Evaluating a Condition of a Downhole Component of a Drillstring

• US 20150075274A1
• Filed: 09/16/2013
• Published: 03/19/2015
• Est. Priority Date: 09/16/2013
• Status: Active Grant

• Current Assignee: Baker Hughes, a GE Company, LLC (Baker Hughes Company)
• Original Assignee: Baker Hughes Incorporated (Baker Hughes Company)
• Inventors: Trichel, Donald Keith, Kpetehoto, Franck T., ElKamel, Abdallah Ahmed, Janwadkar, Sandeep S., Chandrasekaran, Sridharan
• Granted Patent: US 9,845,671 B2
• Time in Patent Office: Days
• US Class Current: 73/152.48
• CPC Class Codes: E21B 47/007 Measuring stresses in a pipe string or casing for locating blocked portions of pipes E21B47/09

Abstract

Methods, systems and products for evaluating a downhole component condition for a drilling assembly in a borehole. Methods include estimating a bending moment on the component at a selected depth along the borehole; estimating a number of rotations of the component at the selected depth; and estimating the condition of the component using the estimated bending moment and the estimated number of rotations at the selected depth. Estimated bending moment may be derived from a borehole model using an estimated deviation on a selected length of the borehole about the selected depth. The condition may be accumulated fatigue or estimated remaining useful life. Estimating the condition may include tracking a total estimated number of rotations wherein the component is subjected to bending moment values in a corresponding moment window, which may be greater than a predetermined threshold bending moment. Weight factors may be associated with at least one moment window.

Claims

1. A method for evaluating a condition of a downhole component of a drilling assembly in a borehole, the method comprising:

estimating a bending moment on the component at a selected depth along the borehole;

estimating a number of rotations of the component at the selected depth; and

estimating the condition of the component using the estimated bending moment and the estimated number of rotations at the selected depth.

2. The method of claim 1 further comprising deriving the estimated bending moment using an estimated deviation on a selected length of the borehole about the selected depth.

3. The method of claim 2 further comprising deriving the estimated deviation from a borehole model.

4. The method of claim 1, wherein the method further comprises deriving the estimated location of the component in the borehole using an axial offset of the component from a distal end of the drilling assembly.

5. The method of claim 1, wherein the condition is at least one of:

i) accumulated fatigue of the component; and

ii) estimated remaining useful life of the component.

6. The method of claim 1, wherein a spectrum of bending moment values is divided into a number of mutually exclusive moment windows, and wherein estimating the condition comprises tracking a total estimated number of rotations wherein the component is subjected to bending moment values in a corresponding moment window.

7. The method of claim 6, wherein at least one selected window is greater than a predetermined threshold bending moment.

8. The method of claim 6, further comprising:

associating a weight factor with at least one moment window; and

using at least the weight factor and the total estimated number of rotations wherein the component is subjected to the bending moment values in the corresponding moment window to estimate the condition of the component.

9. The method of claim 1, further comprising estimating the condition of the component while conducting drilling operations in the borehole.

10. The method of claim 1 further comprising:

deriving the estimated bending moment from a borehole model using an estimated deviation on a selected length of the borehole about the selected depth and dimensions of the component; and

deriving the estimated location of the component in the borehole using an axial offset of the component from a distal end of the drilling assembly;

wherein a spectrum of bending moment values is divided into a number of mutually exclusive moment windows, and estimating the condition comprises tracking a total estimated number of rotations wherein the component is subjected to bending moment values in a corresponding moment window and wherein at least one selected window is greater than a predetermined threshold bending moment; and

wherein the component is at the bottom hole assembly and the condition is at least one of;

i) accumulated fatigue of the component; and

ii) estimated remaining useful life of the component.

11. A system for conducting drilling operations, the system comprising:

a drilling assembly configured to be conveyed into a borehole, the drilling assembly comprising at least one component;

a first sensor associated with the drilling assembly and responsive to the depth of the component along the borehole;

a second sensor associated with the drilling assembly and responsive to rotation of the component; and

at least one processor configured to;

determine a depth of the component along the borehole using information from the first sensor;

estimate a bending moment on the component at the depth;

estimate a number of rotations of the component at the selected depth using information from the second sensor; and

estimate the condition of the component using the estimated bending moment and the estimated number of rotations at the selected depth.

12. The system of claim 11, wherein the processor is further configured to derive the estimated location of the component using an axial offset of the component from a distal end of the drilling assembly.

13. The system of claim 11, wherein the processor is further configured to derive the estimated bending moment using an estimated deviation on a selected length of the borehole about the depth.

14. The system of claim 13, wherein the processor is further configured to derive the estimated deviation from a borehole model.

15. The system of claim 11, wherein the processor is further configured to separate a spectrum of bending moment values into a number of mutually exclusive moment windows, and track a total estimated number of rotations wherein the component is subjected to bending moment values in at least one selected moment window.

16. The system of claim 15, wherein the at least one selected window is greater than a predetermined threshold bending moment.

17. The system of claim 15, wherein the processor is further configured to:

associate a weight factor with the at least one selected moment window; and

use at least the weight factor and the total estimated number of rotations wherein the component is subjected to the bending moment values in the corresponding moment window to estimate the condition of the component.

18. The system of claim 11, wherein the processor is further configured to estimate the condition of the component before the component is removed from the borehole.

19. A non-transitory computer-readable medium product for evaluating a condition of a downhole component of a drilling assembly in a borehole, the product accessible to at least one processor, the computer readable medium including instructions that enable the at least one processor to:

estimate a bending moment on the component at a selected depth along the borehole;

estimate a number of rotations of the component at the selected depth; and

estimate the condition of the component using the estimated bending moment and the estimated number of rotations at the selected depth.