directly operated by the pipeline fluid, the fluid lines leading to the valves, the valves and related equipment have to be cleaned each time the plug has been used. This is a time consuming and costly operation. For removable plugs that are used several times in different environments, this means a costly procedure.

It is an aim with the present invention to protect vital elements operated by a pressure in an external fluid, for instance in a plug, from contamination by the

external fluid. It is also an aim with the present invention to provide a protection system for elements, as for instance a valve device, in relation with plugs which needs less maintenance, and is easier to clean. It is also an aim to provide a system for use in relation to a plug that is more reliable with less contamination of vital parts of the control system and thereby less likely to fail.

These aims have been met by a protection system as defined in the following claims.

The protection system for protecting elements operated by a pressure in an external fluid has in a control fluid connection to an external fluid a barrier system. The control fluid connection is there for directly reading the fluid pressure in the external fluid for operating the element, for instance a valve device. This control fluid connection may for instance be a pipe, a tube or a bore in the casing of a part of the plug or related equipment, as for instance a control module attached to the plug, with an open end to the external fluid, or other combination making it possible to transfer the external fluid pressure to the elements to be operated by the external fluid pressure. The external fluid is, in the case of the protection device being used in a plug, the fluid within the pipeline, wherein the plug is used. The open end of the control fluid connection may be arranged to read the pressure at the low pressure or high pressure side of the plug or as an alternative arranged to read both sides of the plug.

According to the invention there is in the control fluid connection positioned a barrier system. The barrier system comprises a movable barrier and an internal fluid within the control fluid connection between the movable barrier and the fluid operated element to be protected, as may for instance be a valve device, preventing external fluid from contact with the fluid operated element. The movable barrier may be a piston (double or single rodded or with no rod), flexible membrane or just a division between the external fluid and the internal fluid, where there are non- mixing of the fluids, which may be achieved by large variation in density of the fluids. The internal fluid between the movable barrier and the element to be protected may preferably be a fluid normally used to operate the element. The element to be protected is an element operated by a fluid pressure, for instance valves, transmitters, fluid cylinders etc.

In an embodiment where the element to be protected is a valve device in relation with a plug, the valve device comprises a dump valve for at least one fluid operated cylinder. The fluid operated cylinder may be operating gripping and or sealing means of the plug, and the external fluid will be the fluid within the pipeline, wherein the plug is used. The fluid operated cylinder may be a liquid or gas operated cylinder. It may be only a piston, a single or double rodded piston fluid operated cylinder. It may be arranged within the centre of the plug, within a

connected control module or in different ways within the plug. There may be one or several fluid operated cylinders for operating the gripping and sealing means, separately or together. The dump valve may be in connection with one or both sides of the piston in the fluid operated cylinder, or one may have one dump valve for each side of the piston. The valve device may be arranged within, partly within or even outside the plug and or in a control module connected to or even within the plug. The dump valve may be connected to one fluid operated cylinder or several fluid operated cylinders.

In one embodiment the protection system may protect at least one control valve with a barrier system in the control fluid connection between the control valve and the external pipeline fluid, which control valve actuates the dump valve for the fluid operated cylinder. The control valve may operate the dump valve with the internal fluid within the protection system, or have a mechanical or electrical operation of the dump valve as a response to pressures of the external fluid. In another embodiment the protection system comprises a barrier system in a control fluid connection between the dump valve for the fluid operated cylinder and the external pipeline fluid. In a third embodiment the protection system comprises a barrier system between a control valve and the external fluid as well a barrier system between the dump valve and the external fluid. This gives a double security in being able to release the dump valve in response to the pressure of the external fluid.

In the preferred embodiment the barrier system with the movable barrier comprises a chamber with a piston, with external fluid on one side of the piston and the internal fluid on the other side of the piston acting on the element to be protected as a dump valve and or a control valve.

The barrier system with the movable barrier may in a preferred embodiment also comprise a fuse device responsive to the fluid pressures of the fluids on either sides of the movable barrier, i.e. the piston. The fuse device may comprise of several fuse elements or be a common fuse element responsive to the fluid pressure on either sides of the movable barrier, i.e. the fluid pressure in the internal or external fluid. The one or several fuse elements may be formed at least partly by a part of or connected to the movable barrier and or formed at least partly of the wall forming the chamber for the movable barrier of the barrier system or a combination of these.

According to on aspect of the invention the fuse device comprises a first fuse element in connection with the piston, set to brake if the pressure of the internal fluid exceeds a predetermined value and or a second fuse element in connection with the piston, set to brake if the pressure of internal fluid decreases below a predetermined value or one common fuse elements for these situations. There may

also be a separate fuse element or the same fuse element may also be responsive to predetermined values of the external fluid pressure.

In one embodiment the first fuse element is formed as a protruding part of the chamber wall with a smaller extension in the travelling direction of the piston than the rest of the chamber wall so that a part of the piston will move beyond the protruding part if pressure of internal fluid exceed a predetermined value and thereby brake the barrier function of the piston, and the second fuse element comprises a stopper element connected to the piston and interacting with a part of the internal wall of the chamber, for instance the protruding part, which stopper element will brake if internal pressure decreases below a predetermined value and thereby allowing external fluid to flow beyond the movable barrier or internal fluid beyond the movable barrier i.e. the piston.

In a second embodiment the first fuse element is formed as a through going part of the piston with a sealing element between the fuse part of the piston and the rest of the piston, where if the internal fluid pressure exceeds a predetermined value, the friction between the sealing element and the fuse part of the piston will not hold the elements together as the piston abuts against a part of the wall of the chamber, and a second fuse element formed as a stopper element connected to the fuse part of the piston and the rest of the piston, which stopper element will brake as the piston is abutting against another part of the chamber wall and if internal pressure decreases below a predetermined value. This arrangement may be formed centrally in the piston or in an off centre location of the piston. The chamber of the barrier system is also formed in such a manner that the barrier element or parts of it never will close the openings towards the external and internal fluids in the chamber. By this one gets a control system which is easier to clean when the plug is removed from the set location and should be used next time, by only having to clean the elements of the protection system and not the elements to be protected. This gives a more cost effective removable plug. There is also less possibility of the control system for a dump valve to fail since there are less possibilities of getting impurities within the vital elements of the control element.

The invention will now be explained with embodiments of the invention and with reference to the accompanying drawings where:

Fig. 1 show schematically a first embodiment of a protection system according to the invention, Fig. 2 shows schematically a second embodiment of a protection system with alternative configurations,

Fig. 3 shows an embodiments of a barrier system according to the invention and

Fig. 4 a-g shows several schematic embodiments of a protection system positioned in relation to a schematic plug within a pipeline.

In fig. 1 there is shown a protection system where the element in this embodiment is a valve device comprising a dump valve 7 connected to a hydraulic cylinder 5 by fluid lines 21, 22 to both sides of the hydraulic cylinder 5. The hydraulic cylinder 5 is as schematically indicated, arranged within a plug 2. The dump valve 7 may have at least two different activation systems which will be explained below.

The first system comprises of a control fluid connection 9c in communication with a source of external fluid. The control fluid connection 9c comprises an interior fluid line 13' between the dump valve 7 and a barrier system 10 with an internal movable barrier 11, the barrier system 10 and an external fluid line 12 between the barrier system 10 and the external fluid. This gives communication between an external fluid and the dump valve 7.

A change in the external fluid acts through the external fluid line 12 on the movable barrier 11 within the barrier system 10. The movable barrier 11 transfers the pressure to the internal fluid within the barrier system 10 and the internal fluid line 13' which acts on the dump valve 7.

The second system or activation mode comprises a control connection 20 between the dump valve 7 and a control valve 8. From the control valve 8 there is a control fluid connection 9a to the external fluid. The control fluid line 9a comprises of an internal fluid line 13 between the control valve 8 and the barrier system 10, which is the same barrier system 10 as in the first activation module with the movable barrier 11, with the external fluid line 12 from the barrier system 10 to the external fluid. The pressure in the external fluid will be transferred to the internal fluid which acts on the control valve 8, which thereafter will act on the dump valve 7.

The dump valve 7, control valve 8 and barrier system 10 can as indicated in this example be arranged within a control module 6, which may be separate, but connected to the plug or positioned within the plug.

The dump valve 7 may have several operational modes when activated by a pressure change in the external fluid. The fluid within the hydraulic cylinder 5 may be allowed to flow from one side of a piston to the other side of the piston, preferably in the case of a double rodded piston, as indicated in fig. 1. The fluid may be allowed to flow out of the hydraulic cylinder to a void specially designed for this within the control module or let out of the dump valve and or control module through an external dump line 23. The external dump line 23 may lead to internal voids within the plug. In one possible embodiment the excessive fluid within the fluid cylinder may be lead through line 9c, out and into the barrier system 10 and dump valve 7.

Another embodiment is shown in fig. 2. The difference is that there are two barrier systems 10 and 10', one for operating the control valve 8 and one for operating the dump valve 7 directly. The control valve 8 is connected to an internal fluid line 13' connected to a barrier system 10' with a movable barrier 11'. This barrier system 10' is in connection with the external fluid through the external fluid line 12'.

There is in fig. 2 with dotted lines indicated two different configurations of the control system with a protection system according to the invention. In one configuration all the elements, barrier systems 10,10', control valve 8 and dump valve 7 may all be arranged within the plug as indicated with dotted line 2'. In another configuration the control valve and associated barrier system 10' may be arranged within a control module marked with dotted line 6' and the other elements within the plug as indicated by dotted line 2".

The arrangements of the different elements may be done in several ways, as further explained and shown in relation to the description of fig. 4a-g. A barrier system according to the invention may have several configurations. One possible embodiment is shown in Fig. 3. The figure show a sketched cross section of half of a barrier system, with a centre line a. The barrier system 10 comprises of a movable barrier 11 positioned within a chamber formed within a house or housing 14. The movable barrier 11 divides the camber in an external fluid chamber 15 and an internal fluid chamber 16. The movable barrier is arranged with a sealing element 17 between the barrier 11 and a wall of the housing 14. The internal fluid chamber 16 is in fluid communication with the rest of a control fluid connection through line 13. The external fluid chamber 15 is in connection with an external fluid source through an opening 12 in the wall of the housing 14. The barrier system also comprises fuse systems. The first fuse system comprises of a first fuse element 18 arranged centrally within and forms a part of the movable barrier 11. The first fuse element 18 runs all the way through the movable barrier 11, and is arranged with a sealing element 17 in the facing surfaces of the moveable barrier 11 and the first fuse element 18, the sealing element 17 forms a friction force between the fuse element 18 end the barrier 11. There is also a second fuse system comprising of a second fuse element 19 arranged centrally on the movable barrier. These fuse systems cooperates with protrusions in the walls of the housing 14. The walls of the housing are also formed in such a manner that parts of the movable barrier or associated elements never may close the opening to the external fluid source or the opening to fluid line 13.

This gives that if there is a larger pressure difference across the movable barrier, than a predetermined allowable pressure difference, the fuse elements will brake the barrier function of the barrier element. This may be caused by a pressure increase or a pressure drop in the internal or external fluid. The form of the internal fluid

chamber and the fuse elements will cause a breakage of the sealed separation of the internal fluid chamber and the external fluid chamber allowing fluid to flow from one of the chamber to the other. There may be other possible arrangements for fuse systems in relation to the movable barrier and the separation of the internal and external fluids.

Fig. 4a-g shows different configurations of the invention in relation to a plug or plug train arranged within a pipeline. As shown in fig. 4a, the invention is preferably arranged in connection with a removable plug 2, comprising sealing means 3, in the form of a packer and gripping means 4, which in the shown example is formed by slips movable on a coned member. A fluid cylinder arrangement (not shown) is arranged within the plug to operate the sealing and griping means. The plug is further connected to a control module 6 for controlling the operation of the plug 2. The control module 6 is in this embodiment arranged on a high pressure side of the plug when the plug is in an activated sealing mode. The plug is in the figure shown in an unset position within a pipeline 1.

According to the invention there the protection system according to the invention is shown in connection with as indicated a dump valve 7, which is in contact with a barrier system 1OA, which again is in contact with the external fluid through a line 12A open to the fluid at the, in the figures left side, of the control module, i.e the high pressure side of the plug. The control valve 8 for controlling the dump valve 7 is connected to a barrier system 1 OB, which is in contact with external fluid through line 12B, open to the external fluid at a position close to the sealing device 3 of the plug, i.e. in this embodiment the external fluid which is situated between the control module 6 and the plug 2. The invention may also be employed in connection with a plug train as indicated in fig. 4b. Where there are two plugs 2 and T arranged directly behind each within the pipe 1. There are two control modules 6 and 6', one on each sides of the two plugs 2,2', i.e. one on the high pressure side of the two plugs and one on the low pressure side of the two plugs. There is indicated on barrier system 10 with connection to the external fluid through line 12, which is open to the fluid at the high pressure side of the plug train.

Fig. 4c, shows a similar plug train to what is shown in fig. 4b. In this embodiment the barrier system 10 is in connection with the external fluid through fluid line 12 which in this embodiment is open to the external fluid situated between the two plugs 2,2' in the plug train.

In the embodiment 4d, the fluid line 12 is open to the external fluid at the low pressure side of the plug train, i.e. the fluid situated between the low pressure side plug 2' and its control module 6'.

In fig. 4e one has barrier system units 1OA and 1OB arranged for a plug train with two plugs 2,2' similar to fig. 4b. One barrier system 1OA is arranged in connection with the dump valve 7 and in communication with the external fluid through fluid line 12 open to fluid at the high pressure side of full plug train. The other barrier system 1OB, with contact to the external fluid through fluid line 12B at the same area as the first barrier system, is in contact with a control valve 8.

In fig. 4f, the dump valve 7 with barrier system 1 OA is in connection with external fluid at the high pressure side of the plug train. The control valve 8 barrier system 1OB is in contact with external fluid situated between the two plugs 2,2' in the plug train.

In fig. 4g the control valve 8 with barrier system 1 OB is in contact with exteήial fluid situated at the low pressure side of the two plugs 2,2' in the plug train, more precisely fluid situated between the low pressure plug 2' and the control module 6' on the low pressure side of the plug train. These figures are only examples of configuration and other configurations are of course possible, the dump valve and control valve may be positioned on the low pressure side control module, separate control modules or even in the plugs. There may be several dump valves, control valves, one control valve for each dump valve or one control valve operating several dump valves, one control valve may also be connected to external fluid at several locations etc. A skilled person will understand this.

The invention has now been explained with different embodiments of the different elements of the invention. There may be envisages alterations and modifications to the explained embodiments that are within the reach of a skilled person and still within the scope of the invention as defined in the following claims.

The dump valve may also in one embodiment, where the hydraulic cylinder is relieved of pressure after the plug is set, have a configuration which when it is activated prevent the build up of pressure on either sides of the piston in the hydraulic cylinder, during for instance a release procedure of the plug. The hydraulic cylinder may be a gas operated cylinder. The system according to the invention may be all together positioned within a plug, without an additional connected control module, i.e. the control module may be formed within the plug. The plug may also be a remotely or an umbilical line operated plug. The protection device is described to prevent external fluid from penetrating into vital element within the plug, one may of course also use the protection device to prevent internal fluid from penetrating out of the plug and into the external fluid.