WO2009123467A1

WO2009123467A1 - Impact sub device

Info

Publication number: WO2009123467A1
Application number: PCT/NO2009/000116
Authority: WO
Inventors: Espen Osaland; Lasse Haugland
Original assignee: Aker Well Service As
Priority date: 2008-04-03
Filing date: 2009-03-30
Publication date: 2009-10-08
Also published as: NO20081653L; NO332476B1

Abstract

An impact sub device (1) for use in a borehole where the impact sub device (1) in its first end portion (32) is connected to an object (8) to which a blow shall be imparted, and where the impact sub device (1) in its second end portion (18) is connected to an in the borehole (2) attachable actuator (4).

Description

IMPACT SUB DEVICE

There is provided an impact sub device. More particularly it concerns an impact sub device for use in a borehole where the impact sub device in its first end portion is connected to an object to a blow shall be imparted.

During work in a borehole where an object such as a tool or a component in the borehole is to be moved, it may be necessary to impart a blow to the object to make it come loose from its position.

It is known to connect an impact sub device to a coiled tubing or to a wireline. It is, however, by use of the prior art only possible to apply a relatively modest tension force to the impact sub device. The situation is also well known from work in long, substantially horizontal boreholes where it is often necessary to use a well tractor to reach the object.

The object of the invention is to alleviate or reduce at least one of the prior art drawbacks .

The object of the invention is achieved by the features disclosed in the description below and in the following claims.

There is provided an impact sub device for use in a cased or uncased borehole, the impact sub device in its first end portion being connected to an object to be dealt a blow, and where the impact sub device is characterised in that it in its second end portion is connected to an in the borehole fixable actuator.

By connecting the impact sub device to an actuator, which is fixable in the borehole, it has turned out to be possible to increase the tension force of the impact sub device, and thereby the impact energy substantially compared to prior art.

According to one aspect of the impact sub device, the impact sub device in its first end portion is provided with a tool mounting for connection to the object, and in its second end portion provided with an actuator mounting, as at least one main spring is fixably connected between the actuator mounting and a housing of the impact sub device, and where the tool mounting is displacebly and releasably connected to the housing. A displacement of the actuator mounting beyond a predetermined distance from its starting position relative to the housing, whereby the at least one main spring is compressed, causes the stop element provided to hold the tool mounting engaged in the housing to loose its locking posi- tion, whereby the housing is arranged to be able to be freed from its locked position relative to the tool mounting and, due to the at least one compressed main spring, is arranged to be able to impart a blow to the tool mounting.

Another aspect of the impact sub device is that the stop ele- ment is displaceable relative to the actuator mounting. The actuator mounting and the housing may thereby be displaced back toward their respective starting positions relative to the tool mounting without the stop element being displaced relative to the actuator mounting.

A further aspect of the impact sub device is that a cone portion connected to the actuator mounting is arranged to be able to displace the tool mounting locking hooks to engagement in the housing when the actuator mounting is near the tool mounting .

Another aspect of the impact sub device is that the stop ele- ment is pre-tensioned displacebly in between the locking hooks when the housing is in its starting position relative to the tool mounting.

The manner of operation of the impact sub device is explained in the special part of the description.

The provided impact sub device makes possible the use of blows carrying relatively large energy in areas of a borehole where earlier the access for such tools was limited. The impact sub device is particularly well suited for use together with an actuator, often called "stroker" in the art, where the actuator is connected to a well tractor.

In the following is described an example of a preferred embodiment which is illustrated in the accompanying drawings, where :

Fig. 1 shows schematically an impact sub device in a bore- , hole where the impact sub device is connected to an actuator and to an object to which blows shall be imparted;

Fig. 2 shows in greater detail a longitudinal section of the impact sub device in its starting position;

Fig. 3 shows a part of the impact sub device of Fig. 2 in additionally larger scale, where the impact sub device is being tensioned;

Fig. 4 shows the impact sub device of Fig. 3 as the blow is delivered; . Fig. 5 shows the impact sub device of Fig. 3 after a blow has taken place;

Fig. 6 shows the impact sub device of Fig. 3 while the impact sub device is being brought back to its start- 5 ing position; and

Fig. 7 shows the impact sub device of Fig. 3 just before the impact sub device is in its starting position.

In the drawings, the reference numeral 1 indicates an impact sub device in a possibly cased borehole 2 and connected to an io actuator 4 by an actuator mounting 6 and to an object 8 which is to be imparted a blow, via a tool mounting 10. The actuator 4 which is connected to a well tractor 12 is provided with clamp bars 14 which in a per se known manner are arranged to be able to clamp the actuator up against the bore- i5 hole 2.

The impact sub device 1 comprises a housing 16, which due to production technical conditions is assembled from a number of tubular sections.

The actuator mounting 6 at the second end portion 18 of the 20 impact sub device 1 extends into the housing's 16 axial through bore 20. The actuator mounting 6 is also assembled from a number of axial components. Two main springs 22 surrounding the actuator mounting 6 in the housing 16, are ten- sioned between the respective spring shoulders 24 in the 25 housing 16 and spring supports 26 on the actuator mounting 6. The spring support 26 being closest to the tool mounting 10 is limited displaceable along the actuator mounting 6.

A displacement of the actuator mounting 6 in a direction toward the second end portion 18 causes the main springs 27 to 3o be tensioned. In its starting position, the actuator mounting 6 abuts an anchor 28, which is fixedly connected to the housing 16.

A pair of breaking elements 30 locks the actuator mounting 6 in the housing 8 before the impact sub device 1 is to be ac- tivated.

The tool mounting 10 extending into the bore 20 from the first end portion 32 of the impact sub device 1 is provided with an axially slotted locking element 34. The locking element 34 is provided with a number of locking hooks 36 which are radially displaceable into a locking recess 38 in the housing 16.

A stop element 40 which is axially displaceable in a stop bore 42 in the actuator mounting 6, extends in between the locking hooks 36 in the starting position and prevents the locking hooks 36 from being able to be displaced out of the locking recess 38.

A stop spring 44 in the stop boring 42 is provided for tensioning the stop element 40 in a direction toward the tool mounting 10. A cone portion 46 surrounding the stop element 40 and connected to the actuator mounting 6 prevents the stop element 40 from being able to be displaced all the way out of the stop bore 42 by a stop shoulder 48 coming into abutment against the cone portion 46.

The housing 16 is at its first end portion 32 provided with an impact shoulder 48, which is arranged to abut an impact shoulder 50 on the tool mounting 10.

The impact sub device 1 is rotationally symmetrical about its longitudinal axis. When the impact sub device 1 is to be activated, the actuator's 4 clamp blocks are forced against the borehole 2 wall. The actuator 4 thereafter displaces the actuator mounting 6 such that the breaking elements 30 are cut, whereafter the main springs 22 are tensioned at the same time as the stop element 40 is displaced axially between the locking hooks 36, see Fig. 3.

As the stop element 40 looses its grip between the locking hooks 36, see Fig. 4, the locking hooks 36 are displaced out from their grip in the locking recess 38.

The housing 16, which is tensioned by means of the main springs 22, is arranged to be displaced at high speed in the direction toward the second end portion 18 until the impact shoulder 48 abuts the impact shoulder 50, whereby the tool mounting 4 is given a blow which is transferred to the tool 8, without any real impact power being given to the actuator mounting 2, see Fig. 5. At the same time the anchor 28 comes to a somewhat dampened abutment against the actuator mounting 6. The damping is due to the limited displacement ability of the spring support 26 relative to the actuator mounting 6.

In this released position the main springs are practically unloaded.

If it is necessary to give the object 8 an additional blow, the actuator 4 displaces the actuator mounting 6 and the housing 16 in the direction toward the first end portion 32 while the stop element 40, which is prevented from being able to be displaced in between the locking hooks 36 are displaced into the stop boring 42 at the same time as the stop spring 44 is compressed, see Fig 5.

When the tool mounting 10 has reached its starting position in the housing 16, the locking hooks 36 will, due to pre- loading in the locking element 34 and power from the cone portion 46 be displaced into the locking recess 38. The stop spring 44 thereby displaces the stop element 40 in between the locking hooks 36, whereby the impact sub device 1 is re- verted to its starting position and made ready for a new impact cycle.

Claims

C L A I M S

1. An impact sub device (1) for use in a borehole, the impact sub device (1) in its first end portion (32) being connected to an object (8) to which a blow shall be imparted, c h a r a c t e r i s e d i n that the impact sub device (1) in its second end portion (18) is connected to an actuator (4) attachable in the borehole (2) .

2. An impact sub device (1) according to claim 1, c ha r a c t e r i s e d i n that the impact sub device (1) in its first end portion (32) is provided with a tool mounting (10) for connection to the object (8) , and in its second end portion (18) is provided with an actuator mounting (6) , wherein at least one main spring (22) is compressibly connected between the actuator mounting (6) and the housing (16) of the impact sub device (1) , and wherein the tool mounting (10) is displaceably and releasably connected to the housing (16) , as a displacement of the actuator mount- ing (6) beyond a predetermined length from its starting position relative to the housing (16) , whereby at least one main spring (22) is compressed, causes the stop element (40) which is arranged to hold the tool mounting (10) in engagement with the housing (16) , looses its locking position, whereby the housing (16) is arranged to be able to be released from its locked position relative to the tool mounting (10) and due to the at least one compressed main spring (22) is arranged to be able to impart a blow to the tool mount- . ing (10) and thereby to the object (8) .

3. An impact sub device (1) according to claim 2, c h a r a c t e r i s e d i n that the stop element (40) is displaceable relative to the actuator mounting (6) .

4. An impact sub device (1) according to claim 2, c h a r a c t e r i s e d i n that a cone portion (46) connected to the actuator mounting (6) is arranged to be able to displace the locking hooks (36) of the tool mounting (10) into engagement with the housing (16) when the actuator mounting (6) is close to the tool mounting (10) .

5. An impact sub device (1) according to claim 4, c h a r a c t e r i s e d i n that the stop element (40) is pre-tensioned displaceable in between the locking hooks (36) when the housing (16) is in its starting position relative to the tool mounting (10) .