Dual-stage valve straddle packer for selective stimulation of wells

• US 7,789,163 B2
• Filed: 12/21/2007
• Issued: 09/07/2010
• Est. Priority Date: 12/21/2007
• Status: Expired due to Fees

• Current Assignee: Extreme Energy Solutions, Inc.
• Original Assignee: Extreme Energy Solutions, Inc.
• Inventors: Schofield, Dan, Kratochvil, Robert, Kirk, Scott, Smolcic, Darko
• Primary Examiner(s): Bagnell; David J.
• Assistant Examiner(s): MICHENER, BLAKE E
• Application Number:
  US12/003,269
• Publication Number:
  US 20090159299A1
• Time in Patent Office: 991 Days
• Field of Search: 166/177.5, 166/308.1, 166/188, 166/191, 166/202
• US Class Current: 166/387
• CPC Class Codes: E21B 33/124 Units with longitudinally-spaced plugs for isolating the intermediate space
• CPC Class Codes: E21B 33/1265 with mechanical slips
• CPC Class Codes: E21B 33/12955 using drag blocks frictionally engaging the inner wall of the well
• CPC Class Codes: E21B 43/26 by forming crevices or fractures

Abstract

A straddle packer which, when in place during a fracing or well stimulation service, isolates the fracing zone from zones in the wellbore above and below the fracing zone, and which when run into the wellbore provides an open passageway from below the packer to the tubing string, relieving built up fluid pressure below the tool and permitting insertion at relatively high speeds.

Claims

1. A dual-stage valve straddle packer for insertion into a wellbore and delivery of fracing and stimulation service to a particular zone of the wellbore comprising:

a. a body operatively connected to a tubing string, with fluid communication to the inner bore of the tubing;

b. the body having an upper cup-seal for isolation of fluid delivered under pressure through fracing ports in the body below the upper cup-seal by sealing the annulus between the body and a casing of the wellbore;

c. the body having a set of lower cup-seals for isolation, by a top lower cup-seal of the fracing ports from the wellbore below the top lower cup-seal, and by a bottom lower cup-seal of the wellbore below the bottom lower cup-seal from the fracing ports, each of the lower cup-seals being a one-way seal sealing a higher pressure side from a lower pressure side, the lower cup-seals deployed to seal the annulus between the body and the wellbore'"'"'s casing;

d. a passageway from the wellbore below the bottom lower cup-seal through the body and a valve to ports in the body in fluid communication when the valve is open with the annulus between the body and the wellbore'"'"'s casing at a point above the bottom lower cup-seal and below the upper cup-seal;

e. the valve being capable of opening and closing, responsive to a movement of the body in the wellbore, where an upward movement will close the valve and a downward movement will open the valve.

2. The dual-stage valve straddle packer of claim 1 wherein the valve is a pressure balanced valve.

3. A method of inserting a straddle packer for isolation of a fracing service in a tracing zone from zones in a wellbore above and below the fracing zone, comprising the steps:

a. where the straddle packer has three uni-directional seals, sealing flow from high pressure side to low pressure side, the uppermost seal sealing the low pressure wellbore zone above the tool from a high pressure fracing zone below the uppermost seal;

a middle seal sealing the high pressure fracing zone above the middle seal from a low pressure wellbore zone below the middle seal, and a lowermost seal sealing a high pressure wellbore zone below the lowermost seal from a low pressure fracing zone, the seals being seals when the relative pressures are as stated;

b. where the straddle packer has a body, and a valve capable of opening and closing, responsive to a movement of the body in the wellbore, inserting the straddle packer into the wellbore, and applying a downhole movement, wherein the downhole movement causes the valve to open;

c. opening a passageway between the wellbore below the packer'"'"'s body through the body and through a port to the annulus between the body and the wellbore'"'"'s casing between the lowermost seal and the middle seal;

d. which passageway is then in fluid communication through a fracing port to the tubing string.

4. The method of claim 3 where the valve is caused to close by movement of the packer uphole, isolating the wellbore below the packer from the fracing zone between the uppermost and middle seals for fracing.