EP0206917B1 - Apparatus and method for the temporary protection of a workover or logging tool fastened to the end of a string - Google Patents

Description

The present invention relates to a device and method for protecting a measuring instrument (probe) or a specialized tool for intervention in a well, this tool being fixed to the end of a column.

In the devices and methods of the prior art, the tool or instrument is brought out of its casing, or protective casing, by a movement of this tool or instrument relative to the column and the casing, the latter being fixed relative to the column.

Such an operating mode has many drawbacks. In fact, very often specialized tools, such as logging probes, require an electrical connection with the surface of the well. This connection is generally made by cable and it is therefore necessary to provide members which ensure the electrical continuity of the connection when the tool is moving. Such organs are in particular fragile and present implementation difficulties.

Furthermore, very often, the devices according to the prior art move the tool by pumping the liquid inside a hollow column. This has the effect of violently propelling the probe with risks of damage to it, especially if the well is obstructed.

The prior art can be illustrated by French patent FR-A-2,547,861, European patent EP-A-0 122 839 and American US-A-4 349 072.

The present invention overcomes these drawbacks by providing a retractable protection device for a specialized instrument or tool for intervention in a well, this tool or instrument being fixed to the end of a column.

The device according to the invention comprises a casing, or protective casing, of said tool or instrument and is characterized in that the column comprises substantially at its end, and before said tool or instrument, a first guide member and in that the housing comprises a second guide member, these first and second guide members being adapted to cooperate with each other in order to allow the displacement of the housing relative to the tool or instrument.

The device according to the present invention may include means for anchoring and locking the casing relative to the assembly formed by said column and said tool or instrument.

These anchoring means may be adapted to immobilize the casing when the latter protects the tool or instrument, or when it does not protect said tool or instrument. The casing may include centering means in the well.

The device according to the present invention may include means for moving the casing relative to the assembly formed by said column and said tool or instrument.

The present invention also relates to a method of protection using a protective casing or casing of an instrument or specialized tool for intervention in a well, this tool or instrument being fixed to the end of a column.

The method according to the invention is characterized in that the casing is slidably mounted relative to the assembly consisting of the tool or instrument and the column.

According to the present invention, it is possible to move the assembly consisting of the column and the tool or instrument to remove the latter from its protective casing. Thus, the housing remains substantially stationary relative to the well.

It will not depart from the scope of the present invention if, to intervene with the tool or instrument in a given zone of the well, the assembly consisting of the column and the casing is moved beyond this zone while the latter is in the protective position of the tool or instrument and the tool is discovered when moving, or just before moving this assembly in the opposite direction and before reaching the intervention area again.

• les figures 1 et 2 illustrent un mode simple de réalisation du dispositif selon l'invention,
• les figures 3 et 4 illustrent un deuxième mode de réalisation selon lequel le dispositif suivant l'invention comporte des moyens de centrage du carter dans un puits, et
• les figures 5 et 6 montrent un troisième mode de réalisation selon lequel ledit carter est déplacé par des moyens hydrauliques.
• La figure 1 illustre un mode de réalisation simple du dispositif selon l'invention.

The present invention will be better understood and its advantages will appear more clearly on reading the following description, of particular examples which are in no way limiting, illustrated by the appended drawings among which:

• FIGS. 1 and 2 illustrate a simple embodiment of the device according to the invention,
• FIGS. 3 and 4 illustrate a second embodiment according to which the device according to the invention comprises means for centering the casing in a well, and
• Figures 5 and 6 show a third embodiment in which said housing is moved by hydraulic means.
• FIG. 1 illustrates a simple embodiment of the device according to the invention.

The reference 1 designates a tool or instrument to be discovered temporarily. This tool which can be a logging probe or any other tool is fixed to a column 2 which can be a drill string, by means of a first guide member 3 which in the case of FIG. 1 is a cylinder .

Reference 4 designates a protective casing or envelope. This casing comprises a second guide member 5, such as bearings which can slide on the first guide member 3.

FIG. 1 shows the casing 4 in the tool protection position 1.

The casing 4 can be held in this position by means of anchoring or locking means 6. In FIG. 1, these locking means comprise dogs 7 retractable. These dogs can be remotely controlled electromagnetically.

Such anchoring devices being well known to those skilled in the art, will not be described in detail here.

When it is desired to discover the tool 1, as shown in FIG. 2, the dogs 7 are retracted and the casing 4 is moved so as to uncover the tool to be protected 1 which can then be activated to perform the operations for which it is intended.

In the example shown in Figure 1, the tool to be protected and the locking means 6 of the housing on the guide member, require an electrical connection with equipment located, for example, on the surface.

A male connector 8 fixed inside the column will allow this connection. A connector female 9 fixed to the end of a cable 10 is adapted to cooperate with the male connector 8. The female connector 9 can be lowered into the column by gravity or / and possibly by pumping.

The exit and withdrawal of dogs 7 may be controlled by electrical signals transmitted by conductors incorporated in the column.

There are several ways to move the housing.

In what follows, several modes of movement will be indicated which are in no way limited to the present invention.

In the case where the friction of the casing on the walls of the well is sufficiently greater than that of the casing on the probe, it will be possible to have locking means 6 which immobilize the probe in its protective position illustrated in FIG. 1. Thus, when the tool is lowered, it remains protected.

When it is desired to discover the tool, the erasing of the locking means 6 is controlled, for example by electrical signals transmitted by the cable 10 and the connectors 8 and 9. It is then enough to push on the column to bring out the tool 1 of the casing 4, as is the case in FIGS. 2 and 4.

The casing 4 will not advance if the forces which retain it and which are due to the forces between the casing and the walls of the weight of the well are sufficient to overcome the driving forces which result from the forces of friction of the casing on the probe and possibly the weight of the housing. Of course, the forces due to the weights of the casing do not intervene in the case where the exit of the probe takes place in a horizontal portion of a well.

It is obvious that if the tool is to be moved in the direction of an increasing penetration into the well, while being removed from its housing, it will not be necessary to lock the housing 4 in the tool extended position. .

On the other hand, if the tool must be moved in the opposite direction, while being removed from its casing, it will be necessary to lock the latter in the tool-out position.

This could be achieved, for example, by means of second anchoring or locking means which may include dogs 11 (fig. 4). Of course, it will not depart from the scope of the present invention by using unique anchoring or locking means, adapted to immobilize the casing in the extended tool position and in the retracted tool position.

Figures 3 and 4 show the case where the protective casing 4 is equipped with centralizers 12 and 13. This centralizer can be of the blade type.

The use of a centering device makes it possible to maintain the casing in the center of the well and consequently the tool in the case where it is centered relative to the casing. Furthermore, in certain cases, it is the centralizers which induce a frictional force between the casing and the well 14.

Furthermore, the embodiment of Figures 3 and 4 shows a device according to the invention comprising first anchoring or locking means 7 of the housing in protected probe position and second anchoring or locking means 11 of the housing 4 in probe 1 output position (fig. 4).

The first locking means comprise dogs 7 which cooperate with an axial support 15 integral with the tool 1 to define a space which will limit the movement of the second guide member 5 which, in this case, will also play the role of axial stop.

It is the same for the second locking means. The displacement of the second guide means 5 which serve as axial stops is limited on the one hand by an axial support 16 integral with the column and by the dogs 11.

The dogs of the first and second locking means are included in the space defined by the support means secured to the tool and by the support means secured to the column.

Figures 5 and 6 show the casing in the protected probe and probe out position respectively.

In the case of these figures, the displacement of the casing is obtained by hydraulic means.

The device shown in FIGS. 5 and 6 comprises a hollow column 2 and a passage 17 passing through the first guide member 3.

The passage 17 opens at one of its ends in the column 2 through an orifice 18 and at its other end in a chamber 19 defined by the second guide member 5 and the support 15 secured to the tool by an orifice 20 .

In the upper part of the casing, a clearance 21 has been arranged, in order to better allow the pressure forces to cause the displacement of the casing 4 in the position of the probe extended, when the inking or locking means 7 are erased.

Thus, when the fluid is pumped inside the column, it passes through the passage 17, ends in the clearance 21 and causes the expansion of the chamber 19 and the rise of the casing 4. This operation is equivalent to that of a jack.

The casing 4 may include orifices 22 located at the lower part of the casing 4 so that these orifices are uncovered when the probe is out. This will allow the circulation of pumped fluid.

The device shown in Figure 6 includes locking or inking means 11 of the housing in the tool out position.

To move the casing to the protected probe position, after the pumping of the fluid has been stopped, the erasing of the locking means 11 of the casing and pulled on the column 2 can be canceled until the casing 4 covers the tool 1, then engage the first locking means 7.

Of course, other means can allow the casing to be moved into the protected tool position, in particular hydraulic systems opposite to those described above, the operation of which would be equivalent to that of a double-acting cylinder.

The control of the various valves necessary for the operation of such a device equivalent to a double-acting cylinder could be carried out by electrical signals or by information transmitted by the fluid circulating in the column, in particular by inserting flow detectors or pressure.

It is obvious that if the female connector 9 is lowered by pumping, it will be possible to provide a flow circulation orifice in the lower part of the column. This hole may be blocked when the female connector is in place.

According to an embodiment of the device according to the present invention, it will be possible, when it is desired to intervene on a given zone of the well, to lower the tool and the casing beyond the intervention zone, the housing then in the protected tool position, then take out the tool and return to the intervention area.

Such a mode of operation avoids entering the well with the tool extended and therefore avoids destroying the tool against an obstruction element located in the well such as scree.

Claims (9)

1. Retractable device for protecting a specialised instrument or tool for intervention in a well, said tool being fixed to the end of a string, this device comprising a casing to protect said tool or instrument, characterised in that said string (2) comprises a first guiding element (3) substantially at its end and before said tool (1) and in that said casing (4) comprises a second guiding element (5), said first and second guiding elements being adapted to cooperate together in order to allow the movement of said casing (4) relative to said tool or instrument (1 ).

2. Device as in Claim 1, characterised in that it comprises means (6) for locking said casing (4) relative to the assembly constituted by said string (2) and said tool or instrument (1).

3. Device as in Claim 2, characterised in that said locking means are adapted to immobilise said casing (4) when the latter is in its position (Figure 1) protecting said tool or instrument (1).

4. Device as in Claim 2, characterised in that said locking means (11) are adapted to immobilise said casing (4) when the latter is not protecting said tool or instrument (Figure 4).

5. Device as in Claim 1, characterised in that it comprises means (12, 13) for centering said casing (4) in the well.

6. Device as in Claim 1, characterised in that it comprises means for moving said casing (4) relative to the assembly constituted by said string (2) and said tool or instrument (1).

7. Method for protecting a specialised tool or instrument for intervention in a well with the aid of a casing, said tool or instrument being fixed to the end of a string, characterised in that said casing (4) is fitted so that it can slide relative to the assembly constituted by said tool (1) and said. string (2).

8. Method as in Claim 7, characterised in that the assembly constituted by said string (2) and said tool or instrument (1) is moved to remove the latter from its protective casing (4).

9. Method as in Claim 7, characterised in that in order to intervene with said tool or instrument (1) in a given zone of the well, the assembly constituted by said string (2) and said casing (4) is moved into its protecting position beyond said zone and in that said tool or instrument (1) is uncovered when moving or just before moving said assembly in the opposite direction and before reaching said zone again.

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