METHOD FOR TESTING NON-UNIFORM LOADS IN PIPES

• US 20150101397A1
• Filed: 12/22/2011
• Published: 04/16/2015
• Est. Priority Date: 12/22/2011
• Status: Active Grant

• Current Assignee: Petroleo Brasileiro SA - Petrobras
• Original Assignee: Petroleo Brasileiro SA - Petrobras
• Inventors: Poiate Junior, Edgard, Pimentel Neto, Jose Nunes, Medeiros, Fernando Antonio Santos, Da Costa, Alvaro Maia, Falco, Jose Luiz, Dos Santos Amaral, Claudio, Da Rocha, Renato Seixas
• Granted Patent: US 10,078,042 B2
• Time in Patent Office: Days
• US Class Current: 73/49.5
• CPC Class Codes: E21B 47/007 Measuring stresses in a pipe string or casing for locating blocked portions of pipes E21B47/09
• CPC Class Codes: E21B 49/003 by analysing drilling variables or conditions E21B49/005 takes precedence; systems specially adapted for monitoring a plurality of drilling variables or conditions E21B44/00
• CPC Class Codes: G01M 5/0058 of elongated objects, e.g. pipes, masts, towers or railways
• CPC Class Codes: G01N 2203/0042 Pneumatic or hydraulic means
• CPC Class Codes: G01N 2203/0246 Special simulation of "in situ" conditions, scale models or dummies
• CPC Class Codes: G01N 2203/0274 Tubular or ring-shaped specimens
• CPC Class Codes: G01N 3/12 Pressure testing

Abstract

The present invention refers to a method wherein a test body is assembled in specific configurations to be submitted to testing in a conventional hydrostatic chamber. The method calls for assembling a test body that simulates cementing failures, the presence of stress anisotropy and a borehole of irregular geometry, by pressurizing said test body in a conventional hydrostatic chamber. The uniform forces are distributed circumferentially around a casing stream in a non-uniform way, simulating operating conditions that are as close as possible to reality, enabling an analysis of how the structure reacts in scenarios similar to actual conditions.

Claims

1. METHOD FOR TESTING NON-UNIFORM LOADS ON PIPES, which employs a conventional hydrostatic chamber (200) provided with a test body (10), characterised by being comprised of the following steps:

assembling test bodies (10) of specific configurations, simulating the non-uniform loads generated by situations such as cementing failures, the presence of stress anisotropy in the borehole and irregular geometry;

placing said test body (10) in a conventional hydrostatic chamber (200) and pressurizing said chamber;

applying uniform stresses generated by a hydrostatic chamber (200) and by compressors (15) and (15b), in such a way as to enable changing the pressure in the simulated failure area and the inside the casing string, reproducing a controlled scenario of non-uniform forces (N) acting on the casing under (100) under analysis;

measuring the displacement and strain using sensor elements placed in the pipe representing the casing string (100).

2. METHOD FOR TESTING NON-UNIFORM LOADS ON PIPES according to claim 1, characterised by the test body (10) being comprised of two pipes placed one inside the other and flanged (102) to each other so as to create a chamber between the outer surface (101) of the inner pipe and the inner surface of the outer pipe, said chamber being suitable for filling with cement, interspersed with at least one previously determined empty section (13);

the inner pipe represents a section of casing string (100) placed within a containment tube (12), and the empty spaces (13) simulate cementing failures.

3. METHOD FOR TESTING NON-UNIFORM LOADS ON PIPES according to claim 2, characterised by the empty spaces (13) being optionally fitted with a means of access (13a) through the casing string (100), through which pressure can applied by using an air compressor or regular pump (15)

4. METHOD FOR TESTING NON-UNIFORM LOADS ON PIPES according to claim 1, characterised by the test body (10) being fitted with semi-spherical flanges (103) at both ends, and with a means of access (16) through the casing string (100), through which pressure can be applied inside the casing string (100) using an air compressor or regular pump (15b).

5. METHOD FOR TESTING NON-UNIFORM LOADS ON PIPES according to claim 1, characterised by the test body (10) being comprised of a section of casing string (100) surrounded by commonly used cementing material (11), which in turn is supported by a containment tube (12) comprised of thin metal that offers little resistance, acting merely as a means to support the cementing layer (11) of the test body (10).

6. METHOD FOR TESTING NON-UNIFORM LOADS ON PIPES according to claim 1, characterised by the test body (10) being prepared from a section of casing string (100) placed within the containment tube (12) and centered with respect to the containment tube (12).

7. METHOD FOR TESTING NON-UNIFORM LOADS ON PIPES according to claim 1, characterised by the test body (10) being prepared from a section of casing string (100) placed within the containment tube (12) and not centered with respect to the containment tube (12).

8. METHOD FOR TESTING NON-UNIFORM LOADS ON PIPES according to claim 2, characterised by having a containment tube (12) with a circular cross-section.

9. METHOD FOR TESTING NON-UNIFORM LOADS ON PIPES according to claim 2, characterised by the containment tube (12) alternatively having an oval cross-section.

10. METHOD FOR TESTING NON UNIFORM LOADS ON PIPES according to claim 2, characterised by the empty space (13) being shaped by placing a balloon with air or fluid, or any other filler material that will not influence the load transfer effects, such as polyurethane, polyethylene or polystyrene foam, or frames made of wood, bamboo or other materials, in the chamber created between the pipes prior to cementing.

11. METHOD FOR TESTING NON-UNIFORM LOADS ON PIPES according to claim 2, characterised by the emptied portion (13) comprising between 1% and 100% of the total perimeter of the casing string (100).

12. METHOD FOR TESTING NON-UNIFORM LOADS ON PIPES according to claim 2, characterised by the emptied portion (13) being disposed concentrically around a segment of casing string.

13. METHOD FOR TESTING NON-UNIFORM LOADS ON PIPES according to claim 2, characterised by the emptied portion (13) being alternatively disposed in segments symmetrically distributed along the perimeter.

14. METHOD FOR TESTING NON-UNIFORM LOADS ON PIPES according to claim 2, characterised by the emptied portion (13) being alternatively disposed in segments asymmetrically distributed along the perimeter.

15. METHOD FOR TESTING NON-UNIFORM LOADS ON PIPES according to claim 1, characterised by the quality of the cementing changing in a controlled way in specific regions, altering the percentage of the components it is made up of or its porosity.

16. METHOD FOR TESTING NON-UNIFORM LOADS ON PIPES according to claim 2, characterised by the containment tube (12) being built of nonstructural metal, and the emptied portions (13) being fitted with a welded piece of rolled sheet (14) that plays a structural role.