US20070012460A1

US20070012460A1 - Hydrostatic-set open hole packer with electric, hydraulic and/or optical feed throughs

Info

Publication number: US20070012460A1
Application number: US11/180,150
Authority: US
Inventors: Martin Coronado
Original assignee: Baker Hughes Inc
Current assignee: Baker Hughes Holdings LLC
Priority date: 2005-07-13
Filing date: 2005-07-13
Publication date: 2007-01-18
Also published as: WO2007008481A1

Abstract

Devices and methods are described for disposing electric, hydraulic and/or optical cables or conduits axially through a hydrostatically-set packer mechanism. Radial fluid communication is also provided through the inner mandrel so that the packer mechanism may be set using hydrostatic pressure within the flowbore. Feed-through paths for the cables or conduits isolate the cables/conduits from fluid pressure as well as axial or torsional tensile forces.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention
The invention relates generally to the design of downhole packers and to mechanisms for passing cables and conduits through a packer. In particular aspects, the invention relates to the design of packers that are set using hydrostatic wellbore fluid pressure.
2. Description of the Related Art
When installing a production string within a wellbore, it is often necessary to form a fluid seal within a large diameter opening, such as an open (uncased) hole. To accomplish this, a packer assembly is needed that can provide large radial expansion of the sealing element. Unfortunately, conventional large expansion packer systems generally lack the ability to pass electrical or fiber optic cables or fluid conduits axially through the packer assembly so that other devices may be used below the packer device.
The desirable requirements for a large diameter packer system are typically at odds with those for a conduit pass-through system. U.S. Pat. No. 6,220,362, issued to Roth et al. describes a pass-through conduit arrangement for a packer assembly or other tool. The Roth patent is owned by the assignee of the present invention and is incorporated herein by reference. Roth describes a system wherein one or more axial conduit passages are formed through an interior portion of a packer or other tool. Roth teaches that there be complete pressure isolation between the conduit and both the tubing and the annulus. However, Roth describes the use of a separate carrier 60 that lies radially within the tool mandrel 24 and is used to define the longitudinal passages for the conduits or cables. The potential exists for improper sealing between the carrier and mandrel during fabrication of the tool, leading to undesirable fluid entry into the longitudinal passages. Additionally, this design does not offer any means for radial communication of fluid outwardly from the flowbore of the tool to the radial exterior of the tool. In fact, the requirement that the longitudinal passages remain isolated from fluid pressure from the flowbore, as well as the annulus, dictates against penetration of the carrier and/or mandrel by a radial fluid communication passage. If the carrier and mandrel of this tool were perforated to allow radial fluid communication, the passages defined therebetween would undesirably become exposed to external wellbore fluid pressures.
To the inventor's knowledge, conduit feed through systems have not been successfully integrated into hydrostatically-set packer assemblies. It is believed that this failure is due to the complexity of a hydrostatic setting mechanism and the need for such a device to communicate hydrostatic fluid pressure through the inner mandrel of the packer assembly and into a chamber within the exterior portion of the packer assembly. The use of multiple interior pieces, such as a separate carrier and mandrel, to define a longitudinal cable/conduit pass-through, and the attendant assembly requirements, also adds to the difficulty of incorporating a cable feed-through feature into a hydrostatically-set device.
U.S. Pat. No. 6,842,315 issued to Coronado et al., describes a hydrostatically-set packer device having a composite sealing element with large radial expansion capabilities for use in through tubing and open hole applications. This patent is owned by the assignee of the present invention and is, therefore, incorporated by reference. The device of the '315 patent provides no feed-through arrangement for cables or conduits to be passed longitudinally through the packer device.
The present invention addresses the problems of the prior art.

SUMMARY OF THE INVENTION

The invention provides devices and methods for axially disposing electric, hydraulic and/or optical cables or conduits through the inner mandrel of a hydrostatically-set packer mechanism. In accordance with the devices and methods of the present invention, radial fluid communication is also provided through the inner mandrel so that the packer mechanism may be set using hydrostatic pressure within the flowbore. The axial feed-through path(s) for the cables or conduits are isolated from flowbore and annular fluid pressure. Additionally, the cables/conduits are protected from axial tensile forces and torsional forces that might damage them.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A-1C present a side, cross-sectional view of an exemplary packer assembly with conduit feed through system constructed in accordance with the present invention.
FIG. 2 is an axial cross-section taken along lines 2-2 in FIG. 1C.
FIG. 3 is an axial cross-section taken along lines 3-3 in FIG. 1C.
FIGS. 4A-4C present a side, cross-sectional view of the packer assembly shown in FIGS. 1A-1C, now with the packer element having been set.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIGS. 1A-1C, 2, and 3 illustrate an exemplary hydrostatically-set packer assembly 10 that is constructed in accordance with the present invention. The packer assembly 10 includes a central mandrel 12 having an upper threaded end 14 which allows the packer assembly 10 to be incorporated into a production tubing string. The central mandrel 12 defines a central axial flowbore 16 along its length. A cable feed through path, generally designated as 18, passes through the central mandrel 12. Beginning at the upper end of the packer assembly 10, the central mandrel 12 features a radially enlarged upper portion 20 with outer threads 22. Below the enlarged upper portion 20 is a radially reduced mandrel portion 24. At the lower end of the radially reduced portion 24 is a lower radially enlarged portion 26. The enlarged portion 26 also defines an enlarged bore portion 27 within. The lower portion 26 presents an outwardly projecting shoulder 28 and a threaded connection 30 to a lower end sub 32. The lower end sub 32 includes a set of interfitting longitudinal anti-rotation splines 34 and an axial cable passage 36. The splines 34 engage complimentary splines 35 formed on the outside of the central mandrel 12. Below the cable passage 36 is a lateral cable opening 38.
In a currently preferred embodiment, the feed-though path 18 includes an axially-oriented longitudinal central portion 40 and an upper angled end portion 42 that extends from the upper end of the central portion 40 radially outwardly to an axial upper end passage 44. The axial upper end passage 44 includes an enlarged bore 46 that is shaped and sized to accommodate end nut 48. The lower end of the central portion 40 interconnects to a lower angled end portion 50 that extends radially outwardly to an axially-oriented lower portion 52. The lower end of the lower portion 52 also has an enlarged bore 54 that is shaped and sized to accommodate an end nut 56. It is noted that the feed-through path 18, and all of its individual components 40, 42, 50, 52, are preferably constructed by drilling of suitably sized holes or passages through the central mandrel 12. The component portions 40, 42, 50, 52 should interconnect with one another axially to provide a continuous path. An exemplary cable 58 is shown disposed within the feed-through path 18 and secured therewithin by end nuts 48, 56. It can be seen that a portion 60 of the cable 58 extends upwardly toward the entry of the wellbore (not shown) while another portion 62 of the cable 58 extends downwardly toward a location below the packer assembly 10. Thus, the cable feed-through path 18 allows communication through the packer assembly 10 to a device (not shown) that is located below the packer assembly 10. It is noted that the term “cable,” is used herein to refer to an electrical cable, a hydraulic fluid conduit, a fiber optic cable, or any other type of tubular structure that is used to transmit fluid, power or communications into or out of a wellbore.
The enlarged bore portion 27 of the central mandrel 12 accommodates an actuating sleeve 62 and an internal guide sleeve 64. The guide sleeve 64 provides a radially exterior surface 66 that defines the inner boundary of the lateral cable opening 38. Additionally, the guide sleeve 64 presents an inner surface 68 with an upper radially is enlarged bore portion 70. The actuating sleeve 62 presents an inner surface 72 that extends radially inwardly of the enlarged bore 70, thereby creating an engagement shoulder 74 at the lower end of the sleeve 62. The outer radial surface 76 of the actuating sleeve 62 carries a number of annular fluid seals 78, a dog recess 80 and a locking ring 79. It is noted that the actuating sleeve 62 is axially moveable between a lower position, shown in FIG. 1, wherein the lower end of the sleeve 62 contacts the guide sleeve 64, and an upper position, shown in FIG. 2, wherein the upper end 82 of the actuating sleeve 62 contacts an internal stop shoulder 84 of the central mandrel 12. Frangible shear screws 82 pass through the body of the central mandrel 12 and into the actuating sleeve 62 to initially secure the actuating sleeve 62 in its lower position.
A plurality of radial fluid communication ports 88 also pass through the central mandrel 12 to provide fluid communication between the internal flowbore 16 of the mandrel 12 and its radial exterior. As FIG. 2 illustrates, the shear screws 82 are angularly offset from each of the fluid ports 88 about the circumference of the central mandrel 12. Fluid flow through the fluid ports 88 is initially blocked by the presence of the actuating sleeve 62 and fluid seals 78.
Beginning once again proximate the upper end of the packer assembly 10, a second set of longitudinal anti-rotation splines 90 are defined upon the central mandrel body 12. Splines 90 interfit with complimentary anti-rotation splines 92 on the central mandrel 12. The interfitting of the splines 90, 92 prevents rotation of the central mandrel 12 components with respect to one another.
The ring 98 is retained in place upon the outer surface of the central mandrel 12 by a housing sub 100 that is secured to the central mandrel 12 by threaded connection 22. An annular space 102 is defined between the lower end of the housing sub 100 and the outer surface of the central mandrel 12. Ring 104 is secured to the lower end of the housing sub 100 at threaded connection 106. The ring 104 provides tensioning portions 105, of a type known in the art, for exerting a tensioning force upon the packer element 110.
An upper end setting sleeve 108 also surrounds the central mandrel 12 below the ring 104. The setting sleeve 108 is used to help set the packer element 110 that lies immediately below it on the radial exterior of the central mandrel 12. During setting of the packer assembly 10, the upper end setting sleeve 108 remains stationary with respect to the central mandrel 12. The upper end setting sleeve 108 has a retainer portion 112 that extends over a portion of the packer element 110. A lower end setting sleeve 114 is located at the lower end of the packer element 110 and also presents a retainer portion 116 that extends over a portion of the packer element 110.
The packer element 110 is preferably a composite packer element as described in U.S. Pat. No. 6,843,315, issued to Coronado et al. This patent is owned by the assignee of the present invention and is herein incorporated by reference. This type of packer element is suitable for use in creating a fluid seal in larger bores and even uncased borehole sections. Below the lower end setting sleeve 114 is a setting, or actuating, assembly, generally shown at 118, having an upper sub 120 with fluid fill port 122, a setting assembly housing 124 and a lower sub 126. The setting assembly housing 124 encases an atmospheric chamber 128. The atmospheric chamber 128 is bounded at axial ends by the upper and lower subs 120, 126. When the piston assembly 10 is in the unset position (shown in FIG. 1), the atmospheric chamber 128 is at atmospheric pressure.
An actuating piston, generally shown at 130, is retained within the atmospheric chamber 128. The actuating piston 130 is made up of a lower piston ring 132, central ring 134, and an upper piston ring 136, these components being affixed to one another by threaded connections 138, 140. The lower piston ring 132 presents a fluid pressure receiving area 142. Additionally, the lower piston ring 132 has an annular dog recess 144 inscribed upon its inner surface. Elastomeric O-ring seals 146 are used to provide fluid sealing between the actuating piston 130 and the chamber 128. The upper end of the upper piston ring 136 is secured by threaded connection 148 to a body lock ring assembly 150. The body lock ring assembly 150 includes a locking ring 152 with an inner ratchet surface 154. The ratchet surface 154 is formed to interengage with outwardly-facing ratchet surface 156 on central mandrel 12. Packer element setting member 158 is affixed to the body lock ring assembly 150 and presents an enlarged setting portion 160 that abuts the lower end of the packer element 110.
A locking dog 162 initially secures the actuating piston 130 and the central mandrel 12 together. In the unset position, shown in FIG. 1, the dog 162 resides within a dog passage 164 that is disposed radially through the central mandrel 12. A portion of the dog 162 extends outwardly into dog recess 144 in the actuating piston 130. Movement of the dog 162 radially inwardly is blocked by the presence of actuating sleeve 62. It is noted that the dog 162 and all shear screws 82 are radially offset from the cable feed-through path(s) 18 so that the feed-through path(s) 18 remain unexposed to fluid ingress and wellbore pressures. This arrangement is best shown in FIGS. 2 and 3.
Hydrostatic forces are used to set the packer device 10. FIGS. 4A-4C show the packer device 10 in a set condition. When it is desired to set the packer assembly 10, a shifting tool (not shown), of a type known in the art, is disposed into the flowbore 16 of the central mandrel 12. The shifting tool contacts the engagement shoulder 74 of the actuating sleeve 62 and moves the actuating sleeve 62 axially upwardly. This movement will shear the shear screws 82 and unblock fluid communication ports 88. The locking ring 79 secures into a mating recess in the central mandrel 12 (see FIG. 4C) to secure the actuating sleeve 62 in the upward position. Additionally, upward movement of the actuating sleeve 62 will bring the dog recess 80 into general alignment with the locking dog 162. The dog 162 is moved radially inwardly to reside partially within the recess 80 and is thus moved out of the outer dog recess 144. This unlocks the actuating piston 130 from engagement with the central mandrel 12. As upward movement of the actuating sleeve 62 unblocks the fluid ports 88, hydrostatic fluid pressure present within the flowbore 16 will then be transmitted through the ports 88 and enter the pressure receiving area 142. Wellbore hydrostatic pressure will bear upon the pressure receiving area 142 of the actuation piston 130 and urge the piston 130 axially upwardly. The packer element setting member 158 will compress the packer element 110 axially to cause it to expand radially and become set.
It can be seen that the arrangement of the present invention provides a means for disposing one or more cables axially through a hydrostatically-set packer device while also permitting radial fluid communication through the central mandrel. The feed-through paths 18 of the packer assembly 10 desirably isolate the cables from fluid pressure present in either the flowbore 16 or the annulus surrounding the packer device 10. Because the feed-through paths 18 are angularly offset from the fluid communication ports 88 about the circumference of the central mandrel 12, fluid pressure being communicated radially through the mandrel 12 will not enter the feed-through paths 18.
Cables extending through the feed-through paths 18 are also protected from axial tensional forces that would be exerted upon the packer assembly 10 as it is being used as well as torsional forces that might be experienced as the packer assembly 10 is being made up or run in the well. The cables are retained in place within the feed-through path(s) 18 by end nuts 48, 56, which secure them to the central mandrel 12.
Those of skill in the art will recognize that numerous modifications and changes may be made to the exemplary designs and embodiments described herein and that the invention is limited only by the claims that follow and any equivalents thereof.

Claims

1. A packer assembly for creating a fluid seal within a wellbore comprising:

a tubular central mandrel having an upper end and a lower end, defining a central flowbore and having an outer radial surface;

a packer element surrounding the tubular mandrel, the packer element being moveable between a radially reduced unset position and a radially expanded set position;

a hydrostatic setting assembly for selectively causing the packer element to be set in its expanded position, the hydrostatic setting assembly comprising:

a) a radial fluid communication port for communicating hydraulic fluid pressure within the central flowbore through the tubular mandrel to its outer radial surface;

b) a piston element for receiving fluid pressure from the central flowbore and applying said fluid pressure to urge the packer element toward its set position; and

a cable feed-through path defined within the tubular mandrel to allow a cable to pass from the upper end of the mandrel to the lower end of the mandrel.

2. The packer assembly of claim 1 wherein the cable feed-through path comprises a longitudinal drilled hole in the mandrel.

3. The packer assembly of claim 1 wherein the setting piston is releasably secured to the central mandrel by a locking dog.

4. The packer assembly of claim 1 wherein the fluid communication port is angularly offset from the feed-through path about the circumference of the central mandrel.

5. The packer assembly of claim 1 wherein the setting assembly further comprises an actuating sleeve that lies within the central flowbore and is moveable between a first position, wherein fluid communication through the radial fluid communication port is blocked, and a second position, wherein the actuating sleeve does not block the port.

6. The packer assembly of claim 5 wherein the actuating sleeve presents an engagement shoulder that is shaped and sized to be contacted by a suitable shifting tool for movement of the actuating sleeve from its first to its second position.

7. The packer assembly of claim 5 wherein:

the setting piston is releasably secured to the central mandrel by a locking dog; and

wherein movement of the actuating sleeve from the first to the second position releases the setting piston from the central mandrel.

8. The packer assembly of claim 1 wherein the packer element comprises a composite packer element for use in creating a fluid seal within an uncased borehole.

9. A system for disposing a cable axially through a packer device that is set hydrostatically, the system comprising:

a central tubular mandrel defining a flowbore to contain hydrostatic pressure;

a packer element carried by the central mandrel, the packer element being moveable between an unset position and an axially compressed set position;

a setting mechanism for moving the packer element to its set position in response to hydrostatic pressure within the flowbore; and

a feed-through path defined axially through the mandrel, the feed-through path retaining a cable in isolation from external fluid pressures.

10. The system of claim 9 further comprising:

a radial fluid communication port for transmitting hydrostatic fluid pressure from the flowbore to an actuation chamber located radially outside of the central mandrel; and

wherein the fluid communication port is angularly offset from the feed-through path about the circumference of the central mandrel.

11. The system of claim 9 wherein the feed-through path comprises a longitudinal drilled hole in the central mandrel.

12. The system of claim 10 wherein the setting mechanism further comprises a piston element retained within the actuation chamber for receiving fluid pressure from the central flowbore and applying said fluid pressure to urge the packer element toward its set position.

13. The system of claim 12 wherein the piston element is releasably secured to the central mandrel.

14. The system of claim 13 wherein the piston element is releasably secured to the central mandrel by a locking dog.

15. The system of claim 9 wherein the setting mechanism further comprises an actuating sleeve that lies within the flowbore and is moveable between a first position, wherein fluid communication through the radial fluid communication port is blocked, and a second position, wherein the actuating sleeve does not block the port.

16. The system of claim 15 wherein the actuating sleeve is releasably retained in the first position by a shear pin.

17. A method of disposing a cable axially through a hydrostatically-set packer device, the method comprising the steps of:

forming a cable pass-through path within a central mandrel of the packer device;

disposing a cable along the cable pass-through path; and

securing an end nut upon the cable to secure the cable to the central mandrel.

18. The method of claim 17 wherein the step of forming a pass-through path within the central mandrel comprises drilling a longitudinal hole within the central mandrel that is shaped and sized to accommodate the cable.