Perforating apparatus

Abstract

An apparatus comprises perforating guns, bypass, and isolator mechanism. The first gun fires upon receipt of a first pressure signal delivered from a first axial side of the first gun. The second perforating gun is mounted on a second axial side of the first perforating gun, and fires upon receipt of a second pressure signal delivered from the first axial side of the first perforating gun. The bypass extends from the first axial side of the first gun to the second gun for communicating the second pressure signal to the second gun. The isolator mechanism is configurable between a first configuration in which the bypass is isolated from receiving a pressure signal to the second perforating gun, and a second configuration in which the bypass is permitted to receive a pressure signal. The isolator mechanism is reconfigurable from the first to the second configuration after the first gun has fired.

Claims

1. A perforating apparatus, comprising: a first perforating gun configured to fire upon receipt of a first pressure signal delivered from a first axial side of the first perforating gun; a second perforating gun mounted on a second axial side of the first perforating gun and configured to fire upon receipt of a second pressure signal delivered from the first axial side of the first perforating gun; a bypass extending from the first axial side of the first perforating gun to the second perforating gun for communicating the second pressure signal to the second perforating gun; an isolator mechanism configurable between a first configuration in which the bypass is isolated from receiving a pressure signal to the second perforating gun, and a second configuration in which the bypass is permitted to receive a pressure signal; wherein the isolator mechanism is reconfigurable from the first configuration to the second configuration after the first perforating gun has been fired; and a flow diverter comprising a diversion path and an activation path, the flow diverter configured to selectively route the first pressure signal to the activation path under the action of a first activator to fire the first perforating gun.

2. The perforating apparatus according to claim 1, wherein the bypass extends from the first axial side of the first perforating gun to the second perforating gun externally of the first perforating gun.

3. The perforating apparatus according to claim 1, wherein the bypass extends through a non-firing zone defined by a charge or shot profile of the first perforating gun.

4. The perforating apparatus according to claim 3, wherein the bypass linearly or helically extends through the non-firing zone.

5. The perforating apparatus according to claim 3, wherein the charge or shot profile comprises a maximum number of eighteen charges or shots per foot.

6. The perforating apparatus according to claim 1, wherein the isolator mechanism comprises a moveable object that is movable in order to switch the isolator mechanism from the first configuration to the second configuration after the first perforating gun has been fired.

7. The perforating apparatus according to claim 6, wherein the moveable object comprises a receiving section configured to receive a reconfiguration activator, such that, when received, a second activator is configured to move the moveable object from the first configuration to the second configuration.

8. The perforating apparatus according to claim 7, wherein the first activator comprises a first ball or dart and the reconfiguration activator comprises a second ball or dart and a diameter of the first ball or dart is smaller than a diameter of the second ball or dart.

9. The perforating apparatus according to claim 6, wherein: the bypass is connected to a port of the isolator mechanism; and in the first configuration, the moveable object isolates the port from receiving a pressure signal to the bypass.

10. The perforating apparatus according to claim 1, wherein the isolator mechanism comprises a releasable connection configured to releasably secure the isolator mechanism in the first configuration.

11. The perforating apparatus according to claim 10, wherein the releasable connection is configured to be released when acted on by a pressure differential and/or force that is above a threshold so that the isolator mechanism transitions from the first configuration to the second configuration.

12. The perforating apparatus according to claim 1, wherein the isolator mechanism comprises a locking mechanism configured to lock the isolator mechanism in the second configuration.

13. The perforating apparatus according to claim 1, wherein the flow diverter is mounted on the first axial side of the first perforating gun.

14. The apparatus according to claim 1, wherein the bypass is supported by a clamp connected to the first perforating gun.

15. The perforating apparatus according to claim 1, further comprising a third perforating gun.

16. The perforating apparatus according to claim 15, wherein the second perforating gun is provided between the first perforating gun and the third perforating gun.

17. A method for operating a perforating apparatus, comprising: locating the perforating apparatus in a first position in a structure to be perforated; providing an isolator mechanism of the perforating apparatus in a first configuration; wherein in the first configuration, a bypass, extending from a first axial side of a first perforating gun to a second perforating gun mounted on a second axial side of the first perforating gun, is isolated from receiving a pressure signal to the second perforating gun; receiving a first activator in a flow diverter of the perforating apparatus, the flow diverter comprising a diversion path and an activation path; delivering a first pressure signal from the first axial side of the first perforating gun to the first perforating gun, wherein the first perforating gun is configured to fire upon receipt of the first pressure signal, and wherein the first pressure signal is selectively routed to the activation path of the flow diverter under the action of the first activator; relocating the perforating apparatus to a second position in the structure; reconfiguring the isolator mechanism to a second configuration, in which the bypass is permitted to receive a pressure signal to the second perforating gun; and delivering a second pressure signal from the first axial side of the first perforating gun to the second perforating gun, wherein the second perforating gun is configured to fire upon receipt of the second pressure signal.

18. The method according to claim 17, wherein the first perforating gun creates a first perforation in the structure and the second perforating gun creates a second perforation in the structure, the method further comprising injecting a circulation fluid into the first perforation and out of the second perforation.

19. A method of operating a perforating apparatus downhole, the perforating apparatus comprising at least a first perforating gun and a second perforating gun, the method comprising: locating the perforating apparatus in a first position downhole such that the first perforating gun is uphole of the second perforating gun; receiving a first activator in a flow diverter of the perforating apparatus, the flow diverter comprising a diversion path and an activation path; delivering a first pressure signal to the first perforating gun from the uphole side of the first perforating gun, wherein the first pressure signal is selectively routed to the activation path of the flow diverter under the action of the first activator, and wherein the first perforating gun is operable to perform a perforation operation responsive to the first pressure signal, to create a first perforation; after operation of the first perforating gun, relocating the perforating apparatus to a second position in the structure; and delivering a second pressure signal from the uphole side of the first perforating gun to the second perforating gun via a bypass that bypasses the first perforating gun, wherein the second perforating gun is configured to create a second perforation in the structure upon receipt of the second pressure signal.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) These and other aspects of the present disclosure will now be described, by way of example only, with reference to the accompanying drawings, in which:

(2) FIG. 1 is a diagrammatic illustration of a perforating apparatus, in use, and located in a wellbore;

(3) FIG. 2 is a cross-sectional view of an isolator mechanism and a flow diverter of the perforating apparatus, wherein the isolator mechanism is in a first configuration;

(4) FIG. 3 is a cross-sectional view of the isolator mechanism and the flow diverter with a first activator received by the flow diverter;

(5) FIG. 4 is a diagrammatic illustration of a first stage of an example application of the perforating apparatus;

(6) FIG. 5 is a diagrammatic illustration of a scallop or shot profile of the first perforating gun with a bypass linearly extending from a first axial side of the first perforating gun to the second perforating gun;

(7) FIG. 6 is a diagrammatic illustration of the scallop or shot profile of the first perforating gun with an alternative bypass helically extending around the first perforating gun;

(8) FIG. 7 is a diagrammatic illustration of an example clamp supporting the bypass;

(9) FIG. 8 is cross-sectional view of the clamp of FIG. 7 taken along line X-X;

(10) FIG. 9 is a diagrammatic illustration of a second stage of the example application of the perforating apparatus;

(11) FIG. 10 is a cross-sectional view of the isolator mechanism and the flow diverter with a second activator received by the isolator mechanism, wherein the isolator mechanism is in the first configuration;

(12) FIG. 11 is a cross-sectional view of the isolator mechanism and the flow diverter with the second activator received by the isolator mechanism, wherein the isolator mechanism is in the second configuration;

(13) FIG. 12 is a diagrammatic illustration of a third stage of the example application of the perforating apparatus;

(14) FIG. 13 is a diagrammatic illustration of a fourth stage of the example application of the perforating apparatus;

(15) FIG. 14 is a diagrammatic illustration of a first stage of an alternative example application of the perforating apparatus;

(16) FIG. 15 is a diagrammatic illustration of a second stage of the alternative example application.

DETAILED DESCRIPTION OF THE DRAWINGS

(17) The present disclosure relates to a perforating apparatus which may be utilized for a variety of applications. In the description that follows, example forms of the perforating apparatus are presented, without any intended restriction on a specific application or use, although some examples of potential operations that could be performed using the perforating apparatus will be suggested, and one specific example use of the apparatus will be provided.

(18) A diagrammatic illustration of the perforating apparatus, generally identified by reference numeral 10, deployed in a wellbore 12 is shown in FIG. 1. While the perforating apparatus 10 may be used in a wide range of applications, this example shows the perforating apparatus used in a wellbore application. Therefore, in this case, the perforating apparatus 10 defines an outer diameter and form which permits suitable downhole deployment and operation. For example, the perforating apparatus 10 could be cylindrical, although this is not essential.

(19) As shown, the perforating apparatus 10 is run into the wellbore 12 by a tubing string 14 to which the perforating apparatus 10 is mounted. In this example, a first axial side (e.g. an uphole side in use) of the perforating apparatus 10 is mounted to the tubing string 14. A pressure signal may be communicated to the apparatus 10 from a pump (not shown) or other pressure controlling apparatus, which could for example be located at the surface, via the tubing string 14. As can be seen, the perforating apparatus 10 is positioned in the wellbore 12 at a location close to a wellhead area, which includes a well-control system 16. The perforating apparatus 10 includes a first perforating gun 18 and a second perforating gun 20. The second perforating gun 20 is mounted on a second axial side (e.g. a downhole side in use) of the first perforating gun 18.

(20) The perforating apparatus 10 includes a bypass 22. The bypass 22 is connected at its first end 24 on the first axial (e.g. uphole) side of the first perforating gun 18, and extends from the first axial side of the first perforating gun 18 to the second perforating gun 20, to which the bypass 22 is connected at its second end 26. In this way, the bypass 22 effectively bypasses the first perforating gun 18. This enables a pressure signal to be delivered to the second perforating gun 20 from the first axial side of the first perforating gun 18. As can be seen, the bypass 22 extends externally of the first perforating gun 18. The bypass 22 is located between trajectories of the charges of the first perforating gun 18, as is discussed in more detail below.

(21) The apparatus 10 includes an isolator mechanism and a flow diverter, which are generally indicated together by reference numeral 28. FIG. 2 shows an enlarged cross-sectional view of the isolator mechanism 30 and flow diverter 32. In the shown example, the isolator mechanism 30 is connected to the flow diverter 32 via threaded sections 34 and 36. The isolator mechanism 30 is provided with a further threaded section 38, which, for example, may be used to connect the apparatus 10 to the tubing string 14. The flow diverter 32 is provided with a flat-ended surface 37. The surface 37 may be configured to engage or connect with the first perforating gun 18. While threaded connections have been used in this example, the skilled person will appreciate that alternative connections may be used, such as interference fits, fasteners, etc.

(22) The bypass 22 is connected at its first end 24 to a port 39 located on a side face of the isolator mechanism 30. In this example, the bypass 22 is threadably connected to the port 39. However, alternative connections may be used, such as an interference fit, etc.

(23) The isolator mechanism 30 includes a body 41 defining a passageway 43 configured to permit a pressure signal to pass therethrough. The passageway 43 is located centrally in the isolator mechanism 30.

(24) The isolator mechanism 30 includes a moveable object, which, in this example, is a slideable sleeve 40. The slideable sleeve 40 includes an opening 45 configured to permit a pressure signal to pass therethrough. FIG. 2 shows the isolator mechanism 30 in a first configuration in which the isolator mechanism 30 blocks the port 39 so as to prevent pressure signals received by the isolator mechanism 30, e.g. from the tubing string 14, from being passed to the bypass 22. In this first configuration of the isolator mechanism 30, the slideable sleeve 40 is positioned so as to isolate the bypass 22 from receiving pressure signals from within the isolator mechanism 30 (e.g. from within the opening 45). The isolator mechanism 30 is provided with seals 47 and 49 that are configured to seal between the slidable sleeve 40 and an interior wall of the body 41 that defines the passageway 43 to assist in isolating the bypass 22 from receiving pressure signals when the isolator mechanism 30 is in the first configuration. The slideable sleeve 40 includes a receiving section 35 on an uphole/surface side thereof, the receiving section 35 being configured to receive a second activator, which is discussed in more detail below. In this example, the receiving section 35 is inwardly tapered or otherwise shaped in order to securely receive the second activator. While a slideable sleeve has been shown in this example, the skilled person will appreciate, however, that alternative moveable objects may also be used, such as a gate, etc.

(25) The isolator mechanism 30 further defines a first recess 42 including an oblique surface (not shown). In the first configuration, the slideable sleeve 40 is releasably secured to the first recess 42 by way of a releasable connection therewith. In this example, the releasable connection includes a locking ring 44 configured to releasably connect with the first recess 42, in the first configuration. The locking ring 44 is radially outwardly biased such that it is forced into contact with the first recess 42 when the isolator mechanism 30 is in the first configuration. The skilled person will appreciate, however, that the releasable connection may instead comprise any other suitable means, such as a shear pin, ratchet, spring, adhesive, etc.

(26) The isolator mechanism 30 further defines a second recess 46. The second recess 46 is positioned axially away from the first recess 42 in a direction towards the flow diverter 32. The second recess 46 includes a shoulder 48 configured to engage the locking ring 44, when the isolator mechanism 30 is in the second configuration, such that the slidable sleeve 40 is locked in position relative to the body 41 of the isolator mechanism 30. As such, in the second configuration of the isolator mechanism 30, the slideable sleeve 40 is removed from the port 39 and the bypass 22 is permitted to receive a pressure signal for the second perforating gun 20.

(27) The flow diverter 32 includes a diversion path 51 configured to divert flow away from the first perforating gun 20. The diversion path 51 includes a diversion inlet 54, which is placed centrally within the flow diverter 32. The diversion path 51 includes a tapered section 56, which is tapered inwardly as it extends in a direction generally away from the diversion inlet 54 and towards a diversion outlet. In this example, the diversion outlet includes three circumferentially spaced outlet ports 58, which are located on an external, side face of the flow diverter 32, and are arranged symmetrically so that a balanced reaction force may act on the flow diverter 32. The flow diverter 32 thus enables a pressure signal or other flow to be initially circulated through the apparatus 10, if desired, without the first perforating gun 18 or second perforating gun 20 being fired.

(28) The flow diverter 32 also includes an activation path 52 configured to deliver a pressure signal to the first perforating gun 18. The activation path 52 includes an activation inlet 60 and an activation outlet 62. The activation path 52 is placed eccentrically within the flow diverter 32. Furthermore, the activation inlet 60 has a diameter smaller than a diameter of the diversion inlet 54. Consequently, a higher flow rate may initially pass through the diversion path than the activation path. In this example, the activation path 52 includes three circumferentially spaced channels that each linearly extend from their respective inlets 60 to their respective outlets 62. The activation paths 52 run parallel to at least part of the diversion path 51.

(29) FIGS. 3 and 4 depict a first stage of an example application of the perforating apparatus 10. Specifically, the example application relates to a well-decommissioning application involving the recovery of an oil-based mud 68 trapped in an annulus 67 between a casing 66 and the wellbore 12.

(30) Referring specifically to FIG. 3, there is shown a cross-sectional view of the isolator mechanism 30 in its first configuration, as well as the flow diverter 32 with a first activator 64 received by the tapered section 56 of the diversion path 51. In this example, the first activator 64 is a drop ball. However, the skilled person will appreciate that alternative activators may be used, such as a dart, etc.

(31) As can be seen in FIG. 3, the isolator mechanism 30 is in its first configuration with the slideable sleeve 40 isolating the bypass 22 from receiving a pressure signal, for example, from the tubing string 14. As such, the second perforating gun 20 is isolated from receiving a pressure signal.

(32) As noted above, the ball 64 is landed on the tapered section 56 of the flow diverter 32, for example, by dropping the ball 64 from the surface through the tubing string 14 and passageway 43. Thus, with the ball 64 received, flow being communicated from the tubing string 14 is blocked from entering the diversion path 51. As such, flow can no longer exit the apparatus 10 through the outlet ports 58, and consequently hydraulic pressure is increased in the activation path 52. This increase in pressure may function to deliver the first pressure signal to the first perforating gun 18, e.g. by increasing the pressure in the activation path 52 above a pressure threshold.

(33) FIG. 4 shows a diagrammatic illustration of the perforating apparatus 10 in a first position in the wellbore 12. As shown, the first perforating gun 18 has been fired, by way of the above-described procedure, and a first set of perforations 69 has been created in the wellbore 12 positioned just below the well-control system 16.

(34) It is worth noting, with reference to FIG. 4, that if the second perforating gun 20 had to be fired first, the first perforating gun 18 would be axially aligned with the well-control system 16 at the time of firing the second gun 20. As previously discussed, such an operation would have the potential to pose a risk to the well-control system. As such, being able to fire the first perforating gun 18 (i.e. an uphole perforating gun) before firing the second perforating gun (i.e. a downhole perforating gun) may be particularly beneficial in such “near surface” operations.

(35) Referring now to FIGS. 5 and 6, there is shown a scallop or shot profile of the first perforating gun 18, which is defined by a plurality of scallops or shots 70. As can be seen, the bypass 22 extends through a non-firing zone of the shot profile. The non-firing zone may be identified as an area of the scallop or shot profile in which no charges or shots 70 are fired. FIG. 5 shows an example bypass 22 which extends linearly across the first perforating gun 18, between charges or shots 70 of the first perforating gun 18, towards the second perforating gun 20. FIG. 6 shows an alternative bypass 22b which extends helically around the first perforating gun 18 and between charges or shots 70 of the first perforating gun 18, which are also arranged in a generally helical distribution.

(36) FIG. 7 shows a clamp 72 configured to provide structural support to the bypass 22. The clamp 72 is secured by a lock 74 to a section of the first perforating gun 18 in which no scallops or shots are present. The skilled person will appreciate, however, that while a rectangular lock 74 has been shown in FIG. 7, any suitable lock may be used, such as a tapered lock. FIG. 8 shows a cross-sectional view of the clamp 72 taken along dashed line X-X in FIG. 7. The clamp 72 includes an aperture 73 for locating the bypass 22 therein. The clamp 72 may include a plurality of apertures 73 for supporting a plurality of bypasses 22, if desired. As can be seen, the clamp 72 is eccentrically mounted on the first perforating gun 18, such that the clamp is provided with a larger radial thickness at the side of the clamp 72 including the apertures 73 and lock 74.

(37) FIGS. 9 and 10 depict a second stage of the example application of the perforating apparatus 10. Specifically, FIG. 9 shows a diagrammatic illustration of the perforating apparatus 10 moved to a second position in the wellbore 12. FIG. 10 shows a second activator 76 received by the receiving section 35 of the slideable sleeve 40. In this example, the second activator 76 is a drop ball. However, the skilled person will appreciate that alternative activators may be used, such as a dart, etc.

(38) When the receiving section 35 of the slideable sleeve 40 has received the second activator 76, a substantial seal is formed therebetween, thus flow being communicated from the tubing string 14 can no longer enter the passageway 43 of the isolator mechanism 30. Instead, pressure is built up behind the second activator 76 causing a pressure differential between the interior of the tubing string 14 and the passageway 43 of the isolator mechanism 30, resulting in a force acting on the slideable sleeve 40. Once a predetermined force is reached, the locking ring 44 is configured to disengage the first recess 42. This may be achieved, for example, by selecting a material and thickness of the locking ring 44 that is configured to sufficiently deform at the predetermined force so that the locking ring 44 is able to slide across the oblique surface of the first recess 42 and release the releasable connection.

(39) Referring now to FIG. 11, there is shown a third stage of the example application of the perforating apparatus 10. The isolator mechanism 32 is shown in its second configuration and as such the slideable sleeve 40 has moved through the passageway 43 towards the second recess 46, and thus away from the port 39. Consequently, the bypass 22 is permitted to receive a pressure signal through the port 39. Thus, as the slideable sleeve 40 slides towards the second recess 46, the second perforating gun 20 is permitted to receive the second pressure signal.

(40) To prevent the isolator mechanism 30 transitioning back to the first configuration, and thus the slideable sleeve 40 sliding back towards the first recess 42, the second recess 46 is provided with a right-angled surface, or shoulder. As the slideable sleeve 40 reaches the position shown in FIG. 11, the locking ring 44 radially expands into the second recess 46 by virtue of its radially outwardly bias. As a result, the second recess 46 engages the locking ring 44 and thereby locks it in place. In this respect, the locking ring 44 and the second recess 46 together may be defined as a locking mechanism. While a locking ring has been shown in this example, the skilled person will appreciate that alternative locking mechanisms may also be used, such as a swellable material, ratchet, adhesive, etc.

(41) FIG. 12 depicts a third stage of the example application of the perforating apparatus 10. As can be seen, the second perforating gun 20 has been fired, by way of the above-described procedure, and a second set of perforations 78 has been created in the wellbore 12, positioned below the first set of perforations 69.

(42) FIG. 13 depicts a fourth and final stage of the example application of the perforating apparatus 10. In this example, the perforating apparatus 10 has been removed from the wellbore 12 and a suitable injection tool 80 has been run into the wellbore 12. However, if desired, the perforating apparatus 10 may be provided with an on-board injection tool.

(43) The injection tool 80 is configured to inject a pressurized fluid, which is generally indicated by arrows 82, through the second set of perforations 78, into the annulus 67 and out of the first set of perforations 69. It will be appreciated that packers and the like can be used in order to direct the flow in the desired manner. As can be seen, the oil-based mud 68 is removed from the annulus 67 and transported towards the surface with the pressurized fluid 82.

(44) Referring now to FIGS. 14 and 15, there is shown an alternative example of the perforating apparatus 10. In this example, the perforating apparatus 10 includes a third perforating gun 84 mounted on a second axial side of the second perforating gun 20. The perforating apparatus 10 has been run deeper into the wellbore 12 by the tubing string 14 to reach a location in which it is desired to pressure test a naturally-formed seal 83. For example, the naturally-formed seal may exist between a rock formation 85 and an external surface of the wellbore 12. The naturally-formed seal 83 may be formed by the creep of the rock formation 85 towards the wellbore 12. For example, the rock formation 85 may comprise sedimentary rock, such as shale rock.

(45) In this alternative example application, the third gun 84 has been fired to create a third set of perforations 86 in the wellbore 12 at a position below the naturally-formed seal 83, such that a pressure signal, generally indicated by arrows 90, may be communicated through the third set of perforations 86 to test the sealing capability of the seal 83. The pressure signal may include hydraulics, acoustics, or any other suitable means.

(46) It should be understood that the examples provided herein are merely exemplary of the present disclosure and that various modifications may be made thereto without departing from the scope defined by the claims.