PRESSURE CONTROL HEAD SYSTEM

The present invention regards a valve and a method for retrieving a cut elongated member after an emergency quick disconnect.

During a wire line intervention operation in a well a tool is lowered into the well at the end of a wire line. The wire line and tool is in normal operations introduced into the well with the aid of a lubricator attached to the wellhead. The tool will be positioned in the lubricator when the lubricator is lowered from the platform or vessel, performing the intervention. The wire line will be operated from the platform or the vessel to position the tool at the desired position in the well when the lubricator is attached to the wellhead and the tool is lowered into the well. The wire line will therefore extend from the tool through the lubricator and up to the platform or vessel performing the intervention.

When performing interventions the normal barriers in the well are opened and there are additional barriers in the lubricator, as for instance a pressure control head for controlling the pressure in the well when the normal barriers are opened. A pressure control head will often comprise seal sections in the form of flow tubes and or stuffing boxes arranged above a launching position for the tool to be introduced into the well. In case of emergencies quick disconnect normal procedure is to close a ram valve in the BOP and thereby cut the wire line to release it from the well. In normal operations today a cut wire line will be dropped into the well together with the attached tool string. This is an undesirable situation. To retrieve the cut wire line and the tool there must be initiated a costly fishing process which normally will involve the removing the wire line intervention equipment and a riser or rig must be installed on the wellhead in order to perform the fishing operation. There are several disadvantages associated with a fishing operation. One need additional equipment, there is a risk of damaging the X-mas tree and associated equipment, due to the weight of the riser and rig and the need for closely monitoring the position of these. There is also the risk of damaging downhole equipment and the tool string when it is dropped into the well. There is therefore a need for a method and wire line intervention equipment where some of these disadvantages are limited and possibly removed.

An aim with the present invention is to provide a method and pressure control head system for intervention work in a well and a valve for use in a pressure control head system where some of these disadvantages are limited and possibly removed. This aim is achieved with a method, a system and a valve according to the attached independent claims.

According to the invention there is provided a pressure control head system for intervention operations in a well. The intervention work might be done with for

instance a wire line, a cable or a coiled tubing. The pressure control head system has a cutting device for cutting an elongated member extending at least into the system. The elongated member may extend through the system during normal operations. The cutting device may be rams, ball valves, gate valves and other cutting devices. The pressure control head also has a sealing section for sealing off a through going bore through the system. This sealing section may be arranged to seal off the pressure control head with an elongated member extending through the system, and might for instance be one or more stuffing boxes, flow tubes etc. According to the invention the cutting device is arranged relatively above or substantially on the same level as the sealing section when the system is in use.

According to one aspect of the invention the system may be provided with a cutting device comprising sealing means for sealing off the through going bore through the system. Such a solution will give the feature of a device which both cuts an elongated member extending through the device and then also seals off the bore where through the elongated member extended. Even in this configuration the cutting device may be arranged above the sealing means of the cutting device, and the sealing means may act as the sealing section as referred to above. These sealing means will be normal sealing means for instance in relation to possibly a ram and or valve and will therefore not be explained in further detail here. According to a further aspect the system may comprise a holding device operable between a retracted position, where the elongated element may move relative the holding device, to a locking position, where the elongated member is held by the holding device, which holding device is arranged below the cutting device when the system is in use. The holding device may in a retracted position still be in contact with the elongated member and seal around the elongated member for the well pressure but still allow the elongated member to move relative the holding device. In a locking position the elongated member is locked and will not move relative the holding device, and therefore not fall into the well then the elongated member is cut relatively above the holding device. The holding device is operable connected to the cutting device and thereby activated by the movement of the cutting device. The holding device according to the invention may be a stuffing box arranged within the pressure control head below and operable connected to the cutting device or it may be a specific holding assembly operable connected to the cutting device.

According to another aspect the holding device is retrievable. This gives that the elongated member can be retrieved by retrieving the holding device. The elongated member may according to the invention also be retrieved with a tool lowered into the pressure control head, where the tool will grab the length of the elongated member protruding upwards from the holding device. Another possibility is to have a tool retrieving at least a part of the holding device or the holding device and a part of the pressure control head.

According to the invention there is also provided a valve for use in a pressure control head. The valve is particularly for use in relation to subsea wire line intervention work, but might have other uses. The valve will favourably be used in relation to a lubricator used for wire line intervention operations, and more specifically in relation to a pressure control head of a lubricator. The valve has a valve housing with a main bore and a valve element arranged movable within the valve housing. The valve element comprises a movable closure element movable between a valve open position and a valve closed position. The closure element may comprise a bore which in an open position of the valve is inline with the main bore of the valve housing for thereby provide an open bore through the valve, another possibility is to form the valve housing and closure element such that the closure element is moved away from the main bore of the valve housing in an open state of the valve, while it in a closed state of the valve covers the main bore. The valve element further comprises cutting means for cutting an elongated member extending into the valve. This elongated member may be a wire line during intervention work in a well, but may also be other kinds of elongated members as a cable, a slick line, composite cable, coiled tubing etc. The cutting means may be the cutting device as mentioned in relation to the pressure control head system. According to the invention the valve further comprises a holding assembly operable connected to the movement of the closure element and operable from a retracted position, where the elongated element may move relative to the holding assembly, to a locking position, where the elongated element is held by the holding assembly. The holding assembly will in a fully open stated of the valve be in a retracted position. When the closure element is moved for a valve open position to a valve closed position the holding assembly is moved from a retracted position to a locking position. By this one achieves a valve which during a closing procedure of the valve will cut any elongated member extending through the valve, lock the elongated member in the holding assembly and close the valve fully. In a wire line intervention operation in a well this means that one may close a valve and thereby secure the well at the same time as the cut wire line and tool string is not dropped into the well, but locked by the holding assembly of the valve. The holding assembly may be the holding device as referred to in the pressure control system.

According to one aspect of the invention the closure member is connected to the holding assembly by one at least partly mechanical connection. In this aspect the movement of the closure element may by a fully mechanical connection influence the holding assembly to move as well. There may also be other connections between the closure element and the holding assembly as part mechanical part hydraulic or part mechanical part electric, where for instance the mechanical movement of the closure element will trigger an operation of the holding assembly which then might be moved by hydraulic or electrical equipment. The connection may also involve transfer of signals between the elements, giving that there may a

distance between the closure element and the holding assembly. The last may also be possible with a fully mechanical solution. This also represent features of the pressure control head system having the cutting device and holding device, where the cutting device is the closure element with cutting means and the holding device is the holding assembly.

According to one aspect the mechanical connection between the closure element and the holding assembly may comprise an actuation surface part of the closure element. This surface part may by the movement of the closure element, activate the holding assembly. In one embodiment the actuation surface part may be an angled part of a side surface of the closure element. One possibility of an angled surface is to have the surface part angled in relation to the movement direction of the closure element, by this one achieves that the movement of the closure element will act on another element, as a cam surface. The angled surface may be linear or curved or have different section, giving the desired movement of the holding assembly which is actuated by the movement of the closure element. It is here also possible to have a stepped actuation surface part of the closure element.

According to one aspect the closure element may be a gate element. The gate element will be moved in a direction transverse to the longitudinal axis of the main bore of the valve, for closing of the valve. In other aspects the closure element of the valve may be a ball element or a flap element.

In one aspect of the invention the holding assembly may comprise at least two holding members for interaction with the elongated member extending through the valve in an open state of the valve. These holding members are moved from a retracted position to a locking position in interaction with a possible elongated member and locking this elongated member after it is cut by the cutting means of the valve. There are several ways to achieve such a feature. According to one aspect of the invention the holding assembly may comprise a wedge ring, a base and at least two holding members. The wedge ring may be formed as a mainly cylindrical element with a through going bore. The wedge ring may be formed with an end surface in abutment against a side surface of the closure element. The end surface of the wedge ring will also be in contact with the actuation surface part of the closure element during closure of the valve and thereby also form part of the mechanical connection between the closure element and the holding assembly. Further the wedge ring may comprise an inner angled surface section. This inner angled surface section may be arranged within the through going bore, forming a tapered part of the inner bore. This tapered part may be positioned close to the opposite end surface of the wedge ring compared with the end surface in abutment against the actuation surface part of the closure element. This angled surface section of the wedge ring may be in abutment against at least two holding members comprising an angled activation surface. This angled activation surface will face outwards in a radial

direction. The holding members may further be arranged movable in the base between a first position out of contact with the member and a second position in a locking contact with the elongated member extending into the valve. The base will during the closing of the valve be fixed relative the outer housing of the valve. The base element may be formed by a general cylindrical part and a flange part at one end of the cylindrical shape, which flange part is extending outwards in a general radial direction from the cylindrical part. According to one aspect the holding members may be arranged movable in slits in the base element, which slits guide the wedge elements in their movement between a first retracted position and a second position. In the second position the wedge elements will lock the elongated member in a position. The slits may be formed as through going through the cylindrical part of the base. There may in addition also be guiding elements in the flange part, as for instance grooves, in connection with the slits for a more securely guidance of the holding members. Alternatively the holding assembly may comprise chocks for locking and holding of the elongated member, another possibility is to have balls or other elements arranged in guiding grooves which when activated will lock the elongated member from moving in one direction but allow movement in the opposite direction. Another possibility is to have a wedge element rotate to activate the holding assembly to a locking position around an elongated member or combinations of these. These alternatives also apply to the holding device as defined in relation to the pressure control head system.

According to another aspect of the invention the cutting means may comprise a cutting edge within the bore in the closure element. In another embodiment the cutting means may be formed by a cutting edge on an outer surface of the closure element.

When the valve is closed any wire line extending through the valve in an open position is cut and is held and locked by the holding assembly, and thereby prevented from being dropped into the well. According to an aspect of the invention the holding assembly may comprise a retrieving system. This gives the possibility of retrieving the holding assembly with the elongated member locked in the holding assembly to an operator on a vessel or platform in the case with a wire line intervention operation. By this the two parts of the cut wire may again be joined and the tool may be recovered without a normal fishing operation. Such a retrieval of the holding assembly may be achieved by providing the valve with the functionality that the closure element after closure of the valve, where the holding assembly is also moved to a locking position, may be moved to a position where the valve normally would be open if the holding assembly was not locked. By moving the closure element to a valve open position one may get access to the holding assembly through the main bore of the valve housing, and the holding assembly then comprises means for retrieving the whole of the holding assembly up through the

main bore of the valve. This activity is possible since the holding assembly comprises means that prevent the holding assembly from releasing the elongated member when the closure element of the valve is moved to a valve open position. Another possibility is to retrieve the whole valve with the holding assembly. Yet another possibility is to use tools to connect to the part of the elongated member locked in the holding assembly and thereby retrieve the cut elongated member. A possibility if the holding assembly locks the elongated member from moving in one direction but allow it to move in another direction, alternatively that the holding assembly when the tool has grab of the elongated member is activated to a retracted position and thereby releases the cut elongated member so that it may be retrieved to the operator.

According to the invention there is also provided a method for retrieving a cut elongated member, as for instance a wire line in a well after an emergency quick disconnect or at least a part of the emergency quick disconnect where the elongated member is cut. The method comprises providing a valve where through the elongated member is guided, during an emergency quick disconnect moving a closure element from a first valve open position to a valve closed position and during this movement also cutting the elongated member and actuating a holding assembly of the valve from a retracted position to an extended position wherein the holding assembly is in contact with the elongated member and locks this to the holding assembly when the elongated member is cut. Thereafter reconnecting and then moving a retrieving tool into the well and moving the closure element to a valve open position and then move the retrieving tool into contact with the holding assembly below the closure element, and retrieving the holding assembly with the elongated member locked in the holding assembly to the operator for reconnecting the elongated member to operating equipment.

According to an aspect of the method the actuation of the holding assembly may involve moving a wedge ring is an axial direction and thereby moving wedge elements in a radial direction and into contact with the elongated member. According to another aspect the closure element may be moved in a direction transverse to a bore of the valve.

The invention will now be explained with non-limiting embodiments with reference to the accompanied drawings where;

Fig. 1 shows a cross section of a valve according to the invention an open position, Fig. 2 shows the valve after it has been closed

Fig. 3 shows the valve after is has been closed and ready for retrieval of the cut elongated element.

Fig. 4 is an elevated sketch of a part of the closure element of the valve Fig. 5 is a further detailed image of a detail of the closure element in fig. 4 Fig. 6 is a side view of a wedge ring of the valve Fig. 7 A is an elevated view of one holding element of the valve Fig. 7B is an elevated sketch of three holding element Fig. 8 is an elevated sketch of a base of the valve Fig. 9 is a detail of the base in fig. 8 Fig. 10 is a sketch of a possible configuration of the pressure control head system.

Similar elements are given the same reference numeral in all the different drawings. In the following description there are used phrases as the relative terms below, above, upper and lower. These terms will indicate the relative position of the elements as shown in the drawing and also be the relative normal position of the element when using the valve according to the invention during a wire line intervention in a well. However, these phrases should not be construed as limiting as it will be possible to envisage another relative position during for instance a different use of the valve according to the invention.

In fig. 1 a valve 1 according to the invention is shown in an open position, with an elongated member in the form of a wire line 4 with a tool 5 in the end extending through the valve 1. The valve 1 is as indicated, connected to a pipe 2 above and blow the valve. The same valve is in fig. 2 shown in a closed position. The valve 1 has a valve housing 100 which is connected to the pipe 2, and kept fixed relative to the pipe 2. To the valve housing 100 there is connected actuation means 500 for actuating the valve 1 from an open position to a closed position. The actuation means 500 comprises in this embodiment a chamber 501 and a piston 502 and will be connected to a source of pressurized fluid (not shown) for movement of the piston 502 relative the chamber 501. The actuation means may of course be of a different kind as electrically or magnetically or a combination of these or combined with a hydraulic system. The piston 502 is through connection means 400 in the shown embodiment as a simple rod, but may be different kind of connection means, connected to a closure element 200 of the valve 1. The closure element 200 is arranged movable within the valve housing 100 and will by its movement change the state of the valve 1 from an open position to a closed position, shown in fig. 1 and 2 respectively. The closure element 200 forms a gate element in the shown valve configuration, and will be moved in a direction transverse to an axis of the main bore 3 of the valve 1. There will between the valve housing 100 and the closure element 200 be a sealing arrangement (not shown) such that the valve in a

closed position of the closure element 200 will form a sealing barrier across main bore 3 of the valve 1. The closure element 200, parts of which are shown in more detail in fig. 4 and 5 is formed with a first side 201 facing relatively upwards in the valve 1 in fig. 1 and 2, a first end surfaces 202 facing the actuation means 500 and a second end surface 203, indicated in fig. 2, facing away from the actuation means 500. The part of the closure element 200 forming the second end surface 203 is removed from the part of the closure element shown in fig. 4. The closure element 200 is also formed with a second side surface 204 facing downwards in the drawings, and this second side surface 204 comprises an actuation section 207. In the shown embodiment this actuation section 207 comprises relative to the direction of movement of the closure element 200, an angled surface. This gives that the distance between the first side surface 201 and the second side surface 204 in the area of the actuation section 207 increases in the direction away from the end surface 202 facing the actuation means 500. This gives an increase in a cross section of the closure element, taken across the direction of movement, into a sealing part 206 of the closure element 200, not shown in fig. 4, but indicated in fig. 2. The closure element 200 has further a through going bore 205 which in an open position of the valve will be aligned with the main bore 3 of the valve. Within the bore 205 there is arranged cutting means 208 for cutting an elongated member extending through the valve in an open position. The cutting means 208 is formed by a cutting section 209 of the inner surface of the bore 205, best shown in fig. 5. The cutting section 209 is in the shown embodiment formed by a cut out in the bore 205 at the end of the bore close to the second side surface 204 and closest to the second end surface 203. The cut out will in relation to the bore 205 form a partly withdrawn cutting edge 210 connected to an angled cutting surface 211. The cutting edge 210 is withdrawn from the bore 205 in a direction towards the second end surface 203 and from the second side surface 204 towards the first end surface 201. By having the cutting means 208 withdraw from the main bore 205 one both prevents any unintended damage on the wire line 4 guided through the valve 1 in an open state of the valve 1 and also due to the form of the bore 205 and the cutting means 208 achieves a guidance of the wire line 4 towards the cutting edge 210 when the closure element 200 moves from an open position to a closed position of the valve 1.

The actuation section 207 of the second side surface 204 of the closure element 200 will when the closure element 200 is moved in a direction towards the actuation means 500 from the position as indicated in fig. 1 towards the position indicated in fig. 2, be operable connected to the holding assembly 300 and activate this. The actuation section 207 will due to its angled surface gradually push on the holding assembly 300 as the angled surface of the actuation section 207 will move to more contact with the holding assembly 300 as the closure element 200 moves, until the

sealing part 206 closes the main bore 3 of the valve and the actuation section 207 is moved past the holding assembly 300, as shown in fig. 2.

The holding assembly 300 comprises in the shown embodiment a wedge ring 330, holding elements 320 and a base element 310, as shown as separate parts in fig. 6-8, and assembled in fig. 1 and 2. The base element 310 is formed by a cylinder part 311 with a flange part 313 attached to one end of the cylinder part 31 1. The flange part 313 is extending in radial direction relative the main bore of the valve and be positioned away from the closure element 200 of the valve with the cylinder part extending towards the closure element 200 in an assembled state of the valve. The cylinder part 311 is formed with four through going slits 312, extending from the flange part 313 and for most of the length of the cylinder part 311 but not the whole length, mainly parallel with an axis of the bore of the valve. There is also in the flange part 313 in the side surface facing the cylinder part 311 formed guiding grooves 314 in connection with the slits 312. The grooves 314 also extend in a radial direction. The flange part 313 is formed with a radial outer surface 315 which outer surface 315 will be abutting the main bore of the valve housing 100, as indicated in fig. 1 and 2. The base element 310 will be kept fixed relative the valve housing 100 during the closure of the valve. The base element 310 further has a gripping part 316 arranged in relation to an end surface 317 of the cylinder part 311 , which end surface 317 is facing away from the flange part 313. This end surface 317 is facing towards the closure element 200 and thereby also upwards in the drawings. The gripping part 316 may be of any kind adaptable to interact with a tool for pulling of the base element 310 up through the valve 1. One possible solution is to form a circumferential groove within the cylinder part 311 close to the end surface 317 as indicated in fig. 9.

As said the holding assembly also comprises holding elements 320, in the shown embodiment four holding elements 320, see fig. 7 A and 7B. The holding elements 320 are formed as plate like elements. By plate like elements it should be understood having a width which is smaller than a length and height. The holding elements are arranged moveable in the slits 312 of the base element 310. The holding elements 320 are also guided in their movement by the guiding grooves in the flange part 313. This gives a defined movement of the holding elements 320. The holding elements 320 will move in a radial direction from a retracted state where they are position outside an inner opening of the cylinder part 31 1 of the base element 310, as indicated in fig. 1, to a holding and locking position moved radially inwards through the slits 312 of the base element 310 as indicated in fig. 2. The holding elements are formed with an inner holding surface 321 facing radially inwards when the holding assembly 300 is installed. This inner holding surface 321 will interact with the elongated element 4 which should be hold and locked within the holding assembly 300 when the valve is closed. The inner holding surface 321

may be formed complementary to the elongated element is should hold. The inner holding surface 321 may also be formed with elements for increasing the friction between the inner holding surface 321 and the elongated element 4. The holding element 320 has an end surface 322 facing away from the closure element 200 in an assembled open state of the valve, and arranged abutting the flange part 313 and the guiding grooves 314 of the base element 310. At an opposite end to the end surface 322 there is arranged an angled activation surface 323 extending from an upper end point 325 of the inner holding surface 321 and toward the end surface 322 and away from the inner holding surface 321. This angled activation surface 323 extend downwards to an outer surface 324 facing in a radial direction, opposite the inner holding surface 321. This gives a wedge shape form of the upper part of the holding element 320. The lower part of the holding element 320 has a rectangular shape since the inner holding surface 321 and the outer surface 324 are mainly parallel. The four holding elements 320 will be arranged in each slit 312 of the base element 310 where two and two holding elements 320 are arranged opposite each other.

When the holding assembly 300 is moved to a locking position the holding elements 320 will be moved towards each other towards the centre of the main bore of the valve, giving a relative position of the different holding elements 320 as indicated in fig. 7B. For movement of the holding elements 320 the holding assembly also include a wedge ring 330, as shown in fig. 6. The wedge ring 330 is formed by a main cylinder element 331. This cylinder element 331 has a through going bore 334. The cylinder element 331 has a first end surface 333 facing the flange part 313 of the base element 310. The cylinder element 331 has further as second end surface 335 facing the opposite direction of the first end surface 333. The second end surface

335 is facing the closure element 200 in an assembled state of the valve. The second end surface 335 will in an open position of the valve be in abutment against the second side 204 of the closure element 200. During closing of the valve 1 the movement of the closure element 200 will move the second side 204 along the second end surface 335 of the wedge ring 330. The movement will further bring the actuation section 207 of the closure element 200 in contact with the second end surface 335. This contact will due to the angling of the actuation section 207 increasingly push on the second end surface 335 and thereby the wedge ring 330. Since the wedge ring 330 is arranged within the bore of the valve this pushing from the closure element 200 will move the wedge ring 330 in an axial direction, downwards on the figures. The wedge ring 330 is within the through going bore 334 formed with an inner angled surface section 332. This angled surface section 332 is formed in a part of the through going bore 334. The angled surface section 332 will interact with the angled activation surface 323 of the holding element 320. A movement of the wedge ring 330 in an axial direction will give an interaction between the complementary angled surfaces of the wedge ring 330 and the holding

element 320, and move the holding elements 320 in a radial direction inwards through the slits 312 in the base element 310 as the wedge ring 330 is moved in an axial direction. The holding elements 320 will be in a locking position when they interact with the elongated element. The holding elements 320 will also be in a locking position when the wedge ring 330 is moved in the axial direction until the part of the wedge ring 330 without the inner angled surface section 332 comes in contact with the outer surface 324 of the holding elements 320. A locking position of the valve is shown in fig. 2 of the drawings. When the valve 1 is closed, the closure element 200 may be moved back to a position where a tool may be moved into the valve to interact with the base element 310, for retrieval of the whole holding assembly 300 with the cut elongated element locked in the holding assembly 300, as indicated in fig. 3, where the closure element 200 is moved to a position where the opening through the closure element 200 is aligned with the main bore of the valve and one thereby has access to retrieve the holding assembly with the wire line held fixed within the holding assembly.

A schematic pressure control head system is shown in fig. 10, where the cutting device in the form of a valve arrangement 10 is show in connection with a part of a lubricator for use during intervention in a well. The pressure control head system comprises a cutting device, this may be in the form of a valve comprising a ball shaped closure element 12. This ball shaped closure element 12 is operable connected as indicated by the dotted line 11 to the holding device or the holding assembly 13 in the shown embodiment as a dual stuffing box. The dual stuffing box will in this embodiment also act as the sealing section of the system according to the invention. The movement of the closure element 12 will cut the wire line 4 and activate the holding assembly 13. The cut wire line 4 is thereby retrievable by a tool instead of dropped into a λvell. The valve explained in relation to fig. 1-9 may replace the ball shaped closure element in the configuration shown in fig. 10.

The invention has now been explained with non-limiting embodiments. A skilled person will understand that there may be made alternations and modifications to the embodiments described that are within the scope of the invention as defined in the attached claims. The cutting means in the form of the cut out in the closure element may be made on an end of the closure element instead of within a bore in the closure element. The may be more or less than four holding elements and slits. There may be arranged non-return elements within the slits or guiding grooves in the base element for the movements of the holding elements. There may be arranged preventing means as safety pins in relation to the movement of the holding elements to prevent inadvertently movements of these. The closure element may be a ball element and it might be the rotational movement that activates the holding assembly. The guiding grooves in the flange part may as an alternative be guiding

track, i.e. in relation to the flange part raised guiding elements rather than sunken guiding elements.