System and method for forming a lateral wellbore

Patent metadata

Field	Value
Publication number	US-9441420-B2
Application number	US-201313832056-A
Country	US
Kind code	B2
Filing date	Mar 15, 2013
Priority date	Apr 9, 2012
Publication date	Sep 13, 2016
Grant date	Sep 13, 2016

Abstract

A lateral wellbore is formed from a high side of a horizontal portion of a primary wellbore with a drill bit assembly that has a selectively extendable pilot bit. The drill bit assembly is mounted on a lower end of a drill string. A bit guide is disposed adjacent the drill bit assembly for urging the drill bit assembly in a lateral direction against the high side of the primary wellbore. Rotating the drill bit assembly while urging the drill bit assembly upward creates a groove in a subterranean formation adjacent the primary wellbore. This forms a ledge at a far end of the groove. The drill string is then drawn back from the groove, and the pilot bit is deployed. Urging the drill bit assembly forward engages the pilot bit with the ledge, providing leverage for retaining the drill bit assembly in an orientation for excavating the lateral wellbore.

First claim

What is claimed is:

1. A method of branching a lateral wellbore from a primary wellbore comprising:
a. providing a drill bit assembly having a body with one or more cutting elements disposed thereon and a selectively deployable pilot bit;
b. inserting the drill bit assembly into the primary wellbore;
c. excavating a groove in a formation on a lateral side of the primary wellbore;
d. pulling back the drill bit assembly up the wellbore and away from the groove;
e. deploying the pilot bit;
f. repeating the steps of excavating and backing off until a desired offset angle is achieved from forming the lateral wellbore;
g. engaging the groove with the pilot bit; and
h. rotating the drill bit assembly, so that the pilot bit guides the drill bit assembly into excavating contact with the groove and in an orientation for forming the lateral wellbore.

2. The method of claim 1 , wherein a location of the groove ranges the circumference of the primary wellbore.

3. The method of claim 1 , wherein the body comprises segments and wherein step (c) comprises selectively orienting a one of the segments while in the primary wellbore to form a bend in the body and put the drill bit into excavating contact with the lateral side of the primary wellbore.

4. The method of claim 1 , wherein the pilot bit comprises cutters on the pilot bit, and having an increased radius that defines a shoulder, and wherein a radius of the passage is reduced to interfere with the shoulder and to retain the pilot bit within the body.

5. The method of claim 1 , further comprising:
maneuvering the drill bit assembly to a predetermined angle of the lateral wellbore with respect to the primary wellbore; and
advancing the drill bit assembly in the direction of the predetermined angle.

6. The method of claim 1 , further comprising:
coupling the drill bit assembly to a lower end of a drill string; and
rotating the drill string to orient the drill bit assembly such that the one or more cutting elements engage the formation on a high side of the primary wellbore to excavate the groove.

7. The method of claim 6 , further comprising orienting the drill bit assembly at an angle with respect to a longitudinal axis of the drill string so the cutting elements contact a wall of the primary wellbore at a selected azimuth that corresponds with an azimuth of where the lateral wellbore intersects the primary wellbore.

8. The method of claim 7 , further comprising deepening the groove by increasing the angle between the drill bit assembly and the longitudinal axis of the drill string.

9. The method of claim 1 , wherein the lateral wellbore comprises a first lateral wellbore, the method further comprising, retracting the drill bit assembly from the lateral wellbore, moving the drill bit assembly to another designated location along the primary wellbore, and repeating steps (c)-(f) to form a second lateral wellbore.

10. The method of claim 1 , further comprising extending the pilot bit by providing a pressurized fluid to a bore in the body of the drill bit assembly so that the pressurized fluid is in contact with an end of the pilot bit.

11. The method of claim 1 , further comprising retracting the pilot bit with respect to the body of the drill bit assembly and maneuvering the drill bit assembly to a predetermined angle of the lateral wellbore with respect to the primary wellbore with the pilot bit retracted with respect to the body of the drill bit assembly.

12. A method of excavating a lateral wellbore from a high side of an intermediate portion a primary wellbore extending through a subterranean formation, the method comprising:
providing a side-tracking bottom hole assembly (BHA) that comprises:
a drill bit assembly having a body with one or more cutting elements disposed thereon, a bore in the body, and a selectively extendable pilot bit in communication with the bore, the drill bit assembly selectively angled along an axis oblique to an axis of the primary wellbore; and

disposing the drill bit assembly at a designated sidetrack location;
adjusting the side-tracking BHA to a bend angle such that the one or more cutting elements are urged against the subterranean formation on a high side of the intermediate portion of the primary wellbore;
rotating the drill bit assembly to excavate a groove in the subterranean formation;
pulling back the drill bit up the wellbore and away from the groove;
increasing the bend angle such that the pilot bit is oriented toward a ledge defined in the groove;
repeating the steps of excavating and pulling back until a desired offset angle is achieved from forming the lateral wellbore;
extending the pilot bit from within the body by delivering pressurized fluid to the bore that in turn directly contacts the pilot bit and exerts a force onto the pilot bit to slide the pilot bit axially with respect to the body;
engaging the pilot bit with the ledge to anchor the drill bit assembly; and
advancing the drill bit assembly through the ledge and into the subterranean formation adjacent the primary wellbore to excavate the lateral wellbore.

13. The method of claim 12 , further comprising providing a mud motor having adjustable-angle bent housing for adjusting the bend angle of the side-tracking BHA, and bending the housing when the BHA is in the primary wellbore.

14. The method of claim 13 , further comprising:
coupling the side-tracking BHA to a drill string, and
rotating the drill string to orient the drill bit assembly toward the high side of the intermediate portion of the primary wellbore.

15. The method of claim 14 , wherein the step of rotating the drill bit assembly to excavate the groove in the subterranean formation comprises providing a pressurized fluid to the side-tracking BHA to drive the mud motor.

16. The method of claim 15 , wherein the step of extending the pilot bit from within the body comprises providing the pressurized fluid to a bore in the body of the drill bit assembly, wherein the bore is in fluid communication with a passage in which the pilot bit is disposed.

17. The method of claim 12 , wherein the pilot bit is maintained in a retracted position within the body during the step of rotating the drill bit assembly to excavate the groove in the subterranean formation.

18. The method of claim 17 wherein the pressurized fluid is provided to the side-tracking BHA at a pressure sufficient to drive the mud motor, and wherein the pilot bit is maintained in the retracted position within the body by providing the pressurized fluid to a bore in the body of the drill bit assembly at a pressure insufficient to extend the pilot bit from the body, and wherein when the pressurized fluid is further pressurized to a pressure sufficient to deploy the pilot bit, and wherein the further pressurized fluid is put into direct contact with the pilot bit, the pilot bit is extended from the body.

Assignees

• Saudi Arabian Oil Co

Inventors

• Zhou Shaohua

Classifications

• E21B10/26 Primary

  Drill bits with leading portion, i.e. drill bits with a pilot cutter; Drill bits for enlarging the borehole, e.g. reamers (percussion drill bits with leading portion E21B10/40) · CPC title

• E21B7/067

  with means for locking sections of a pipe or of a guide for a shaft in angular relation, e.g. adjustable bent sub · CPC title

• E21B7/046 Primary

  horizontal drilling (drilling with mechanical conveying means E21B7/003) · CPC title

• E21B4/02

  Fluid rotary type drives · CPC title

• E21B7/064

  specially adapted drill bits therefor · CPC title