Systems and methods for reducing backward whirling while drilling

• US 7,963,347 B2
• Filed: 10/16/2007
• Issued: 06/21/2011
• Est. Priority Date: 10/16/2007
• Status: Active Grant

• Current Assignee: Schlumberger Technology Corporation (Schlumberger NV)
• Original Assignee: Schlumberger Technology Corporation (Schlumberger NV)
• Inventors: Pabon, Jahir Alfonso
• Primary Examiner(s): Beach; Thomas A
• Assistant Examiner(s): Sayre; James G
• Application Number:
  US11/872,943
• Publication Number:
  US 20090095531A1
• Time in Patent Office: 1,344 Days
• Field of Search: 175/320, 175/92, 175/56, 175/75
• US Class Current: 175/75
• CPC Class Codes: E21B 17/00 Drilling rods or pipes; Flexible drill strings; Kellies; Drill collars; Sucker rods; Cables; Casings; Tubings
• CPC Class Codes: E21B 7/00 Special methods or apparatus for drilling

Abstract

According to the invention, a system for drilling a cavity in a medium is disclosed. The system may include a bottom hole assembly. The bottom hole assembly may include a first longitudinal segment and at least one drill bit. The first longitudinal segment may include a first length of chassis having a first cross section. The first cross section may be configured such that the first longitudinal segment may have a greater stiffness in a first lateral direction than in a lateral direction different than the first lateral direction.

Claims

1. A system for drilling a cavity in an earthen medium, wherein the system comprises:

a bottom hole assembly, wherein the bottom hole assembly comprises;

a first longitudinal segment, wherein;

the first longitudinal segment comprises a first length of chassis having a first cross section; and

the first cross section is configured such that the first longitudinal segment has a greater stiffness in a first lateral direction than in a lateral direction different than the first lateral direction resulting in a bending anisotropy;

at least one drill bit, wherein the at least one drill bit is coupled with the first longitudinal segment; and

a second longitudinal segment, wherein;

the second longitudinal segment comprises a second length of chassis having a second cross section; and

the second cross section is configured such that the second longitudinal segment has a greater stiffness in a second lateral direction than in a lateral direction different than the second lateral direction.

2. The system for drilling a cavity in a medium of claim 1 wherein the first cross section is substantially the same as the second cross section.

3. The system for drilling a cavity in a medium of claim 1 wherein at least one of the first longitudinal segment and the second longitudinal segment is selected from a group consisting of:

a connector segment;

a check valve assembly segment;

a pressure disconnect segment;

a drill collar segment;

an orienting tool segment;

a reamer segment; and

a mud motor segment.

4. The system for drilling a cavity in a medium of claim 1, wherein the first cross section is substantially symmetrical about at least one of a first vector in the first lateral direction and a second vector in a lateral direction substantially perpendicular to the first lateral direction.

5. The system for drilling a cavity in a medium of claim 1, wherein the first cross section at least partially defines at least one of a first hollow portion of the first length of chassis and a second hollow portion of the first length of chassis.

6. The system for drilling a cavity in a medium of claim 1, wherein the bending anisotropy of the first longitudinal segment is less than about 50 percent.

7. The system for drilling a cavity in a medium of claim 1, wherein the bending anisotropy of the first longitudinal segment is about 50 percent.

8. The system for drilling a cavity in a medium of claim 1, wherein the drill bit comprises a coring bit.

9. The system for drilling a cavity in a medium of claim 1, wherein the system further comprises:

a rotational motion source; and

a drill pipe, wherein;

the drill pipe is operably coupled with the rotational motion source;

the drill pipe is coupled with the bottom hole assembly;

the drill pipe has a second cross section; and

the second cross section is configured such that the portion of the drill pipe has a greater stiffness in a second lateral direction than in a lateral direction different than the second lateral direction.

10. A method for drilling a cavity in an earthen medium, wherein the method comprises:

providing a bottom hole assembly, wherein the bottom hole assembly comprises;

at least a first longitudinal segment, wherein;

the at least first longitudinal segment comprises a first length of chassis having a first cross section; and

the first cross section is configured such that the at least first longitudinal segment has a greater stiffness in a first lateral direction than in a lateral direction different than the first lateral direction resulting in a bending anisotropy; and

at least one drill bit, wherein the at least one drill bit is coupled with the at least first longitudinal segment;

providing a rotational motion source;

coupling, operably, the rotational motion source with the bottom hole assembly;

rotating the bottom hole assembly with the rotational motion source; and

a second longitudinal segment, wherein;

the second longitudinal segment comprises a second length of chassis having a second cross section; and

the second cross section is configured such that the second longitudinal segment has a greater stiffness in a second lateral direction than in a lateral direction different than the second lateral direction.

11. The method for drilling a cavity in a medium of claim 10, wherein coupling, operably, the rotational motion source with the bottom hole assembly comprises:

coupling, operably, the rotational motion source with a drill pipe;

coupling the drill pipe with the bottom hole assembly, wherein;

the drill pipe is operably coupled with the rotational motion source;

the drill pipe is coupled with the bottom hole assembly;

the drill pipe has a second cross section; and

the second cross section is configured such that the portion of the drill pipe has a greater stiffness in a second lateral direction than in a lateral direction different than the second lateral direction.

12. The method for drilling a cavity in a medium of claim 10, wherein the bending anisotropy of the first longitudinal segment is less than about 50 percent.

13. The method for drilling a cavity in a medium of claim 10, wherein the bending anisotropy of the first longitudinal segment is about 50 percent.

14. The method for drilling a cavity in a medium of claim 10, wherein the method further comprises:

providing the bottom hole assembly with a plurality of longitudinal segments;

running with a computer a series of simulation to identify at least one segment among the plurality of longitudinal segments that will be configured such that it has a greater stiffness in a first lateral direction than in a lateral direction different than the first lateral direction;

assigning a determined bending anisotropy to each of the at least one segment; and

configuring each of the at least one segment according to the assigned bending anisotropy.