FIELD OF THE INVENTION

The present invention relates to a completion release device for releasing an upper section of a completion system from a lower section of the completion system while cutting the external control lines.

BACKGROUND OF THE INVENTION

After the drilling of an oil and/or gas well, the well is completed before the production or injection of oil and/or gas/water can start. The completion operation involves installation of a completion system comprising production tubing and other downhole equipment in order to establish required barriers and optimize production or injection.

A production packer is used to seal the annular space between the production tubing and casing string. The completion system may also comprise a Polished Bore Receptacle (PBR), back-off sub and/or anchor separation sub to provide a possibility to separate and release the production tubing at predetermined location above the production/injection packer.

Control lines may also be provided from the topside to lower parts of the well. A control line may be electrical, hydraulic, fiber optic etc and is typically used to transfer electric and hydraulic power and/or electric, hydraulic and optic signals respectively. The control lines are used during the completion installation and production/ injection process in order to control or transfer signals to or from downhole completion tools.

During the split and release of the production tubing with external control line, the control line should also be cut to prevent entanglement of the control line, and hence to avoid extra operations for removing or retrieving residual control lines etc.

Cutting tools may be used to release the production/ injection tubing. Such cutting tools typically require use of wireline equipment. This type of operation is demanding with regards operation, personnel and equipment and has a considerable negative contribution to time, costs and risk. In most cases the external control line is not cut when cutting the production tubing, leaving the control line to be randomly separated when pulling the completion string.

The object of the invention is to provide a completion release device for releasing an upper part of a completion from the lower part of the completion in a reliable way. Another object is to provide a completion release device which also performs cutting of the control line. The releasing and cutting operation should be performed in a cost-efficient way, preferably without the need for cutting tools.

Another purpose is to provide that the control lines are sealed off during the cutting process. For hydraulic control lines, this is a preferred solution. Yet another purpose of the invention is to provide a possibility for connection of a new completion system to the remaining parts of the previous lower completion system after release and retrieval of the previous completion.

SUMMARY OF THE INVENTION

The present invention relates to a completion release device for releasing the completion in an oil and/or gas well. The completion release device is comprising:

- a mandrel device comprising an upper mandrel section and a lower mandrel section;

- a housing device provided radially outside the mandrel device; where a control line compartment is provided in an axial direction outside of the mandrel device and inside of the housing device; where:

- the mandrel device is provided as one body;

- the mandrel device comprises a weak area provided between the upper mandrel section and the lower mandrel section; - the mandrel device comprises a radial protrusion provided above the weak area;

- the device further comprises a control line cutting mechanism provided adjacent to the control line compartment, where the control line cutting mechanism is configured to be actuated by axial movement of the radial protrusion.

The purpose of the weak area is to define a predetermined area of the mandrel device where the mandrel device is configured to be separated. Accordingly, the mandrel device is configured to be separated at the weak area when the first and second mandrel sections are pulled away from each other with a predetermined pulling force.

In one aspect, the weak area comprises one or several recesses provided

circumferentially in the inner or outer surface of the mandrel device.

In one aspect, the control line cutting mechanism comprises a cutting body, where the cutting body is configured to be displaced radially out towards the housing device when actuated by the radial protrusion. In one aspect, the cutting body comprises a cutting area for cutting a control line provided in the control line compartment.

In one aspect, the cutting body comprises a compression area for compressing an upper end of a lower section of the control line.

In one aspect, the cutting mechanism comprises a collet provided radially outside of the mandrel device, where the collet is connected to the cutting body via a flexible finger member.

In one aspect, the device comprises a sleeve device provided radially outside of the mandrel device and axially above and below the weak area.

In one aspect, the housing device comprises an upper opening with a connection device for connection to a further re-completion system.

In one aspect, the connection device comprises a ratchet mechanism.

In one aspect, the mandrel device comprises a cutting zone.

In one aspect, the sleeve device comprises a fluid circulation port provided below the weak area for allowing fluid flow between the inside of the mandrel device and the outside of the device 1 after separation of the mandrel device.

In one aspect, the device comprises a no-go mechanism for reducing compression forces on the lower mandrel section.

DETAILED DESCRIPTION

Embodiments of the invention will now be described in detail with reference to the enclosed drawings, where:

Fig. 1 illustrates a side view of a first embodiment;

Fig. 2 illustrates a cross sectional view of the first embodiment; Fig. 3 illustrates a perspective view of the mandrel device;

Fig. 4 illustrates a perspective view of the collet fingers provided outside of the mandrel device;

Fig. 5 illustrates a perspective view of the collet fingers and sleeve device provided on the mandrel device; Fig. 6 illustrates an enlarged cross sectional view of the control line cutting mechanism in the initial state; Fig. 7 illustrates an enlarged cross sectional view of the control line cutting mechanism during cutting of the control line;

Fig. 8 illustrates a perspective view of the control line cutting mechanism during cutting of the control line; Fig. 9 illustrates an enlarged cross sectional view of an alternative embodiment of the control line cutting mechanism, where the end of the cut control line is compressed and sealed off;

Fig. 10 illustrates a perspective view of the retrieval of the upper section of the completion system from the lower section of the completion system; Fig. 11 illustrates a perspective view of a new upper completion system being lowered into and connected to the completion release device;

Fig. 12 illustrates a cross sectional perspective view of the completion release device after the reconnection of the new upper completion system;

Fig. 13 illustrates a cross sectional view of a second embodiment; Fig. 14 illustrates the upper part of the second embodiment;

Fig. 15 illustrates the lower part of the second embodiment after retrieval;

Fig. 16 illustrates the control line cutting mechanism of a third embodiment before cutting;

Fig. 17 illustrates the control line cutting mechanism of the third embodiment after cutting;

Fig. 18 illustrates a cross sectional view of the cutting mechanism of a fourth embodiment, before cutting of the control line;

Fig. 19 illustrates a cross sectional view of the cutting mechanism of the fourth embodiment, after cutting of the control line.

It is now referred to fig. 1 and 2. Here, a first embodiment of the completion release device 1 is shown. The completion release device 10 is used in an oil and/or gas well for releasing an upper section of a completion system from a lower section of the completion system. In the following, it should be noted that terms like "upper" etc. are used to describe elements facing towards the topside of the well, while the terms "lower" etc. are used to describe elements facing towards the bottom of the well. The completion release device 1 comprises a mandrel device 10 and a housing device 20. In its upper end, the device 1 is provided with a connection interface for connection to upper production tubing (not shown), and in its lower end, the device 1 is provided with a connection interface for connection to lower production tubing. In fig. 1 and 2, a part of the lower production tubing is indicated with reference number 2.

The mandrel device 10 is provided as one tubular body with a through bore 19. The mandrel device 10 comprises a weak area 1 1 provided between an upper mandrel section 10a and a lower mandrel section 10b, i.e. the weak area 11 defines the border between the lower and upper sections 10a, 10b. In the present invention, the mandrel device 10 comprises the connection interfaces for the upper and lower production tubes. In the drawings, the upper side of the device 1 is shown to the left, while the lower side of the device 1 is shown to the right.

The mandrel device 10 is configured to be separated at the weak area 11 when the first and second mandrel sections 10a, 10b are pulled away from each other with a predetermined pulling force. In the present embodiment, the weak area 1 1 comprises one continuous recess provided circumferentially in the outer surface of the mandrel device 10. Alternatively, the recess could be discontinuous, i.e. provide as several recesses spaced apart circumferentially in the outer surface of the mandrel device. In yet another alternative, the one recess or the several recesses could be provided in the inner surface of the mandrel device 10.

In fig. 2, 3 and 6 it is shown that the mandrel device 10 further comprises a radial protrusion 12. The protrusion 12 is provided above, i.e. on the upper side of, the weak area 1 1. In the present embodiment, the protrusion 12 is provided as a part of the mandrel device itself. However, it is possible to provide the protrusion 12 as a separate part fixed outside the mandrel device, for example by means of shear pins. Hence, if something fails, and the radial protrusion 12 is stuck within the housing device 20, it is still possible to pull the mandrel device 10 out from the well.

The housing device 20 is provided radially outside the mandrel device 10. A control line compartment 21 is provided in an axial direction outside of the mandrel device 10 and inside of the housing device 20. In fig. 1 and 2, a control line is indicated by reference number 3. The control line 3 is provided on the outside of the production tubing 2 and outside of the mandrel device 10, and is guided through the control line compartment 21 on the inside of the housing device 20, as indicated in fig. 2. The housing device 20 comprises an upwardly facing opening indicated by reference number 22 in in fig. 10 and 11. The mandrel device 10 comprises a centering member 15 for centering the mandrel device 10 in relation to the opening in the outer housing 20. The housing device 20 further comprises a connection device 23 for connection to a further re-completion system. In the present embodiment, the connection device 23 is a ratchet mechanism for connection to a corresponding ratchet mechanism 123 of the further re-completion system, which will be described below.

It should be noted that the completion system may comprise one or more control lines. In fig. 1 and 2 four control lines 3 are indicated, in fig. 10 six control lines are shown.

It is now referred to fig. 6. Here, it is shown that the device 1 comprises a control line cutting mechanism generally indicated by arrow 40. The control line cutting mechanism is provided adjacent to the control line compartment 21, and is actuated by axial movement of the radial protrusion 12.

In fig. 6, the cutting mechanism 40 comprises a cutting body 41, where the cutting body 41 is configured to be displaced radially out towards the housing device 20 when actuated by the radial protrusion 12, i.e. as the radial protrusion 12 is moved axially upwardly until the radial protrusion 12 is provided radially inside of, or as shown in fig. 6, under, the cutting body 41. As shown in fig. 6 and 7, the cutting body 41 and radial protrusion 12 each have inclining areas to simplify the radial movement of the cutting body 41.

The cutting body 41 is also shown in fig. 4. Here, the cutting body 41 is provided radially outside the mandrel device 10. The cutting body 41 is connected to a flexible finger member 45, which again is connected to a collet 44 provided radially outside of the mandrel device 10. In this way, the cutting body 41 is held in the correct position in relation to the control line compartment 21 (and hence the control line 3). Moreover, as is indicated in fig. 4, several cutting bodies 41 can be held in their respective correct positions by connecting them via respective finger members 45 to one common collar 44. '

The finger member 45 ensures that the cutting body 41 is held at its axial position in relation to the collar 44, but allows that the cutting body 41 is displaced radially outwards by the protrusion 12.

To further position the cutting body 41 correctly in relation to the control line compartment 21, the radial protrusion 12 may comprise a guiding recess 13, as indicated in fig. 3. The guiding recess 13 guides the cutting body 41 when the mandrel device 10 is displaced in relation to the outer housing in an axial direction, as will be described further in detail below.

The collar 44, the finger member 45 and the cutting body 41 is held in their axial positions in relation to the outer housing 20. The collar 44 could for example be fixed directly to the inside of the outer housing 20. In the present embodiment, the device 1 comprises a sleeve device 30 provided radially outside of the mandrel device 10 and axially above and below the weak area 11. Hence, one purpose of the sleeve device 30 is to support the mandrel device 10 in the area near the weak area 11, to prevent bending of the mandrel device etc. In fig. 6 it is indicated that the sleeve device 30 comprises a section 32 with additional thickness as a reinforcement of the weak area 11 of the mandrel device.

Another purpose of the sleeve device 30 is to support the cutting mechanism 40 in relation to the housing device 20. In fig. 2 and 5, it is shown that the sleeve device 30 is provided radially outside of the lower section 10b of the mandrel device 10 and is provided radially inside of the collar 44 and the flexible fingers 45. The sleeve device 30 comprises a radial opening 31 , where the opening 31 is forming a compartment for the cutting body 41. The opening 31 in the sleeve device 30 is best shown in fig. 8.

In fig. 6, it is shown that the cutting body 41 may comprise a cutting area 42 for cutting the control line 3 provided in the control line compartment 21. As shown in fig. 6, the control line compartment 21 may comprise a first, narrow compartment section 21a and a second, wider compartment section 21b radially outside of the cutting body 41. Hence, the cutting area 42 may then be configured to cut the control line 3 by pressing the control line radially outwards and away from the opening into the narrow compartment section 21a, as indicated in fig. 7. Here, it also is achieved that the upper end of a lower section 3b of the control line 3 is compressed, in order to prevent or at least limit leakage of fluid in the control line (in case of an hydraulic control line).

Alternatively, the cutting area 42 is sharpened and cuts the control line 3 like a knife. Yet another alternative is to compress the control line 3 below the cutting area prior to cutting.

In fig. 9, an alternative embodiment is shown. Here, the cutting body 41 comprises a compression area 43. Here, the cutting area 42 cuts the control line 3 as described above. In addition, the compression area 43 compresses the upper end of a lower section 3b of the control line 3. In this way, fluid in the lower section of the control line will not leak out from the control line, or at least the leakage is limited. In fig. 9, the cutting area 43 compresses the fluid line 3 against the surface of a narrower compartment section 21a.

In addition, the device 1 comprises a no-go mechanism. The no-go mechanism comprises an inwardly protruding collar 28 in the opening 22 of the housing device 20, as shown in fig. 2 and 12, and an outwardly protruding collar 18 on the outside of the mandrel device 10. The purpose of the no-go mechanism is to reduce or prevent that compression forces is applied to the lower mandrel section 10a. The mandrel device 10 further comprises a cutting zone indicated as CZ in fig. 2. The cutting zone CZ is defined as the area of the mandrel device below the protrusion 12, i.e. the area below the protrusion 12 and down to the upper end of the lower production tubing 2. The cutting zone CZ is a contingency cut-to-release zone which, if required, allows the inner mandrel to be cut with an intervened cutting tool in case the release by means of the weak area do not work as expected. It should be noted that the cutting zone CZ is provided below the collar 12, i.e. the cutting zone CZ is provided in an area of the mandrel device 10 in which there are no compressive forces on the mandrel device 10, a preferred situation during cutting of a mandrel. In the present embodiment, the cutting zone CZ is 30 cm. The sleeve device 30 may comprise one or more circulation ports 33, allowing fluid to circulate between the bore 19 and the outside of the device 1 after the release of the upper section of the mandrel device or after cutting of the mandrel device in the cutting zone CZ. The release of the completion release device will now be described with reference to fig. 6, 7 and 8. In fig. 1, the initial state is shown. When a release is desired, a tension or pulling force is applied to the upper end of the mandrel device 10. When a predetermined threshold force is achieved (for example 70 - 150 metric tons), the weak area 11 yields and a separation between the upper and lower sections 10a, 10b of the mandrel device 10 is achieved, as shown in fig. 7.

The upper section 10a is pulled further upwards. As shown in fig. 7, the protrusion 12 will press the locking body 41 of the locking mechanism 40 radially outwards and the control line 3 will be cut into an upper control line 3a and a lower control line 3b. Preferably, there is a distance La (shown in fig. 6) between the protrusion 12 and the cutting body 41 in order to create impact due to upper completion stretch and stress release when the weak area 1 1 is separated. Consequently, the control line 3 is cut after the yield or separation of the weak area 11.

Hence, separation of the mandrel device 10 may be achieved in two ways - either at the weak area 11 by applying a pulling force to the upper section of the mandrel device 10 or in the cutting zone CZ by using a cutting tool.

After the cutting of the control line 3, the upper part of the completion system can be retrieved out from the housing device 20, as shown in fig. 10. A new upper completion system can now be lowered, as shown in fig. 1 1, where the new upper completion system is generally referred to with reference number 100.

The new upper completion system 100 comprises a new upper mandrel section 110a, which, similar to the previous upper mandrel section 10a, comprises a through bore 119, a no-go collar 118 and a centering member 115. The lower end 1 11 of the new upper mandrel section 110a is configured to be provided adjacent to the upper end (i.e. in the area of the separation of the weak area 11) of the lower mandrel section 10b providing a smooth interface with equal inner diameters and limited recess between the new upper mandrel section 110a and the previous upper mandrel section 10b. The cutting mechanism 40 and control lines 3b are isolated with the new upper mandrel section 110a being stung past the cutting mechanism 40 and adjacent to the lower mandrel section 10b. In addition, the new upper mandrel section 1 10a comprises a locking mechanism 123 for locking to the connection mechanism 23 of the outer housing 20, as shown in fig. 12. The new locking mechanism 123 also comprises an emergency release ring 124, which can be sheared at a predetermined force allowing the locking mechanism 123 to be collapsed and the new upper mandrel section 110a to be retrieved.

As mentioned above, the locking mechanism 123 of the present embodiment is a ratchet mechanism for locking into the connection mechanism 23. It is now referred to fig. 13, 14 and 15, where a second embodiment is shown. Parts with same design and/or function as the first embodiment have same reference numbers as the first embodiment. As indicated, the well tool device 1 also here comprises a mandrel device 10 and a housing device 20 with similar structure and function as the first embodiment. It should be noted that in this embodiment, no sleeve device is present. Here, the centering member 15 is fixed to the housing device 20 with shear pins. Also the control line cutting mechanism 40 here comprises a cutting body held axially between the centering member and the housing device 20. The mandrel device 10 is separated via the weak area 1 1 and the radial protrusion 12 is activating the cutting mechanism 40 as the radial protrusion 12 is moved axially upwards, similar to the first embodiment. The dashed line in fig. 14 is indicating the separation between the upper and lower mandrel sections 10a, 10b. However, during the separation and the cutting operation, the centering member 15 is held stationary with respect to the housing device 20. After the separation and cutting operation, the radial protrusion 12 is pulled further upwards with the upper mandrel section 10a, and the radial protrusion 12 engages an inner collar 15a of the centering member 15. A further pulling of the mandrel device 10 will shear the shear pins and the centering member 15 is released from the housing device 20 and can be retrieved from the well together with the mandrel device 10. It should be noted that in the second embodiment, the control line cutting mechanism 40 is retrieved from the well together with the mandrel device 10 and the centering member 15.

It is now referred to fig. 16 and 17, illustrating a third embodiment of a cutting mechanism. A radial protrusion 12 of the mandrel device 10 is indicated, as is also a part of a lower production pipe 2. The cutting mechanism 40 comprises an upper ring member 47 provided around the mandrel device 10 and a lower ring member 48 provided around the mandrel device 10. A control line compartment 21 is provided as axial recesses in the upper and lower ring members 47, 48. In fig. 16, the recesses are aligned with each other to form one linear control line compartment 21.

The upper ring member 47 comprises an horseshoe-shaped or elliptic end surface 47a faced towards the lower ring member 48 and the lower ring member 48 comprises an inverted horseshoe-shaped or elliptic end surface 48a faced towards the upper ring member 47. In the present embodiment, the upper ring member 47 is fixed to the housing device (not shown) by means of locking pins.

When the mandrel device 10 has been separated, the radial protrusion 12 moves upwards, moving the lower ring member 48 towards the upper ring member 47. Due to the opposite end surfaces 47a, 48a, the lower ring 48 will turn as indicated in fig. 17, and thereby cut the control line. As shown in fig. 17, the recesses forming the control line compartment 21 are no longer linear.

It is now referred to fig. 18 and 19. Here, the cutting body 41 comprises a control line compartment 49 aligned with the control line compartment 21 of the housing device 20, as shown in fig. 18. When the radial protrusion 12 of the mandrel device 10 is pulled upwardly, similar to the above embodiments, the cutting body 41 will be pressed radially outwards, and the control line compartment 49 of the cutting body 41 is no longer aligned with the control line compartment 21 of the housing device 20. This movement will cause cutting of the control line 3 as indicated in fig. 19. This embodiment will provide that the housing device 20 may have a smaller outer diameter than the embodiment in fig. 1 and 2.