Method of drilling lateral wellbores from a slant well without utilizing a whipstock

• US 6,964,308 B1
• Filed: 10/08/2002
• Issued: 11/15/2005
• Est. Priority Date: 10/08/2002
• Status: Expired due to Fees

• Current Assignee: Effective Exploration LLC
• Original Assignee: CDX Gas LLC (EnerVest Ltd.)
• Inventors: Zupanick, Joseph A.
• Primary Examiner(s): Bagnell, David
• Assistant Examiner(s): Smith, Matthew J.
• Application Number:
  US10/267,426
• Time in Patent Office: 1,134 Days
• Field of Search: 175/61, 175/62, 175/74, 175/75, 166/117.5
• US Class Current: 175/61
• CPC Class Codes: E21B 7/067 with means for locking sections of a pipe or of a guide for a shaft in angular relation, e.g. adjustable bent sub

Abstract

In accordance with one embodiment of the present invention, a method for drilling a lateral wellbore from a slant well includes drilling the slant well below the surface of the earth such that the slant well is angled toward a first horizontal direction that coincides with a desired drilling direction for the lateral wellbore. The slant well has a borehole wall that includes a high side portion closest to the surface, a low side portion farthest from the surface, and two side portions between the high side portion and the low side portion. The method further includes disposing a casing string in the slant well, disposing a drill string having a bent sub, a mud motor, and a drill bit coupled at a lower end thereof in the casing string, and positioning the drill bit adjacent either one of the side portions or the low side portion. The method further includes drilling, from either the side portion or the low side portion, an intermediate wellbore with the drill bit, and drilling, from the intermediate wellbore, the lateral wellbore in the desired drilling direction.

Claims

1. A method for drilling a lateral wellbore from a slant well, comprising:

drilling the slant well below the surface of the earth, the slant well angled toward a first horizontal direction that generally coincides with a desired drilling direction for the lateral wellbore, the slant well having a borehole wall comprising;

a high side portion closest to the surface;

a low side portion farthest from the surface; and

two side portions between the high side portion and the low side portion;

disposing a drill string in the slant well, the drill string having a drill bit coupled at a lower end thereof;

positioning the drill bit in contact with one of the side portions;

drilling, from the side portion, an intermediate wellbore with the drill bit; and

drilling, from the intermediate wellbore, the lateral wellbore in the desired drilling direction.

2. The method of claim 1, wherein the high side portion, the low side portion, and the two side portions each comprise approximately a quarter of the perimeter of the borehole wall.

3. The method of claim 1, wherein each of the two side portions comprise a larger portion of the perimeter of the borehole wall than each of the high side and low side portions.

4. The method of claim 1, wherein drilling the intermediate wellbore comprises drilling the intermediate wellbore at an approximately ninety degree angle from the desired drilling direction of the lateral wellbore in a generally horizontal plane.

5. The method of claim 1, further comprising:

disposing a casing string in the slant well; and

disposing the drill string in the casing string.

6. The method of claim 5, further comprising disposing the casing string in the slant well such that an outer annulus is formed between the borehole wall of the slant well and an outer wall of the casing string, and disposing the drill string in the casing string such that an inner annulus is formed between an inner wall of the casing string and an outer wall of the drill string.

7. The method of claim 6, further comprising:

circulating a first fluid down an inner passage of the drill string;

circulating a second fluid down the inner annulus; and

retrieving a mixture of the first and second fluids through the outer annulus.

8. The method of claim 6, further comprising:

circulating a first fluid down an inner passage of the drill string;

circulating a second fluid down the outer annulus; and

retrieving a mixture of the first and second fluids through the inner annulus.

9. The method of claim 1, wherein the drill string further includes a bent sub at a lower end thereof.

10. The method of claim 1, wherein all of the drilling steps are performed without utilizing a whipstock.

11. A method for drilling a lateral wellbore from a slant well, comprising:

drilling the slant well below the surface of the earth, the slant well angled toward a first horizontal direction that generally coincides with a desired drilling direction for the lateral wellbore, the slant well having a borehole wall comprising;

a high side portion closest to the surface;

a low side portion farthest from the surface; and

two side portions between the high side portion and the low side portion;

disposing a drill string in the slant well, the drill string having a drill bit coupled at a lower end thereof;

positioning the drill bit in contact with the low side portion;

drilling, from the low side portion, an intermediate wellbore with the drill bit; and

drilling, from the intermediate wellbore, the lateral wellbore in the desired drilling direction.

12. The method of claim 11, wherein the high side portion, the low side portion, and the two side portions each comprise approximately a quarter of the perimeter of the borehole wall.

13. The method of claim 11, wherein each of the two side portions comprise a larger portion of the perimeter of the borehole wall than each of the high side and low side portions.

14. The method of claim 11, wherein the drill string further includes a bent sub at a lower end thereof.

15. The method of claim 11, wherein all of the drilling steps are performed without utilizing a whipstock.

16. The method of claim 11, further comprising:

disposing a casing string in the slant well; and

disposing the drill string in the casing string.

17. The method of claim 16, further comprising disposing the casing string in the slant well such that an outer annulus is formed between the borehole wall of the slant well and an outer wall of the casing string, and disposing the drill string in the casing string such that an inner annulus is formed between an inner wall of the casing string and an outer wall of the drill string.

18. The method of claim 17, further comprising:

circulating a first fluid down an inner passage of the drill string;

circulating a second fluid down the inner annulus; and

retrieving a mixture of the first and second fluids through the outer annulus.

19. The method of claim 17, further comprising:

circulating a first fluid down an inner passage of the drill string;

circulating a second fluid down the outer annulus; and

retrieving a mixture of the first and second fluids through the inner annulus.