Blowout preventers and methods of use

• US 7,814,979 B2
• Filed: 05/05/2008
• Issued: 10/19/2010
• Est. Priority Date: 04/25/2006
• Status: Active Grant

• Current Assignee: National Oilwell Varco LP (NOV, Inc.)
• Original Assignee: National Oilwell Varco LP (NOV, Inc.)
• Inventors: Springett, Frank Benjamin, Brugman, James D.
• Primary Examiner(s): BOMAR, THOMAS S
• Application Number:
  US12/151,279
• Publication Number:
  US 20080286534A1
• Time in Patent Office: 897 Days
• Field of Search: 166/298, 166/55, 836/93, 836/94
• US Class Current: 166/298
• CPC Class Codes: E21B 33/063 for shearing drill pipes cutting of wireline E21B29/04
• CPC Class Codes: Y10T 428/24777 Edge feature
• CPC Class Codes: Y10T 83/0581 Cutting part way through from opposite sides of work
• CPC Class Codes: Y10T 83/0596 Cutting wall of hollow work
• CPC Class Codes: Y10T 83/75 With or to tool guide
• CPC Class Codes: Y10T 83/9447 Shear type

Abstract

Methods and apparatuses for severing a wellbore tubular, the apparatus, in certain aspects, including: a first member movable toward a tubular to be severed; a second member with a second blade disposed opposite to the first member and movable toward the tubular; a first blade on the first member having a projection projecting from a center of a blade body with point structure on the projection for puncturing the tubular and cutting surfaces on the projection for cutting the tubular; and cutting surfaces, as needed, on the blade body adjacent the projection for cutting the tubular.

Claims

1. A method for severing a tubular, the tubular useful for wellbore operations, the method comprising

inserting a portion of a tubular into a tubular severing apparatus comprising a first member movable toward the tubular, a second member movable toward the tubular, the second member disposed opposite the first member, a first blade on the first member, the first blade comprising a first blade body, a first point structure on the first blade body for contacting and puncturing the tubular, first cutting surfaces on the first blade body spaced-apart and adjacent the first point structure and for cutting the tubular, the first point structure projecting sufficiently from the first blade body so that the first point structure can contact the tubular and puncture the tubular before the first cutting surfaces of the first blade body cut the tubular, and a second blade on the second member, the second blade comprising a second blade body, a second point structure on the second blade body for contacting and puncturing the tubular, second cutting surfaces on the second blade body spaced-apart and adjacent the second point structure and for cutting the tubular, the second point structure projecting sufficiently from the second blade body so that the second point structure can contact the tubular and puncture the tubular before the second cutting surfaces of the second blade body cut the tubular,

moving the first blade toward the tubular to bring the first point structure into contact with an outer surface of the tubular,

moving the first blade so that the first point structure punctures into the tubular and goes through the tubular,

moving the second blade toward the tubular to bring the second point structure into contact with an outer surface of the tubular,

moving the second blade so that the second point structure punctures into the tubular and goes through the tubular,

wherein each of the two point structures contact the tubular substantially simultaneously and puncture the tubular substantially simultaneously,

following puncturing of the tubular by the point structures, pushing apart portions of the tubular adjacent each point structure as the point structures move toward each other,

following puncturing of the tubular by both point structures, moving the first blade and the second blade to sever the tubular with the first and second cutting surfaces,

wherein each point structure has a point and each point passes completely through the tubular prior to complete severing of the tubular.

2. The method of claim 1 wherein the tubular is from the group consisting of casing, drill pipe, drill collar, and tool joint.

3. The method of claim 1 wherein the first point structure is above the second point structure.

4. A method for severing a tubular, the tubular useful for wellbore operations, the method comprising

inserting a portion of a tubular into a tubular severing apparatus comprising a first member movable toward the tubular, a second member movable toward the tubular, the second member disposed opposite the first member, a first blade on the first member, the first blade comprising a first blade body, a first point structure on the first blade body for contacting and puncturing the tubular, first cutting surfaces on the first blade body spaced-apart and adjacent the first point structure and for cutting the tubular, the first point structure projecting sufficiently from the first blade body so that the first point structure can contact the tubular and puncture the tubular before the first cutting surfaces of the first blade body cut the tubular, and a second blade on the second member, the second blade comprising a second blade body, a second point structure on the second blade body for contacting and puncturing the tubular, second cutting surfaces on the second blade body spaced-apart and adjacent the second point structure and for cutting the tubular, the second point structure projecting sufficiently from the second blade body so that the second point structure can contact the tubular and puncture the tubular before the second cutting surfaces of the second blade body cut the tubular,

moving the first blade toward the tubular to bring the first point structure into contact with an outer surface of the tubular,

moving the first blade so that the first point structure punctures into the tubular and goes through the tubular,

moving the second blade toward the tubular to bring the second point structure into contact with an outer surface of the tubular,

moving the second blade so that the second point structure punctures into the tubular and goes through the tubular,

following puncturing of the tubular by both point structures, moving the first blade and the second blade to sever the tubular with the first and second cutting surfaces

following puncturing of the tubular by the point structures, pushing apart portions of the tubular adjacent each point structure as the point structures move toward each other, and

said pushing apart occurring before cutting of the tubular by the first cutting surfaces and by the second cutting surfaces.

5. The method of claim 4 wherein each of the two point structures contact the tubular substantially simultaneously and puncture the tubular substantially simultaneously.

6. The method of claim 4 wherein the tubular is from the group consisting of casing, drill pipe, drill collar, and tool joint.

7. The method of claim 4 further comprising

severing the tubular with the cutting surfaces occurs after said pushing apart.

8. The method of claim 4 wherein each point structure has a point and each point passes completely through the tubular prior to severing of the tubular by the cutting surfaces.

9. The method of claim 4 wherein the first point structure is above the second point structure.

10. A tubular severing apparatus for severing a tubular used in wellbore operations, the tubular severing apparatus comprising

a first member movable toward the tubular,

a second member movable toward the tubular, the second member disposed opposite the first member,

a first blade on the first member, the first blade comprising a first blade body, a first point structure on the first blade body for contacting and puncturing the tubular, first cutting surfaces on the first blade body spaced-apart and adjacent the first point structure and for cutting the tubular,

the first point structure projecting sufficiently from the first blade body so that the first point structure can contact the tubular and puncture the tubular before the first cutting surfaces of the first blade body cut the tubular,

the second member having a second blade comprising a second blade body, a second point structure on the second blade body for contacting and puncturing the tubular, second cutting surfaces on the second blade body spaced-apart and adjacent the second point structure and for cutting the tubular,

the second point structure projecting sufficiently from the second blade body so that the second point structure can contact the tubular and puncture the tubular before the second cutting surfaces of the second blade body cut the tubular,

the first cutting surfaces and the second cutting surfaces positioned so that following puncturing of the tubular by both point structures, the cutting surfaces are movable to sever the tubular, and

the cutting surfaces positioned and configured for pushing apart portions of the tubular adjacent each point structure as the point structures are moved toward each other.

11. The tubular severing apparatus of claim 10 wherein each of the two point structures are movable to contact a tubular substantially simultaneously and puncture the tubular substantially simultaneously.

12. The tubular severing apparatus of claim 10 wherein each point structure has a point and each point can pass completely through the tubular prior to complete severing of the tubular.

13. The tubular severing apparatus of claim 10 wherein the first point structure is above the second point structure.