System and method for forming a lateral wellbore

Patent metadata

Field	Value
Publication number	US-2016348441-A1
Application number	US-201615235822-A
Country	US
Kind code	A1
Filing date	Aug 12, 2016
Priority date	Apr 9, 2012
Publication date	Dec 1, 2016
Grant date	—

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

1 - 18 . (canceled)

19 . A system for excavating a lateral wellbore from an intermediate portion of a primary wellbore, the system comprising:
a drill bit assembly having a body with one or more cutting elements disposed thereon and a selectively deployable pilot bit, the pilot bit selectively extendable and retractable with respect to a forward face of the drill bit assembly; a means for changing an angle of the drill bit assembly with respect an axis of the primary wellbore; a means for rotating the drill bit assembly within the intermediate portion of the primary wellbore at the same time the angle of the drill bit assembly is being changed; a means for selectively extending the pilot bit; and a means for selectively retracting the pilot bit.

19 . The system of claim 19 , further comprising a bore in the body that is in fluid communication with a source of pressurized fluid, fluid passages in the body that are in fluid communication with the bore, and leads in the body that are in communication with the fluid passages and that have an end that intersects with a cutting surface on the body, so that when fluid is delivered to the bore at a pressure sufficient to deploy the pilot bit, the fluid exerts a force onto the pilot bit to selectively deploy the pilot bit from the body, and the fluid flows through the fluid passages and leads and is discharged from the leads at the cutting surface.

21 . The system of claim 19 , further comprising a payload that indicates a depth of the drill bit assembly and if the drill bit is located on a high side of the primary wellbore.

22 . The system of claim 21 , wherein the drill bit assembly comprises segments having axes that are selectively offset from one another to define a bend in the bit assembly, and a drill bit disposed on an end of the segments, and wherein when the segments are axially offset from one another a side of the drill bit is urged into excavating contact with a side of the wellbore to form a groove in the side of the wellbore.

23 . The system of claim 22 , wherein the pilot hit remains retracted in the drill bit when the groove is formed.

24 . The system of claim 19 , wherein the means for rotating the drill hit assembly comprises a mud motor, wherein the drill bit assembly is attached to an end of a drill string, and wherein the drill string is selectively rotated.

25 . The system of claim 24 , wherein the mud motor operates at a pressure that is less than a pressure in the drill bit assembly that is required to deploy the pilot bit.

26 . The system of claim 24 , wherein the drill bit assembly comprises segments having axes that are selectively offset from one another to define a bend in the bit assembly, and wherein an angle of the bend is adjustable automatically in response to a pressure drop across the mud motor.

27 . The system of claim 24 , wherein the drill bit assembly comprises segments having axes that are selectively offset from one another to define a bend in the bit assembly, and Wherein an angle of the bend is adjustable automatically in response to a weight applied to the mud motor.

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

• E21B7/064

  specially adapted drill bits therefor · CPC title

• E21B4/02

  Fluid rotary type drives · CPC title

• E21B10/322 Primary

  cutter shifted by fluid pressure (E21B10/345 takes precedence) · CPC title

• E21B47/00

  Survey of boreholes or wells (monitoring pressure or flow of drilling fluid E21B21/08) · CPC title