Downhole Tools and Methods for Selectively Accessing a Tubular Annulus of a Wellbore

• US 20120085548A1
• Filed: 10/06/2011
• Published: 04/12/2012
• Est. Priority Date: 10/06/2010
• Status: Active Grant

• Current Assignee: Colorado School of Mines
• Original Assignee: Colorado School of Mines
• Inventors: Fleckenstein, William Winfrid, Flaska, Todd Lance
• Granted Patent: US 8,991,505 B2
• Time in Patent Office: Days
• US Class Current: 166/373
• CPC Class Codes: E21B 2200/05 Flapper valves
• CPC Class Codes: E21B 34/063 Valve or closure with destructible element, e.g. frangible disc E21B34/103 takes precedence
• CPC Class Codes: E21B 34/142 unsupported or free-falling elements, e.g. balls, plugs, darts or pistons
• CPC Class Codes: E21B 43/14 Obtaining from a multiple-zone well
• CPC Class Codes: E21B 43/26 by forming crevices or fractures

Abstract

A downhole tool is provided that selectively opens and closes an axial/lateral bore of a tubular string positioned in a wellbore used to produce hydrocarbons or other fluids. When integrated into a tubular string, the downhole tool allows individual producing zones within a wellbore to be isolated between stimulation stages while simultaneously allowing a selected formation to be accessed. The downhole tools and methods can be used in vertical or directional wells, and additionally in cased or open-hole wellbores.

Claims

1. A downhole tool adapted for use in a tubular string to selectively treat one or more hydrocarbon production zones, comprising:

an upper end and a lower end adapted for interconnection to a tubular string;

a catch mechanism positioned proximate to said lower end and adapted to selectively catch or release a ball traveling through said tubular string;

a sleeve which travels in a longitudinal direction between a first position and a second position, and which is actuated based on an internal pressure in the tubular string, said sleeve preventing a flow of a treatment fluid in a lateral direction into an annulus of the wellbore while in said first position, and permitting the flow of the treatment fluid in the lateral direction through at least one port in said second position; and

a flapper valve in operable engagement with said sleeve, wherein when said sleeve is in said second position, the treatment fluid cannot be pumped downstream of said flapper valve in the tubular string.

2. The downhole tool of claim 1, wherein said catch mechanism comprises a collet assembly which allows said ball to pass if the pressure in said tubular string is above a predetermined level.

3. The downhole tool of claim 1, wherein said flapper valve is biased to facilitate the closing of said flapper valve when said sleeve is in said second position.

4. The downhole tool of claim 1, wherein said ball is comprised of a degradable material which disintegrates over a predetermined period of time.

5. The downhole tool of claim 1, further comprising a latch mechanism which retains said flapper valve in an upright position which allows the substantially unrestricted flow of fluid through said tubular string during the production of fluids from said hydrocarbon production zones.

6. The downhole tool of claim 1, wherein said sleeve is actuated between said first position and said second position by maintaining said pressure for a predetermined period of time.

7. The downhole tool of claim 1, wherein said catch mechanism retracts to a position with an increased internal diameter when said sleeve is in said second position.

8. The downhole tool of claim 1, further comprising a plurality of packers positioned in said string of production tubing to seal the wellbore annulus between said string of production tubing and said wellbore to isolate one or more hydrocarbon production zones.

9. The downhole tool of claim 1, wherein said sleeve travels at a varying rate between said first position and said second position.

10. A method for treating a plurality of hydrocarbon production zones at different locations in one or more geologic formations, comprising:

providing a wellbore with an upper end, a lower end and a plurality of producing zones positioned therebetween;

positioning a string of production tubing in the wellbore, said string of production tubing having an upper end and a lower end;

providing a plurality of selective opening tools in said production string, each of said selectively opening tools having a minimum internal diameter which are substantially the same;

pumping a treatment fluid containing a first ball through the production tubing at a predetermined pressure until said first ball reaches a first selective opening tool positioned proximate to a predetermined portion of the hydrocarbon production zone;

changing the internal pressure in said production tubing to retain said first ball in a catch mechanism in said first selective opening tool;

retaining the pressure in said first selective opening tool for a predetermined time period to move a sleeve from a first position to a second position, wherein in said first position the treatment fluid is prohibited from traveling laterally into an annulus of the wellbore and in a second position a port is opened to allow the treatment fluid to flow into a wellbore annulus;

closing a flapper valve to prevent the flow of treatment fluid downstream of said flapper valve in said production tubing;

pumping the treatment fluid into a portion of at least one geologic formation;

reducing the pressure in said production tubing;

pumping the treatment fluid with a second ball having a diameter substantially the same size as a diameter of said first ball through said production tubing to a second selective opening tool positioned proximate to a second zone of the hydrocarbon production zone;

retaining the pressure in said second selective opening tool for a predetermined time period to move a sleeve from a first position to a second position in said second selective opening tool, wherein in said first position the treatment fluid is prohibited from traveling laterally into an annulus of the wellbore and in a second position a port is opened to allow the treatment fluid to flow into the wellbore annulus;

closing a flapper valve in said second selective opening tool to prevent the flow of treatment fluid downstream of said flapper valve in said production tubing; and

pumping the treatment fluid into a second portion of at least one geologic formation.

11. The method of claim 10, further comprising flowing said first and said second balls to the upper end of the production string.

12. The method of claim 10, wherein said treatment fluid comprises at least one of an acid, a proppant material, and a gel.

13. The method of claim 10, further comprising a plurality of packers positioned in said string of production tubing which are located in the wellbore to seal the annulus between said string of production tubing and said wellbore to isolate one or more hydrocarbon production zones.

14. The method of claim 10, further comprising restricting the rate of sleeve movement from said first position to said second position for a predetermined displacement.

15. The method of claim 14, wherein said restricting the rate of sleeve movement comprises exchanging fluid through a weep hole disposed between an upper and lower reservoir.

16. A subterranean tool adapted for interconnection with a tubular string positioned in a wellbore to allow selective access to an annulus of the wellbore, comprising:

an axial bore in fluid communication with an internal bore of the tubular string;

a lateral bore in fluid communication with a tubular annulus defined by an inner wall of the wellbore and the outer surface of the tubular string;

a sliding sleeve which covers said lateral bore in a first position, and exposes said lateral bore in a second position to allow fluid communication between the inside of said tubular string and said tubular annulus;

a catch mechanism adapted for selectively allowing the passage of a ball in a first position of use, and for retaining and sealing said ball in a second position of use, wherein in said second position of use said ball and said catch mechanism prevent the flow of fluid in said tubular string downstream of said catch mechanism;

a counting means in operable communication with said catch mechanism, said counting means identifying how many of said balls have passed through said catch mechanism; and

sleeve activation means interconnected to said sleeve, wherein when a predetermined number of balls are identified by said counting means, said sleeve selectively moves from said first position of use to said second position of use to allow fluid to flow through said lateral ports.

17. The apparatus of claim 16, wherein said catch mechanism allows the passage of said ball in a direction towards an upper end of said tubular string while in said second position of use.

18. The apparatus of claim 16, further comprising signal means in operable communication with said counting means, said signal means adapted to signal said catch mechanism to be in either said first position of use, or said second position of use.

19. The apparatus for claim 16, wherein said sleeve activation means is triggered by a predetermined pressure in said tubular string proximate to said subterranean tool.

20. The apparatus for claim 16, wherein said catch mechanism comprises a collet assembly which selectively retains or releases a ball traveling in a downstream direction, yet allows the passage of balls traveling in an opposite direction.