Title:
PERFORATING GUN ASSEMBLY
Kind Code:
A1


Abstract:
A perforating gun assembly including: an upper end; a perforating gun connected to the upper end; a hydraulically actuated tool connected to the perforating gun on an end opposite the upper end; and a fluid conduit extending through the upper end and to the hydraulically actuated tool, the fluid conduit allowing fluid communication past the perforating gun to the hydraulically actuated tool such that fluid can be communicated through the upper end to actuate the hydraulically actuated tool.



Inventors:
Mytopher, Terry Lee (Grand Prairie, CA)
Farnel, Joseph Melvin (Red Deer, CA)
Application Number:
12/204580
Publication Date:
03/04/2010
Filing Date:
09/04/2008
Assignee:
INTEGRATED PRODUCTION SERVICES LTD. (Calgary, CA)
Primary Class:
Other Classes:
166/55.2
International Classes:
E21B43/116
View Patent Images:
Related US Applications:



Primary Examiner:
BOMAR, THOMAS S
Attorney, Agent or Firm:
Bennett Jones, Llp C/o Ms Roseann Caldwell (4500 BANKERS HALL EAST, 855 - 2ND STREET, SW, CALGARY, AB, T2P 4K7, CA)
Claims:
We claim:

1. A perforating gun assembly comprising: an upper end; a perforating gun connected to the upper end; a hydraulically actuated tool connected to the perforating gun on an end opposite the upper end; and a fluid conduit extending through the upper end and to the hydraulically actuated tool, the fluid conduit allowing fluid communication past the perforating gun to the hydraulically actuated tool such that fluid can be communicated through the upper end to actuate the hydraulically actuated tool.

2. The perforating gun assembly of claim 1 wherein the upper end includes a connector for connecting the assembly to a tubing string

3. The perforating gun assembly of claim 1 wherein the upper end includes a connector for connecting the assembly to continuous tubing.

4. The perforating gun assembly of claim 1 further comprising a plug in the fluid conduit between the hydraulically actuated tool and the perforating gun such that the perforating gun is isolated from communication with fluid pressure communicated to actuate the hydraulically actuated tool.

5. The perforating gun assembly of claim 4 wherein the plug is openable.

6. The perforating gun assembly of claim 4 wherein the plug is a fixed wall.

7. The perforating gun assembly of claim 1 wherein the fluid conduit includes a bore passing through the upper end and a bypass line extending from a junction to the bore to the hydraulically actuated tool.

8. The perforating gun assembly of claim 7 further comprising a plug in the bore between the bore/by pass line junction and the perforating gun such that the perforating gun is isolated from communication with fluid pressure communicated to actuate the hydraulically actuated tool.

9. The perforating gun assembly of claim 7 wherein the bypass line extends externally along the perforating gun

10. The perforating gun assembly of claim 7 wherein the bypass line extends at least in part internally through the perforating gun.

11. The perforating gun assembly of claim 7 wherein the bypass line is positioned out of the explosive paths of any charges in the perforating gun.

12. The perforating gun assembly of claim 1 further comprising a check valve in the fluid conduit uphole of the bypass line.

13. The perforating gun assembly of claim 1 wherein the perforating gun is actuated hydraulically, mechanically or electrically.

14. The perforating gun assembly of claim 1 wherein the perforating gun is actuated by hydraulic pressure communicated through at least one of (a) the upper end and (b) an annulus about the perforating gun.

15. The perforating gun assembly of claim 1 further comprising a second perforating gun between the upper end and the hydraulically actuated tool.

16. The perforating gun assembly of claim 15 wherein the second perforating gun is actuated by system including a time delay mechanism.

17. The perforating gun assembly of claim 1 further comprising a fluid outlet sub operable to direct fluid from the perforating gun assembly into an annulus about the perforating gun assembly.

18. The perforating gun assembly of claim 1 further comprising a swivel.

19. The perforating gun assembly of claim 1 further comprising a centralizer.

20. The perforating gun assembly of claim 1 wherein the hydraulically actuated tool includes one or more of a packer, a plug, a shear mechanism, a time delay assembly and a perforating gun.

21. A method for perforating a well comprising: (a) providing a perforating gun assembly including an upper end, a perforating gun, a hydraulically actuated tool connected to the perforating gun on an end opposite the upper end and a fluid conduit extending through the upper end and to the hydraulically actuated tool, the fluid conduit providing a fluid path past the perforating gun to the hydraulically actuated tool; (b) running the perforating gun assembly to a position in a well; and (c) in any order (i) communicating fluid to the fluid conduit to actuate the hydraulically actuated tool; and (ii) actuating the perforating gun to perforate the well.

22. The method of claim 21 wherein running includes hanging the assembly on continuous tubing and moving the continuous tubing and assembly into the wellbore.

23. The method of claim 21 wherein actuating the perforating gun includes applying hydraulic pressure to the perforating gun's firing head.

24. The method of claim 21 wherein actuating the perforating gun includes a time delay.

25. The method of claim 21 wherein actuating the hydraulically actuated tool includes employing a pressure lower than that required when actuating the perforating gun.

26. The method of claim 21 further comprising moving an inoperable check valve into an operative position to control flow upwardly through the fluid conduit.

27. The method of claim 21 wherein the hydraulically actuated tool is a bridge plug and communicating fluid to the fluid expands an annular seal on the bridge plug to seal the well at the bridge plug.

28. The method of claim 21 further comprising circulating well treatment fluids from the perforating gun assembly into the well.

Description:

BACKGROUND

Perforating guns are used to access the formation behind a wellbore casing. In wellbore operations it is common to run into and out of a well a number of times to create isolated sections of the wellbore, perforate and treat the well. However, the increasing costs of well bore operations, including the rental rates for a rig and lost time, are urging operators to speed all wellbore service operations including those relating to wellbore perforating.

SUMMARY

In accordance with a broad aspect of the present invention there is provided a perforating gun assembly including an upper end, a perforating gun connected to the upper end, a hydraulically actuated tool connected to the perforating gun on an end opposite the upper end and a fluid conduit extending through the upper end and to the hydraulically actuated tool, the fluid conduit allowing fluid communication past the perforating gun to the hydraulically actuated tool such that fluid can be communicated through the upper end to actuate the hydraulically actuated tool.

In accordance with another broad aspect of the present invention, there is provided a method for perforating a well including: (a) providing a perforating gun assembly including an upper end, a perforating gun, a hydraulically actuated tool connected to the perforating gun on an end opposite the upper end and a fluid conduit extending through the upper end and to the hydraulically actuated tool, the fluid conduit providing a fluid path past the perforating gun to the hydraulically actuated tool; (b) running the perforating gun assembly to a position in a well; and (c) in any order (i) communicating fluid to he fluid conduit to actuate the hydraulically actuated tool; and (ii) actuating the perforating gun to perforate the well.

It is to be understood that other aspects of the present invention will become readily apparent to those skilled in the art from the following detailed description, wherein various embodiments of the invention are shown and described by way of illustration. As will be realized, the invention is capable for other and different embodiments and its several details are capable of modification in various other respects, all without departing from the spirit and scope of the present invention. Accordingly the drawings and detailed description are to be regarded as illustrative in nature and not as restrictive.

BRIEF DESCRIPTION OF THE DRAWINGS

Referring to the drawings wherein like reference numerals indicate similar parts throughout the several views, several aspects of the present invention are illustrated by way of example, and not by way of limitation, in detail in the figures, wherein:

FIG. 1 is an axial section through a wellbore with a perforating gun assembly positioned therein.

FIG. 2 is an axial section through another wellbore with another perforating gun assembly positioned therein.

FIG. 3 is an axial section through an upper junction of a perforating gun useful in a perforating gun assembly.

FIGS. 4a and 4b are axial sectional views through a check valve assembly useful in a perforating gun assembly.

DESCRIPTION OF VARIOUS EMBODIMENTS

The detailed description set forth below in connection with the appended drawings is intended as a description of various embodiments of the present invention and is not intended to represent the only embodiments contemplated by the inventor. The detailed description includes specific details for the purpose of providing a comprehensive understanding of the present invention. However, it will be apparent to those skilled in the art that the present invention may be practiced without these specific details.

A perforating gun assembly is proposed that includes a number of tools thereon including a perforating gun and enables an operator to both hydraulically actuate a tool below the perforating gun and fire the perforating gun to perforate the wellbore casing wall. In particular, the perforating gun assembly includes a bypass line that communicates hydraulic fluid from surface past the perforating gun to a tool located therebelow. The tool below the perforating gun can be one or more of a plug (drill out, retrievable, etc.), a packer, another perforating gun, a time delay assembly, a shear assembly, etc.

FIG. 1 shows one possible embodiment of a perforating gun assembly according to the present invention. The perforating gun assembly is intended to be run into and operated in a wellbore, as defined by wall 8, and includes an upper end including, for example, a connector 10 for connecting the assembly to a tubing string 12, such as one of continuous tubing, for example, coiled tubing as shown, and a tubing arrangement 14. A perforating gun 16 is connected to the upper end and a hydraulically actuated tool 18 is installed therebelow. Tool 18 is positioned on the other side of the perforating gun from the upper end, which in wellbore terminology would be considered downhole from the perforating gun.

Connector 10 and tubing arrangement 14 include at least partly therethrough a longitudinal bore 20 creating an inner diameter through which fluid can be received from the inner diameter of tubing string 12, as communicated from surface. Bore 20 may include a plug 22 permanently or releasably installed therein. Plug 22, if it is in place, blocks fluid communication to the perforating gun through the bore.

The assembly further includes a bypass line 24 extending from bore 20 to tool 18, acting as a conduit through which fluid can be communicated from the tubing arrangement to the tool to allow hydraulic actuation thereof. Bypass line 24 allows fluid to get past the perforating gun to be communicated to tool 18. In one embodiment, fluid conveyed through bore 20 can pass through bypass line 24 to reach the tool below the perforating gun. In some embodiments, when plug 22 is present, fluid may be communicated to tool 18, without also being communicated to perforating gun 16. In such an embodiment, bypass line 24 and plug 22 may isolate fluid from the perforating gun.

Connector 10 may take various forms depending on the form of tubing string intended to be used with the assembly and the downhole manipulation of the assembly which is sought to be achieved. For example, the assembly may conveniently be used with coiled tubing and, therefore in such an embodiment, a crossover connector suitable for connecting to coiled tubing may be employed.

Perforating gun 16 may take various forms depending on the wellbore conditions, the type of perforating job that is sought to be accomplished, operator preferences, etc. For example, perforating gun may be hydraulically, mechanically or electrically actuated to immediately detonate or after a time delay. For example, the gun may be actuated by a mechanical device, such as a ball, bar or dart dropped or otherwise conveyed from surface, an electrical device such as a wireline connected or downhole programmable logic controller, or hydraulically by various fluids and mechanisms.

Since the assembly is intended to facilitate hydraulic operations for tools to be actuated before or after the firing of the gun, it may be useful to also select a hydraulically actuated perforating gun. Such a gun may be actuated by hydraulic pressure in the annulus 27 about the gun or by through tubing pressures. In the illustrated embodiment of FIG. 1, perforating gun 16 is selected to be hydraulically actuated by annulus pressure. As such, perforating gun 16 includes an upper gun sub 28 including a pressure activated firing head 30 and a ported wall sub 32 through which annular pressure is communicated to firing head 30. Ports 34 in sub 32 allow fluid from the annulus about the tool assembly to be communicated to a chamber 36 of the sub and therethrough to a piston face 37 of firing head 30 positioned therein. Ports 34 may be removably closed by frangible members, such as glass, to protect against the entry of debris into chamber 36. Of course, if a gun is used that is actuated by tubing pressure, ported sub 32 may not be required as actuating pressure will be conveyed through bore 20 to the piston face, once flow past the plug in bore 20, such as by use of a removable or openable form of plug 22, is achieved.

Perforating gun 16, in the illustrated embodiment, further includes a charge tube in a housing sleeve 38, which is the outer perforated sleeve shown in the drawing. The charges installed along the charge tube are detonated by hydraulic operation of firing head 30.

As noted, perforating gun 16 can take various forms and configurations. As shown in FIG. 2, for example, a plurality of guns 116 can be used with or without time delay mechanisms for one or more of the guns. Although four guns 116a, 116b, 116c, 116d are shown, any number of guns can be used, as obviously limited by size and operational constraints. In the illustrated embodiment, uppermost gun 116a is detonated by a firing head 130 actuated, in this illustration, only by through tubing hydraulic pressure communicated through bore 120. Each of guns II 6b, 116c, 116d are installed with a time delay detonator 139b, 139c, 139d which is actuated by gas pressure generated from the perforating gun installed adjacent thereto. For example, the pressure shock generated by the detonation of gun 116a may act on time delay detonator 139b that causes gun 116b to detonate after a selected time. As will be appreciated, an example of a time delay detonator includes time delay hardware, an igniter, an electronic time delay or pyrotechnical time delay fuse, and a firing pin cartridge. The time delay may allow for a selected delay time of, for example, 5 to 10 minutes, between the activation of the firing head to the release of a firing pin into a receiving gun. This delay time interval may allow the perforating gun assembly to be repositioned in the well, such as moved axially along the well to a new depth or to perform another operation, as desired. To control the selected time, the rating or number of fuses may be selected, or an electronic controller may be used, for any one or more of the time delay detonators.

Tubing arrangement 14 may include an unmodified tubular sub or may include one or more subs with straight tubing or any of various mechanisms, as desired, considering the operation of the assembly including the operation of the perforating gun and selected downhole operations to be conducted. For example, the tubing arrangement may include any or all of a swivel, a shear release, a fluid outlet sub, or other mechanisms. For example, a fluid outlet sub may be incorporated in the tubing arrangement where it is desired to direct fluid from the assembly into the annulus. A fluid outlet sub including, for example, a valve, an openable port, etc. may allow fluid to be contained in the tubing arrangement until it is desired to open the outlet to the exterior of the assembly. Such an outlet sub may be for example, a sleeve-closed port such as the tubing drain 40, as shown, or otherwise. Tubing drain 40, in the illustrated embodiment, includes a pressure release connection with a shear pin arrangement 42 that can be overcome by fluid pressure to create an opening through the wall of the drain. The shear pin arrangement can, for example, release the connection between a telescoping outer sleeve and an inner tube into which bore 20 extends and ports 44 are formed. It may be desired to open fluid communication to the outer surface, and thereby annulus 27 about the perforating gun assembly, for annular hydraulic actuation of a perforating gun, such as is shown in FIG. 1, for wellbore treatment such as conveying an acid or other fluid through the tubing string, for pressuring testing a packer or plug, and/or for equalizing pressure between the tubing string/perforating gun assembly and the wellbore.

In another embodiment, where it is not desirable to open fluid access to the outer surface of the tool and annulus about the tool until nearer the time or after the perforating gun is detonated, a port can be provided in association with the firing head. For example, a port can be provided that is positioned to be covered by the firing head body or an extension thereof and which is opened by movement of the firing head, after the firing head has been sufficiently hydraulically actuated to initiate detonation of the perforating gun.

As a further example, it may be useful to employ a swivel in the tubing arrangement to allow the assembly to be rotated relative to the tubing string long axis. In the illustrated embodiment, a swivel 46 is incorporated in the tubing arrangement. Swivel 46 allows, for example, the assembly to be rotated to allow a side of the assembly, for example that side carrying bypass line 24, to be out of contact with the wellbore wall.

Although the illustrated components of the tubing arrangement, swivel 46 and tubing drain 40, are shown positioned in a particular orientation and formed in a particular way. Of course, other positional orientations and forms can be employed, if these components are used at all.

As noted, bore 20 of tubing arrangement 14 may include a plug, such as plug 22, that can be a valve, a frangible member, or a permanent member such as a wall. Plug 22, when it is in place, isolates perforating gun 16, from through tubing conveyed hydraulic pressure, for example, when using bypass line 24 and hydraulically manipulating tool 18. In particular, plug 22 blocks fluid passage along bore 20 such that pressure applied to the tubing string inner bore passes through bypass line 24 rather than acting on the perforating gun's firing head. Plug 22 may be positioned anywhere between the intersection of bypass line 24 and bore 20 and firing head 30. Of course, a plug can be omitted where the firing head is connected, as by selection of shear or biased connections, to only be moved by pressures in selected ranges that are different than those pressure ranges selected to actuate tool.

If perforating gun is hydraulically actuated using any source of tubing conveyed hydraulic pressure, such pressure must eventually be communicated from bore 20 to the firing head. Where an embodiment as shown in FIG. 1 is employed, such communication may be through tubing drain 40 and, as such, plug 22 can be a permanent installation, such as a wall across the bore, as may be provided by a blanking sub, which in the illustrated embodiment is a part of upper sub 28. The embodiment of FIG. 2 shows an embodiment where perforating gun 116a is actuated entirely by through tubing pressure acting against firing head 130. In such an embodiment, a plug 122 may be positioned in bore 120 to direct flow to bypass line 124 and to block fluid communication to the perforating gun. In such an embodiment, plug 122 is openable to allow fluid communication to the firing head, when desired. For example, plug 122 may be frangible such as by use of a burst disc or shear pin released sleeve to open communication through bore 120 to firing head 130. Alternately, plug 122 may be omitted, allowing the actuating pressure for tool 118 to reach firing head 130, and instead rely on the pressure rating of the firing head's shear pin connection to select pressure that will detonate the perforating gun.

Bypass line 24, as noted above, conveys a flow of fluid from bore 20 to a tool 18 positioned on the other side of the perforating gun from bore 20, which in wellbore operations would be considered downhole from the perforating gun. Hydraulic actuation can be by various fluids including liquid or gas, such as including but not limited to drilling mud, water, nitrogen, etc. Line 24 is selected to withstand the rigors of downhole use and to convey fluid and hold pressure at the differentials selected for operation. In some embodiments, it may be possible to position and form line 24 to withstand and retain its fluid conveying function even after perforating gun has been detonated. This may be achieved by forming the line of durable materials and positioning line 24 out of alignment with the explosive path of the perforating gun charges.

In one embodiment, bypass line 24 is connected between an upper sub 48 and a lower sub 50. An example of an upper sub 248 is shown in FIG. 3, which is useful, for example, in an embodiment such as FIG. 1 or FIG. 2.

Using upper sub 248 as an example of a form useful for the upper sub and the lower sub for retaining bypass line 224, the sub includes connections such as a threaded connections 252, 253 that permit the sub to be connected into a tubular string. As an upper sub, one end 252 is connected to the next adjacent component of the tubing arrangement, such as tubing swivel 46 in FIG. 1. The other end 253 is connected directly or indirectly to an end of perforating gun, such as to the blanking sub or to upper gun sub 28 and therethrough to perforating gun 16.

Sub 248 also includes a bore 220a that may be connected into communication with a bore of the tubing arrangement, such as bore 20 in FIG. 1. Sub 248 further includes a port 254 from bore 220a onto which bypass line 224 can be fit. Sub 248 may include supports 255 that extend to support and protect line 224 at positions between the line's installed ends. The bypass line can be for example a durable tube, such as of metal or polymer including as one possible example a stainless steel tube. Bypass line 224 is connected at its other end in a similar manner to a substantially similar, but vertically reversed, lower sub. Upper sub 248 and the lower sub are positioned on opposite ends of the perforating gun such that the bypass line spans the perforating gun without opening thereto. Any connections between the line and the sub are selected to be substantially fluid tight, such that any fluid communicated to sub 248 can get past the perforating gun by flowing through line 224 and into a lower sub to pass to a tool to be actuated.

While bypass line is shown as an external line in FIGS. 1 to 3, it is to be understood that bypass line can alternately extend partly or fully through the perforating gun. For example, a conduit extend along the perforating gun inside the perforating gun housing sleeve 38 and, for example, can be formed through the perforating gun and other components between the bypass upper and lower subs such as by drilling or installing a line through the parts. For example, aligned channels, such as holes or indentations, can be formed through and along the bypass upper and lower subs and the various parts between the bypass upper and lower subs. In one embodiment, a conduit such as a stainless steel line can be installed to form the bypass line. To avoid fluid passage outside the line, seals, such as O-rings can be installed between the line and the parts through which it passes. For example, a seal may be placed between the upper sub body and the conduit such that fluid passing through the upper sub bore passes into the conduit rather than around it. A moving part, such as the firing head, can include a hole therethrough to accommodate the line and can be formed to ride axially along the line. The line can extend between or through the charge tube, if outside the tube, the charges therealong can be positioned to allow the line to pass therethrough. In any event, the line and affected parts of the perforating gun can be formed such that fluid can pass through the line from an upper bypass sub to a lower bypass sub such that fluid conveyed through the line can pass from above the perforating gun to a tool on the other side of the perforating gun (i.e. downhole of the perforating gun from the actuating fluid supply). In some embodiments, the upper sub and the bypass conduit line will be selected such that the fluid passing in the bypass line will be maintained in isolation from the gun and the gun's components.

Tool 18 can take various forms, as noted above, including, for example, a packer, a plug, a shear mechanism, a time delay assembly, a perforating gun, etc. In one embodiment, the tool may include a bridge plug. The form and operations of bridge plugs is well known in the art. For example, a bridge plug may carry an annular seal 60 that can be expanded to set in and seal against a wellbore wall 8. A bridge plug may be carried on the assembly to permit the wellbore below a selected area to be perforated to be sealed off. The seal created by the bridge plug may be useful to restrict wellbore fluid to an area above the plug, to allow the wellbore section above the plug to be pressured up, etc. Various hydraulically actuated bridge plugs are known. When hydraulic pressure is communicated to such a bridge plug, the annular seal is caused to be expanded radially outwardly to seal the well about the plug body 61 and set the plug in the well. It may be useful to provide a centralizer with, for example adjacent, the bridge plug to ensure an appropriate setting position for the plug and to protect it from abrasion. In one embodiment, for example, an offset sub 64 can be installed in the assembly to act as a centralizer. An offset sub includes a sub that has axially offset end connections. While the center long axis of perforating gun 16 may be offset to allow room for bypass line 24 to extend therealong, offset sub 64 positioned below the perforating gun, allows the bridge plug body and annular seal 60 to be returned to a more central position in the well.

Tool 18 can further include a shear release mechanism such as one also actuated by hydraulic pressure. A shear release mechanism allows the assembly thereabove, including for example, perforating gun 16 to be separated from the tool components, including for example the bridge plug, below the shear mechanism, when desired. The shear release mechanism can include, for example, a shear pin connection between parts that can be separated by pressuring up the tool beyond the holding force of the shear pins. Since in some embodiments it is necessary to continue to hold pressure within the assembly to hydraulically actuate further components thereof, a valve may be provided in relation to the shear release to continue to provide a closed system in at least bore 20 and possibly also bypass line 24.

It will be appreciated that in the embodiment of FIGS. 1 and 2, the assembly is in open communication for reverse flow to surface. In particular, there is no valve in the assembly to prevent reverse flow from the assembly to the coiled tubing. This presence of a check valve during all operations of the embodiments of FIGS. 1 and 2 may create problems. However, in some applications, it may be desirable to provide a reverse flow check valve for well control. For example, a reverse flow check valve may be useful to control well kicks, prevent through tubing passage of sour gas to surface and generally prevent debris from migrating up the tubing string. As such, in one embodiment a check valve may be provided in an inoperative position in the assembly for example in tubing arrangement 14, which check valve can be moved into an operative condition when the presence of a check valve is acceptable and desired.

One possible embodiment of a useful check valve sub 470 is shown in FIG. 4. Check valve sub 470 can be installed on an end or along the length of tubing arrangement 414. Sub 470 includes a housing 472 including ends 472a, 472a for connection of the check valve inline with other components of the assembly. Within the housing is a check valve assembly including one or more valves, which in this illustrated embodiment, include two valve bodies 474 and 476, each providing operative support for a pivotal flapper type check valves, 478, 479, respectively. When in an operative condition (FIG. 4B), the flapper valves are each capable of opening in response to downward flow of fluid from the tubing string through a central flow passage 420b in line with, and forming a portion of, bore 420 of the tubing arrangement toward the perforating gun and are moved to the closed positions thereof, with flapper valves seated against seats 480, 481 of the bodies, in response to upward or reverse flow of fluid through housing 472.

As shown in FIG. 4A, the check valves may be initially provided in an inoperative position, where an inner sleeve 482 is inserted into bore 420b to hold flapper valves 478, 479 open. In this condition, fluid flow can move in either direction through the inner diameter of inner sleeve 482 and the remainder of bores 420, 420b. Inner sleeve 482 includes a lower end positioned in sealed relation with the housing inner diameter and able to ride therealong. Inner sleeve 482 also includes a ball seat 484. Although inner sleeve is maintained by shear pins 485 initially in a position holding the check valves in the inoperative position, force can be applied by dropping or pumping a ball 486, or other seal such as a dart, to land in seat 484, the pressure which is built up behind the ball and seat acting to drive the inner sleeve out of the region of the flapper valves such that they are free to act. The sleeve can be formed to be retained in the assembly but to be of such a form or size such that the ball and sleeve, when moved down, do not create a blockage to fluid flow in either direction.

To facilitate installation and construction, a tubular insert 487, which is sealed as by use of o-rings 488 against the inner wall of housing 472, can be used to provide a stepped region in the inner diameter in which the lower end of sleeve 482 can initially be sealed and can ride along.

In use, a perforating gun assembly, such as one of the various embodiments with or without the optional features described hereinbefore, can be run into a position in a well. Thereafter, fluid can be communicated the fluid conduit through the assembly including the bypass line to actuate the hydraulically actuated tool below the perforating gun. Before or after the tool is actuated, the perforating gun may be actuated to perforate the well.

In an assembly such as that shown in FIG. 1, wherein the assembly is hung on and run in on coiled tubing and the assembly itself includes a hydraulically actuated perforating gun acted on at least in part by through tubing conveyed fluid pressure, the method may include the use of staged pressure ratings. For example, the hydraulically actuated tool may be actuated by a first selected pressure differential between the annulus and the fluid conduit, including bore 20, bypass line 24, and any hydraulic chambers of tool 18. Once the hydraulically actuated tool is actuated, the pressure may then be increased to open access between the fluid conduit and the perforating gun firing head. For example, the pressure may be increased to a pressure greater than the first selected pressure differential to open tubing drain 40 (FIG. 1) or to open a burst element of plug 122 (FIG. 2), depending on the nature of operation selected for the assembly. Thereafter, the pressure may again be increased to actuate the perforating gun firing head. This may include flowing fluid down through the coiled tubing alone or through both the coiled tubing and the casing/tubing annulus, depending on the mode of operation of the perforating gun.

The wellbore can be treated by circulation of various fluids, such as acid, at some point, for example, after hydraulically actuating tool 18.

The perforating gun assembly may alternately be used to first detonate perforating gun 16 and then actuate tool 18. This can be achieved in various ways, such as, for example, by mechanically or electrically actuating the perforating gun followed by hydraulically actuating the tool or by selecting the perforating gun to be detonated hydraulically by pressures less than those required to actuate tool 18.

If a check valve such as one of FIG. 4 is provided, a ball can be dropped to render the check valve operable to act against flow uphole through the tubing string, when desired.

The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to those embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein, but is to be accorded the full scope consistent with the claims, wherein reference to an element in the singular, such as by use of the article “a” or “an” is not intended to mean “one and only one” unless specifically so stated, but rather “one or more”. All structural and functional equivalents to the elements of the various embodiments described throughout the disclosure that are know or later come to be known to those of ordinary skill in the art are intended to be encompassed by the elements of the claims. Moreover, nothing disclosed herein is intended to be dedicated to the public regardless of whether such disclosure is explicitly recited in the claims. No claim element is to be construed under the provisions of 35 USC 112, sixth paragraph, unless the element is expressly recited using the phrase “means for” or “step for”.