Bottom hole assembly

• US 6,832,654 B2
• Filed: 06/28/2002
• Issued: 12/21/2004
• Est. Priority Date: 06/29/2001
• Status: Expired due to Term

• Current Assignee: Baker Hughes Holdings LLC (Baker Hughes Company)
• Original Assignee: BJ Services Company
• Inventors: Ravensbergen, John Edward, Wilde, Graham, Lambert, Mitch, Naumann, Andre, Vacik, Lubos
• Primary Examiner(s): Bagnell, David
• Assistant Examiner(s): STEPHENSON, DANIEL P
• Application Number:
  US10/186,260
• Publication Number:
  US 20030019628A1
• Time in Patent Office: 907 Days
• Field of Search: 166/98, 166/177.5, 166/181, 166/187, 166/191, 166/308, 166/372, 166/377, 166/387
• US Class Current: 166/308.1
• CPC Class Codes: E21B 17/06 Releasing-joints, e.g. safety joints
• CPC Class Codes: E21B 17/20 Flexible or articulated drilling pipes , e.g. flexible or articulated rods, pipes or cables
• CPC Class Codes: E21B 23/02 for locking the tools or the like in landing nipples or in recesses between adjacent sections of tubing E21B23/03 - E21B23/06 take precedence
• CPC Class Codes: E21B 23/06 for setting packers
• CPC Class Codes: E21B 33/1243 with inflatable sleeves
• CPC Class Codes: E21B 34/063 Valve or closure with destructible element, e.g. frangible disc E21B34/103 takes precedence
• CPC Class Codes: E21B 34/085 with time-delay systems, e.g. hydraulic impedance mechanisms
• CPC Class Codes: E21B 34/101 with means for equalizing fluid pressure above and below the valve
• CPC Class Codes: E21B 43/26 by forming crevices or fractures

Abstract

A bottom hole assembly for use with fracturing or fracing a wellbore using coiled tubing is described having a first packing element and a second packing on a mandrel. The bottom hole assembly may be run into the wellbore such that the packing elements straddle the zone to be fraced. Also described is a timing mechanism to prevent the closing of dump ports before the bottom hole assembly may be flushed of the sand. A release tool is described that allows an operator to apply force to the coiled tubing to dislodge a bottom hole assembly without completely releasing the bottom hole assembly. Also disclosed is a collar locator capable of being utilized in a fracing process. Methods of using the above described components are also disclosed.

Claims

1. A bottom hole assembly for use with coiled tubing for fracturing a zone in a wellbore having a casing, comprising:

a hollow mandrel functionally associated with the coiled tubing, the mandrel surrounded by an outer housing, the outer housing and the casing forming an annulus therebetween;

an upper packing element;

a lower packing element, the upper and lower packing elements disposed around the outer housing such that the packing elements are capable of straddling the zone to be fraced and are capable of setting the bottom hole assembly in the casing when the elements are set;

an upper dump port in the outer housing, the upper dump port placing the annulus and a flow path within the hollow mandrel in fluid communication when an upward force is applied to the mandrel via the coiled tubing to deflate the upper and lower packing elements;

a timing mechanism to ensure the fluid communication continues for a predetermined time to prevent the dump port from closing before the bottom hole assembly is flushed; and

a spring biasing the mendrel such that the dump port prevents the annulus and flow path from being in fluid communication.

2. The bottom hole assembly of claim 1 further comprising a lower dump port in the outer housing, the lower dump port placing the wellbore and the flow path in fluid communication to deflate the lower packing elements, the timing mechanism preventing the lower dump port from closing before the bottom hole assembly is flushed.

3. The bottom hole assembly of claim 1 in which the timing mechanism further comprises:

an upper compartment formed above a shelf on the mandrel, the spring within the upper compartment; and

a lower compartment formed below the shelf on the mandrel, the upper and lower compartments enclosing hydraulic fluid, the mandrel defining a hole to place the upper and lower compartments in fluid communication to allow hydraulic fluid to pass between the compartments as the mandrel moves axially with respect to the outer housing, the spring and the hydraulic fluid acting to ensure the fluid communication between the annulus and the flow path continues for the predetermined amount of time.

4. The bottom hole assembly of claim 1 further comprising at least one orifice in the outer housing, the at least one orifice adapted to provide fluid communication through the mandrel and the outer housing so that a fracing slurry may proceed down the coiled tubing through the flow path in the hollow mandrel, and into the zone to be fraced.

5. The bottom hole assembly of claim 4, in which the at least one orifice further comprises two orifi.

6. The bottom hole assembly of claim 5 in which the two orifi form an angle for reducing erosion of the casing.

7. The bottom hole assembly of claim 6 in which the angle is 90 degrees.

8. The bottom hole assembly of claim 1 in which the hollow mandrel is comprised of carbourized steel.

9. The bottom hole assembly of claim 1 in which an outer diameter of the outer housing is substantially straight and substantially parallel with the casing to prevent sand from building up on the outer diameter of the housing.

10. The bottom hole assembly of claim 9 in which the flow path within the mandrel is substantially straight and substantially parallel with the casing to prevent sand from building up within the mandrel.

11. The bottom hole assembly of claim 10 in which the casing has an inner diameter of 4.5 inches and the outer diameter of the outer housing is 3.5 inches.

12. The bottom hole assembly of claim 9 in which an outer diameter of each packing element when deflated is equal to the outer diameter of the outer housing.

13. The bottom hole assembly according to claim 1 for connecting the coiled tubing to the bottom hole assembly, further comprising:

a collar locator adapted to detect collars in the casing to position the bottom hole assembly such that the packing elements straddle the zone to be fraced.

14. The bottom hole assembly according to claim 13 in which the collar locator further comprises:

a collar locator mandrel;

a key mounted within a key retainer and about the mandrel; and

a spring, the spring being located between the mandrel and the keys to urge the key into contact with the casing.

15. The bottom hole assembly according to claim 14 further comprising a filter in a port to allow the key to move radially when encountering a collar in the casing.

16. The bottom hole assembly of claim 14 further comprising a seal adapted to allow the collar locator to be utilized during the fracing procedure.

17. The bottom hole assembly of claim 14 in which the key has a leading edge at a first angle and a trailing edge at a second angle, the first angle being such that a resulting axial force may be detected at surface by a coiled tubing operator when inserting the bottom hole assembly into the hole, the second angle being such that a resulting axial force may be detected at surface by the coiled tubing operator when removing the bottom hole assembly into the hole.

18. A bottom hole assembly for use with coiled tubing for fracturing a zone in a wellbore having a casing, comprising:

a hollow mandrel functionally associated with the coiled tubing, the mandrel surrounded by an outer housing, the outer housing and the casing forming an annulus therebetween;

an upper packing element;

a lower packing element, the upper and lower packing elements disposed around the outer housing such that the packing elements are capable of straddling the zone to be fraced and are capable of setting the bottom hole assembly in the casing when the elements are set;

an upper dump port in the outer housing, the upper dump port placing the annulus and a flow path within the hollow mandrel in fluid communication when an upward force is applied to the mandrel via the coiled tubing to deflate the upper and lower packing elements; and

a timing mechanism to ensure the fluid communication continues for a predetermined time to prevent the dump port from closing before the bottom hole assembly is flushed;

an upper pressure boost piston in fluid communication with the flow path, the annulus, and the upper inflatable packing element; and

an lower pressure boost piston in fluid communication with the flow path, the annulus, and the lower inflatable packing element, the upper and lower boost pistons operating to increase the pressure inside the upper and lower packing elements.

19. The bottom hole assembly according to claim 18 in which each pressure boost piston further comprises:

a base, and

a surface, the basing having a larger cross sectional surface area than the surface, a pressure differential between a tubing pressure and an annulus pressure creating an upward force on the cross sectional surface area of the base to create the boost.

20. The bottom hole assembly according to claim 19 in which each pressure boost piston further comprises a filter.

21. A bottom hole assembly for use with coiled tubing for fracturing a zone in a wellbore having a casing, comprising:

a hollow mandrel functionally associated with the coiled tubing, the mandrel surrounded by an outer housing, the outer housing and the casing forming an annulus therebetween;

an upper packing element;

a lower packing element, the upper and lower packing elements disposed around the outer housing such that the packing elements are capable of straddling the zone to be fraced and are capable of setting the bottom hole assembly in the casing when the elements are set;

an upper dump port in the outer housing, the upper dump port placing the annulus and a flow oath within the hollow mandrel in fluid communication when an upward force is applied to the mandrel via the coiled tubing to deflate the upper and lower packing elements;

a timing mechanism to ensure the fluid communication continues for a predetermined time to prevent the dump port from closing before the bottom hole assembly is flushed;

an upper packer equalization port; and

a lower packer equalization port,

the upper and lower packer equalization ports functionally associated with an annular space between the mandrel and the outer housing to provide a fluid communication bypass from above the upper packing element to below the lower packing element.

22. The bottom hole assembly of claim 21 in which each packer equalization port further comprises a filter.

23. A bottom hole assembly for use with coiled tubing for fracturing a zone in a wellbore having a casing, comprising:

a hollow mandrel functionally associated with the coiled tubing, the mandrel surrounded by an outer housing, the outer housing and the casing forming an annulus therebetween;

an upper packing element;

a lower packing element, the upper and lower packing elements disposed around the outer housing such that the packing elements are capable of straddling the zone to be fraced and are capable of setting the bottom hole assembly in the casing when the elements are set;

an upper dump port in the outer housing, the upper dump port placing the annulus and a flow path within the hollow mandrel in fluid communication when an upward force is applied to the mandrel via the coiled tubing to deflate the upper and lower packing elements;

a timing mechanism to ensure the fluid communication continues for a predetermined time to prevent the dump port from closing before the bottom hole assembly is flushed;

at least one orifice in the outer housing, the at least one orifice adapted to provide fluid communication through the mandrel and the outer housing so that a fracing slurry may proceed down the coiled tubing through the flow path in the hollow mandrel, and into the zone to be fraced; and

at lease one flow guide, the flow guide changing the direction of the slurry from down the flow path in the hollow mandrel into the zone to be fraced.

24. A bottom hole assembly for use with coiled tubing for fracturing a zone in a wellbore having a casing, comprising:

a hollow mandrel functionally associated with the coiled tubing, the mandrel surrounded by an outer housing, the outer housing and the casing forming an annulus therebetween;

an upper packing element;

a lower packing element, the upper and lower packing elements disposed around the outer housing such that the packing elements are capable of straddling the zone to be fraced and are capable of setting the bottom hole assembly in the casing when the elements are set;

an upper dump port in the outer housing, the upper dump port placing the annulus and a flow path within the hollow mandrel in fluid communication when an upward force is applied to the mandrel via the coiled tubing to deflate the upper and lower packing elements;

a timing mechanism to ensure the fluid communication continues for a predetermined time to prevent the dump port from closing before the bottom hole assembly is flushed; and

a delay mechanism to prevent the packing elements from becoming instantaneously unset when the upward force is applied to the mandrel.

25. The bottom hole assembly of claim 24 in which the delay mechanism further comprises a flow restrictor.

26. A method of fracing a zone in a wellbore having a casing using coiled tubing, comprising:

providing a bottom hole assembly having

a hollow mandrel functionally associated with the coiled tubing, the mandrel surrounded by an outer housing, the outer housing and the casing forming an annulus therebetween,

an upper packing element,

a lower packing element, the upper and lower packing elements disposed around the outer housing such that the packing elements are capable of straddling the zone to be fraced and are capable of setting the bottom hole assembly in the casing when the elements are set,

an upper dump port in the outer housing, the upper dump port placing the annulus and a flow path within the hollow mandrel in fluid communication when an upward force is applied to the mandrel via the coiled tubing to unset the upper and lower packing elements, and

a timing mechanism to ensure the fluid communication continues for a predetermined time to prevent the upper dump port from closing before the bottom hole assembly is flushed;

running the bottom hole assembly into the casing such that the packing elements straddle the zone to be fraced;

setting the upper and lower packing elements by increasing the flow through the flow path in the mandrel;

fracing the zone;

applying an upward force on the coiled tubing to unset the packing elements;

flushing the bottom hole assembly before resetting the packing elements;

providing a release tool having a release tool to connect the hollow mandrel with the coiled tubing, the release tool having a reset mechanism adapted to allow a user to attempt to dislodge the bottom hole assembly when the bottom hole assembly is lodged in the casing, without releasing the bottom hole assembly from the coiled wire tubing;

applying a predetermined force to the release tool via the coiled tubing to attempt to release the bottom hole assembly when the bottom hole assembly is lodged in the casing; and

resetting the release tool to its original position once the upward force is no longer applied to the coiled tubing.

27. The method of claim 26 further comprising:

providing a collar locator; and

using the collar locator to locate the zone to be fraced so that the packing elements may straddle the zone to be fraced.