Dual Bore Swell Packer

Abstract

Two or more bores are machined from a block of material with opposing end connections. The outer surface is rounded and a reactive element is mounted to the mandrel exterior with gauge rings at opposed ends to contain the element when it moves to the set position. Well fluids present or added to the well will trigger the swelling material to extend radially to contact a surrounding tubular for a seal. The small profile of this dual bore barrier allows insertion into smaller casing sizes while maximizing the bore dimension for a reduction in flow resistance. The bores can be evenly spaced about a central axis and can be the same size or different sizes within a range of 20%. The bores can be eccentric to a center axis while being at the same or different radial dimensions from a central axis.

Description

FIELD OF THE INVENTION

The field of the invention is borehole isolation devices and more particularly plugs or packers that have a dual bore and a reactive sealing element triggered by fluid.

BACKGROUND OF THE INVENTION

Dual bore packers or tools are illustrated in U.S. Pat. Nos. 7,565,931; 4,749,036 and 5,685,370. In the past the sealing element system for dual bore packers has involved an actuation system that is mechanically or hydraulically set. The mechanical force or hydraulic pressure axially compress a sealing element to get the element to seal and in some designs the same movement also extends an anchoring feature that rides out radially on one or more tapered sleeves or cones to engage the surrounding tubular.

The description dual bore has been used in contexts where there is but a single flow bore and an auxiliary conduit for hydraulic signal line or other pass through signal or power lines or cables that need to pass through the packer mandrel. In the case of the present invention dual bore is a reference to two flowing streams from different locations that pass through the mandrel whether the service is in treatment, injection or production. One example of a packer with a reactive sealing element is seen in FIGS. 7 and 8 of US 2015/0354315. The section view of FIG. 8 shows a single flow bore 36 and an auxiliary conduit or tube 38, 54 for control lines passing a liquid or gas to other tools. The mandrel with the bypass passage for control lines is described in paragraphs 30 and 31 as being formed of a steel bar.

The present invention is configured to have side by side flow passages for dual flow duty in a production, injection or treatment application. The swelling sealing element covers the mandrel and has gauge rings at opposed element ends to contain the swelling element. Threads are provided at opposed ends of the multiple bores for connection of discrete strings that lead to different locations in the borehole. Preferably the bores are the same size or one bore may be within 20% of the diameter of the adjacent bore if the bore dimensions are different. The packer can be supported off a production packer that has an anchoring feature to compensate for the limited ability for a swelling packer without an anchoring feature to resist directional net forces. The construction of the packer makes it possible to deploy it in smaller casing sizes because of its trim profile for running in without the need for mechanical components that are typically part of packers that are set with pressure or mechanical force. These and other aspects of the present invention will be more readily apparent to those skilled in the art from a review of a description of the preferred embodiment and the associated drawing while recognizing that the full scope of the invention is embodied in the appended claims.

SUMMARY OF THE INVENTION

Two or more bores are machined from a block of material with opposing end connections. The outer surface is rounded and a reactive element is mounted to the mandrel exterior with gauge rings at opposed ends to contain the element when it moves to the set position. Well fluids present or added to the well will trigger the swelling material to extend radially to contact a surrounding tubular for a seal. The small profile of this dual bore barrier allows insertion into smaller casing sizes while maximizing the bore dimension for a reduction in flow resistance. The bores can be evenly spaced about a central axis and can be the same size or different sizes within a range of 20%. The bores can be eccentric to a center axis while being at the same or different radial dimensions from a central axis.

BRIEF DESCIPTION OF THE DRAWINGS

The FIGURE shows an elevation view of a dual bore packer with threaded end connections.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

The packer P has dual bores 10 and 12 that are part of a cylindrically shaped mandrel 16. Bores 10 and/or 12 can be polished to accept a seal assembly that can serve as a closure if needed. An annularly shaped reactive sealing element 18 is flanged by opposed gauge rings 20 and 22 to contain the sealing element 18 in the axial direction as its outer diameter increases from exposure to well fluids or fluids added to the wellbore. The element 18 can be reactive with hydrocarbons or water or other fluids. The element 18 can be triggered to set from merely being run in with a time exposure to well fluid or the triggering fluid could be selectively released from within the element 18. The element 18 can be a single section or multiple abutting annular segments between rings 20 and 22. The element 18 can be resilient rubber, a shape memory foam that responds to thermal inputs to change shape or other reactive materials that will make a seal over time.

Bore 10 can have opposed end connections 24 and 26 and bore 12 can have end connections 28 and 30. These can be threaded or other type of connections to attach tubular strings or tools that are not shown. In the FIGURE the bores 10 and 12 are shown as symmetrical about a central axis 32 and having their centers in the same plane as axis 32. The bores are shown to be the same size but their size and placement with respect to axis 32 can vary. The bore diameter difference can be as much as 20%. The center of the bores can be misaligned with the central axis 32 or aligned. The number of bores can be two or more with male or female threaded end connections or other types of connections to discrete tubular strings. The mandrel material L-80 or other materials that can be machined and compatible with the intended service. The service for each bore at a given time can be identical or discrete. Treatment can be going on through one bore while another bore connected to a different zone can be in production. The mandrel length can be varied to allow a longer element 18 to be used depending on the application. The packer can be retrieved with the strings connected to it when there is another releasable packer used for support. In the case where the other supporting packer or anchor is not releasable the string or strings in between the two barriers can be cut to release the reactive element packer. Optionally, in situations with low bottom hole pressure the reactive element packer could be used without an external support such as a production packer. The element 18 can be a seamless annular shape built on the mandrel 34 or slipped over and adhered to the mandrel 34. In another variation the element 18 can have a longitudinal or spiral seam that is sealed closed with adhesive or fasteners. Each bore can also have a sliding sleeve schematically illustrated as 36 to allow the strings connected to bores 10 and 12 to drain when removing the packer to prevent pulling wet strings or swabbing the borehole. Dual bore completions an also occur in casing as small as 7 inches. The element 18 can be replaced after use to allow reuse of mandrel 34. The packer has no leak paths or o-rings and is very economical to manufacture.

The teachings of the present disclosure may be used in a variety of well operations. These operations may involve using one or more treatment agents to treat a formation, the fluids resident in a formation, a wellbore, and/or equipment in the wellbore, such as production tubing. The treatment agents may be in the form of liquids, gases, solids, semi-solids, and mixtures thereof. Illustrative treatment agents include, but are not limited to, fracturing fluids, acids, steam, water, brine, anti-corrosion agents, cement, permeability modifiers, drilling muds, emulsifiers, demulsifiers, tracers, flow improvers etc. Illustrative well operations include, but are not limited to, hydraulic fracturing, stimulation, tracer injection, cleaning, acidizing, steam injection, water flooding, cementing, etc.

The above description is illustrative of the preferred embodiment and many modifications may be made by those skilled in the art without departing from the invention whose scope is to be determined from the literal and equivalent scope of the claims below:

Claims

1. A borehole barrier assembly, comprising:

a one piece multiple bore mandrel surrounded by a sealing element movable from a run in configuration to a set configuration against a surrounding borehole wall in response to exposure to well conditions, said bores comprising end connections, said strings having diameters within 20% of each other.

2. The assembly of claim 1, further comprising:

discrete tubular strings connected to said end connection of said bores and extending to discrete zones in the borehole for treatment, production or injection service.

3. The assembly of claim 1, wherein:

said bores are aligned with a central axis of said mandrel.

4. The assembly of claim 1, wherein:

said bores are offset from a central axis of said mandrel.

5. The assembly of claim 1, wherein:

said sealing element comprises an annular shape made of at least one piece.

6. The assembly of claim 1, wherein:

said sealing element has a seam.

7. The assembly of claim 1, wherein:

said sealing element responds to fluids present or added to the borehole.

8. The assembly of claim 1, wherein:

said sealing element responds to thermal input from the borehole or from within said sealing element.

9. The assembly of claim 1, wherein:

said end connections are threaded.

10. The assembly of claim 1, wherein:

a valve in each said bore to allow through bore flow when removing said mandrel.

11. The assembly of claim 1, wherein:

said sealing element swells or changes shape to contact the surrounding borehole wall.

12. A borehole treatment, production or injection method, comprising:

connecting the assembly of claim 1 to discrete strings terminating in discrete zones in a borehole;

performing at least one of treatment, production or injection in each of said strings at the same or at different times.

13. The method of claim 12, comprising:

aligning said bores with a central axis of said mandrel.

14. The method of claim 12, wherein:

offsetting said bores from a central axis of said mandrel.

15. The method of claim 12, wherein:

providing said sealing element in an annular shape made of at least one piece.

16. The method of claim 12, wherein:

providing a seam in said sealing element.

17. The method of claim 12, wherein:

making said sealing element responsive to fluids present or added to the borehole.

18. The method of claim 12, wherein:

making said sealing element responsive to thermal input from the borehole or from within said sealing element.

19. The method of claim 12, wherein:

providing threaded end connections on said bores.

20. The method of claim 12, wherein:

providing a valve in each said bore to allow through bore flow when removing said mandrel.

21. The method of claim 12, wherein:

making said sealing element swell or change shape to contact the surrounding borehole wall.

22. The method of claim 12, wherein:

removing the mandrel with cutting at least one of said strings or with an applied pulling force.

23. The method of claim 12, wherein:

supporting said mandrel with a production packer in the borehole.

24. The method of claim 12, wherein:

providing a polish finish in at least one of said bores for selective closure thereof with a plug assembly engaging said polish finish.