GB2389378A

GB2389378A - Downhole device operation

Info

Publication number: GB2389378A
Application number: GB0211021A
Authority: GB
Inventors: Steven Martin Hudson
Original assignee: Flight Refuelling Ltd
Current assignee: Cobham Mission Systems Wimborne Ltd
Priority date: 2002-05-14
Filing date: 2002-05-14
Publication date: 2003-12-10
Also published as: GB0211021D0

Abstract

A downhole tool setting device comprising a member (6) arranged to be moveable under the action of ambient downhole pressure and control means, in the form of a latch (10), for controlling movement of the moveable member under the action of the ambient downhole pressure.

Description

Downhole device operation This invention relates to the operation of

downhole devices.

5 Various devices must be operated in downhole situations by which it is meant below the surface in wells, typically within the oil and gas industry. Wherever a device has to be operated a source of power is needed in order to bring about that operation. lo downhole situations there are a number of options available for providing power, such as using batteries or supplying power from a remote lo location via an electrical connection. However, each of these methods has associated disadvantages.

it is an object of this invention to provide a different way of operating downhole devices.

According to one aspect of the present invention there is provided a downhole device comprising a member arranged to be moveable under the action of ambient downhole pressure and control means for controlling movement of the moveable member under the action of the ambient downhole pressure.

According to another aspect of the present invention there is provided a method

of operating a downhole device using the awhient downhole pressure to drive the device.

According to yet another aspect of the present invention there is provided a s method of operating a downhole device using the ambient downhole pressure comprising the steps of arranging a member of the device to be moveable under the action of ambient downhole pressure and using control means to control movement of the moveable member under the action of the ambient downhole pressure.

]O It will be understood that ambient downhole pressure means that pressure that surrounds the device when downhole and acts on any external surface of the device. 15 In such a device and method the control means is used for controlling the ability of the ambient pressure to move the moveable member. There are two; main ways in which this can be achieved in one case the control means determines whether the ambient pressure can cause a force to act on the moveable member tending to make it move and in the other case the control 20 means determines whether the moveable member is free to move. In said other case the moveable member may be permanently subject to the action of the

ambient pressure, this may be by direct exposure to the pressure.

The device may comprise a main body relative to which the moveable member is arranged for movement. The control means may comprise holding means for holding the moveable member against movement relative to the main body.

s Typically the holding means will be releasable holding means. The holding means may comprise a latch.

The moveable member may comprise a piston. The main body may comprise a cylinder within which the piston is arranged for movement. It will be lo understood that the expression cylinder is used in this specification in the sense

of vessel within which a piston can move and there is no suggestion that the cylinder need be of cylindrical shape.

The main body may comprise a chamber which is sealable against ambient is pressure. Al least one surface of the chamber may be defined by the moveable member. The pressure in and/or the volume of the chamber may be alterable by movement of the moveable member. The chamber may be defined by walls of the cylinder and a face of the piston.

20 The downhole device may have a prepared state in which the moveable member is in a prepared position from which the moveable member is

moveable under action of ambient pressure and an operated state in which the moveable member is in another position.

The device may be prepared for operation by arranging the interior of the 5 chamber to be at a first pressure which is lower than the ambient pressure where the device is to be operated. The device may be prepared by sealing the chamber during assembly so that the pressure in the chamber is substantially the same as the environmental or atmospheric pressure where assembly occurs.

10 In a method of using the device, the device may be prepared at a first location having a first pressure and moved to a second location for operation, the ambient pressure at the second location being higher than the first pressure.

The first location may be at the surface. The second location will be downhole.

15 According to a particular aspect of the invention there is provided a downhole device comprising a main body having a cylinder, and a piston arranged for movement in the cylinder, walls of the cylinder and a face of the piston at least partially defining a chamber sealable against ambient pressure, the piston being subject to the action of ambient pressure but being held in a first position by 20 releasable holding means, and the arrangement being such that when the holding means is released, if the ambient pressure exceeds the pressure in the

chamber, the piston will move in the cylinder under action of the ambient pressure. The movement of the moveable member under action of the ambient pressure 5 may be used as a source of drive. The moveable member may be connected to other members.

The downhole device may comprise return means for returning the device towards the prepared state from the operated state. Where the device comprises 10 a chamber sealed against ambient pressure, the return means may comprise means for opening the chamber to ambient pressure. This can facilitate the movement of the moveable member in a direction opposite to that which occurs under action of the ambient pressure. The return means may comprise spring means, which may be disposed in the chamber for acting on the 15 moveable member.

The control means may comprise triggering means arranged to allow the moveabJe member to be moved under the action of ambient pressure when predetermined conditions are met. The control means may comprise receiver 20 means for receiving signals from a remote location. The control means may comprise sensor means for sensing at least one parameter such as temperature

or pressure. The control means may comprise timer means. The predetermined conditions may comprise any one of or any combination of: reception of predetermined signals, sensed parameters reaching predetermined values, elapsing of predetermined time periods. One specific set of trigger conditions 5 which is currently envisaged comprises waiting for a predetermined period to elapse after sensing of a predetermined pressure with a predetermined temporal stability. The downhole device may be an actuator device which is arranged for 10 operating and/or controlling the operation of another device. Such an actuator device might be retrofitted to existing components. Alternatively the downho]e device may be a fully functional device in its own right.

In one development of the invention the downhole device comprises a 15 downhole setting tool. Setting tools per se are well known. The function of such tools is to secure the tool, and any item attached to it, within a downhole bore such as a weld casing or production string. Typically setting tools operate by wedging the tool in place by forcing suitable wedging members outwards.

20 In a setting tool embodying the present invention wedging means may be provided and arranged to be driven by movement of the moveable member.

The wedging means may comprise at least one wedging member having a contact portion arranged to be driven outwards from a central axis of the tool.

Such a contact portion is provided for contacting with the internal surface of a surrounding bore. The wedging member may be pivotally mounted with respect 5 to the moveable member. The device may be arranged so that the contact portion of the wedging member is forced outwards by action of a bearing surface of the main body on said wedging member as the pivotal mounting point of the wedging member is moved relative to the bearing surface by virtue of movement of the moveable member.

The setting tool may comprise upsetting means for retracting the wedging means. This can facilitate later removal of the tool. Where the device comprises a chamber sealed against ambient pressure, the upsetting means may comprise means for opening the chamber to ambient pressure. This can 5 facilitate the movement of the moveable member in a direction opposite to that which occurs during setting. The upsetting means may comprise retracting means for driving the wedging means towards a retracted position. The retracting means may comprise spring means, which may be disposed in the chamber for acting on the moveable member.

In some instances a downhole actuator device of the present invention may be

provided for use in operating a distinct setting tool.

An embodiment of the present invention will now be described by way of example only with reference to the accompanying drawings in which: Figure I shows a downhole setting tool embodying the invention which is located in tubing of a well; Figure 2 shows the setting tool of Figure I in a configuration reached after 10 operati on.

Figure I shows a setting tool I disposed within tubing 2 of a well and in a prepared state whereas Figure 2 shows the tool in an operated state.

15 As mentioned above, the function of setting tools per se is well known, their purpose being to securely locate the setting tool itself and any attached item at a desired position within tubing. In the present case the setting tool I is attached to another tool 3 such that this other tool 3 is also secured in the desired position within the tubing 2.

Different ways can be envisaged for securing or setting a setting tool I within

tubing 2. In the present case the exact mode of setting is of less interest than the mechanism used in order to drive the setting tool into the set position.

Typically setting will be achieved by wedging suitable wedging members 5 against the interior surface of the tubing 2.

In the present embodiment the wedging members comprise a pair of extending arms 4 which can be moved between a retracted position as shown in Figure 1 and an extended wedging position as shown in Figure 2. As can be seen in 10 Figure 2, when the extending arms 4 are in the extended position, contact portions 4a of the extending arms 4 make contact with the interior surface of the tubing 2. Provided that sufficient force is provided to urge the extending arms 4 outwards into contact with the tubing 2, a very secure location of the setting tool 1 can be achieved.

Each of the extending arms 4 is pivotally connected to a drive rod which in turn is connected to a piston 6. The piston 6 is arranged to move within a cylinder 7 provided within a main body 8 of the tool.

20 A chamber 9 is defined within the main body 8 by walls of the cylinder 7 and a face of the piston 6. This chamber 9 is, in normal circumstances, sealed from

the ambient pressure surrounding the tool 1. Furthermore, the device is arranged so that in normal operating conditions when the piston 6 is in the prepared position, as shown in Figure l, pressure in the chamber 9 is much lower than the ambient downhole pressure surrounding the tool 1. In practice 5 this may be achieved by simply manufacturing or assembling the tool 1 at the surface such that the chamber 9 is filled with air at atmospheric pressure.

Once the tool is moved to a downhole location where the ambient pressure is much higher, the desired pressure differential between the chamber 9 and the surroundings will naturally occur.

It will be appreciated that such a pressure differential will tend to force the piston 6 to move within the main body 8 to decrease the volume of the chamber 9 and correspondingly increase the pressure therein.

lS However, a releasable latch mechanism 10 is provided to hold the piston 6 against such movement. The presence of the latch 10 allows the setting tool 1 to be lowered into position downhole with the piston 6 unable to move and the extending arms 4 remaining in the retracted position.

20 On the other hand, once the releasable latch lo is released, the piston 6 is able to move within the cylinder 7 reducing the volume of the chamber 9 and

1 1 pulling the drive rod 5 towards the remainder of the tool 1. As the drive rod 5 is pulled towards the remainder of the tool, the point where each extending arm 4 is pivotally connected to the drive rod 5 is also pulled towards the remainder of the tool. As this movement occurs the extending arms 4 ride along s respective bearing surfaces Sa of the main body 8 and are driven outwards into contact with the surrounding tubing 2 and into the extended position shown in Figure 2.

Thus, the setting tool I is operated by action of the ambient pressure and no lo dedicated power source is required to provide the necessary force to wedge the setting tool l into position.

The setting tool 1 further comprises return means for returning the extending arms 4 towards the retracted position as shown in Figure 1. This can facilitate 15 later removal of the setting tool 1 from the tubing 2. In the present embodiment the retune means comprises a controllable valve (not shown) which can be opened to allow the ambient pressure into the chamber 9 and a: return spring 1 l provided within the chamber 9, and arranged to act on the piston 6. When the tool 1 is in the operated state as shown in Figure 2, if the 20 valve (not shown) is opened, there is sufficient energy stored in the return spring 11 to drive the piston 6, and hence the drive rod 5 and extending arms

4, back towards the retracted position as shown in Figure 1. It will be appreciated that it is not necessarily a requirement that the return means is able to return the extending arms 4 completely to their initial position as long as sufficient movement is obtained to disengage the arms 4 from the tubing 2.

An electronics control module 12 is provided for controlling the operation of the releasable latch 10 and the controllable valve (not shown). In particular, the electronics module 12 is used to control when the releasable latch 10 is released to allow setting of the tool 1 and when the controllable valve (not lo shown) is opened to allow upsetting of the tool 1. The electronics module 12 can control these operations on the basis of various predetermined conditions.

In particular, it is envisaged that the electronics module comprises timing means, receiving means for receiving signals from a remote location, and sensor means for sensing local parameters such as pressure and/or temperature.

l5 Any one of, or any combination of, delays timed by the timing means, signals received by the receiving means and parameters sensed by the sensor means may be used to trigger setting and upsetting of the tool 1.

As a particular example, the too] I can be arranged so that the setting operation 20 of the setting tool 1 will only be initiated when a predetermined time has elapsed after a predetermined pressure has been sensed and it has been

]3 determined that this pressure has gained a predetermined temporal stability Such a method allows the controlled setting of the tool at a location having a desired pressure and avoids the possibility of the tool being inadvertently set due to short lived or anomalous pressure fluctuations.

In various developments and alternatives, an additional setting device might be provided on the tool 1 for redundancy reasons. Further, where a tool 1 is deployed using a wireline or coiled tubing' the coiled tubing or wire line can be tensioned after the tool 1 has been set to confirm the integrity of the setting 10 device. In a further development, where the tool 1 has transmitting capabilities which make use of the tubing 2 as a conduction path (such as those described in WO 01/04461), the too] 1 can be arranged to transmit a signal at a predetermined ]5 time after setting. This signal can then be looked for at a remote location, for example, the surface. The receipt of a signal with expected strength can be taken as an indication that good electrical contact must have been achieved between the setting tool I and the tubing 2 and thus the too] 1 must be correctly set within the tubing 2.

An alternative or additional method of recovery may be provided instead of, or

in addition to the returning feature described above. In such a case the extending arms 4 may be retained using shear pins having a defined strength to upward and downward loads. In such a case the fixing between the tubing 2 and the tool 1 may be broken by the application of a suitably large downward 5 or upward force.

Whilst the specific description above has been directed to the example of

operating a setting tool, it will be appreciated that the present invention is of wider applicability in that ambient pressure may be used to drive a large

10 number of different downhole devices.

Claims

CLAIMS:

1. A downhole device comprising a member arranged to be moveable under the action of ambient downhole pressure and control means for controlling movement of the moveable member under the action of the ambient downhole 5 pressure.

2. A downhole device according to claim 1 in which the condo] means is arranged to determine whether the ambient pressure can cause a force to act on the moveable member tending to make it move.

3. A downhole device according to claim 1 in which the control means is arranged to determine whether the moveable member is free to move.

4. A downhole device according to any preceding claim in which the device 15 comprises a main body relative to which the moveable member is arranged for movement.

5. A downhole device according to claim 4 in which the control means comprises holding means for holding the moveable member against movement 20 relative to the main body.

6. A downhole device according to claim S in which the holding means comprises a latch.

7. A downhole device according to any one of claims 4 to 6 in which the 5 movable member comprises a piston, and the main body comprises a cylinder within which the piston is arranged for movement.

8. A downhole device according to any one of claims 4 to 7 in which the main body comprises a chamber which is sealable against ambient pressure, at 10 least one surface of the chamber being defined by the moveable member and the pressure in and/or the volume of the chamber being alterable by movement of the moveable member.

9. A downhole device according to any preceding claim which has a prepared 15 state in which the moveable member is in a prepared position from which the moveable member is moveable under action of ambient pressure and an operated state in which the moveable member is in another position.

10. A downhole device according to claim 9 when dependent on claim 8 20 wherein during operation and in the prepared state, the interior of the chamber is at a first pressure which is lower than the ambient pressure where the device

is to be operated.

11. A downhole device according to claim 1, comprising a main body having a cylinder, and a piston arranged for movement in the cylinder, walls of the s cylinder and a face of the piston at least partially defining a chamber sealable against ambient pressure, the piston being subject to the action of ambient pressure but being held in a first position by releasable holding means, and the arrangement being such that when the holding means is released, if the ambient pressure exceeds the pressure in the chamber, the piston will move in 10 the cylinder under action of the ambient pressure.

12. A downhole device according to claim 9 or claim 10 comprising return means for returning the device towards the prepared state.

15

13. A downhole device according to claim 12 in which the return means . comprises spring means.

14. A downhole device according to any preceding claim in which the control means comprises triggering means arranged to cause the control means to allow 20 the moveable member to be moved under the action of ambient pressure when predetermined conditions are met.

15. A downhole device according to any preceding claim which is an actuator device which is arranged for operating and/or controlling the operation of another device.

s

16. A downhole device according to any preceding claim which comprises a downhole setting tool operable by the action of ambient downhole pressure.

l7. A downhole device according to claim 16 in which the setting tool comprises at least one wedging member arranged to be driven outwards by 10 movement of the movable member.

18. A method of operating a downhole device using the ambient downhole pressure to drive the device.

IS

19. A method of operating a downhole device using the ambient downhole pressure, comprising the steps of arranging a member of the device to be moveable under the action of ambient downhole pressure and using control means to control movement of the moveable member under the action of the ambient downhole pressure.