Evaluating a condition of a downhole component of a drillstring
First Claim
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;
determining a number rotations of the component at the selected depth;
associating the number of rotations of the component at the selected depth with the bending moment on the component at the selected depth; and
estimating the condition of the component using the number of rotations at the bending moment;
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;
wherein the condition is at least one of;
i) accumulated fatigue of the component; and
ii) estimated remaining useful life of the component.
2 Assignments
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Accused Products
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.
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Citations
15 Claims
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1. A method for evaluating a condition of a downhole component of a drilling assembly in a borehole, the method comprising:
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estimating a bending moment on the component at a selected depth along the borehole; determining a number rotations of the component at the selected depth; associating the number of rotations of the component at the selected depth with the bending moment on the component at the selected depth; and estimating the condition of the component using the number of rotations at the bending moment; 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; wherein the condition is at least one of;
i) accumulated fatigue of the component; and
ii) estimated remaining useful life of the component. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A system for conducting drilling operations, the system comprising:
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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 a 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; determine a number of rotations of the component at the selected depth using information from the second sensor; associate the number of rotations of the component at the selected depth with the bending moment on the component at the selected depth; and estimate the condition of the component using the number of rotations at the bending moment; 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; wherein the condition is at least one of;
i) accumulated fatigue of the component; and
ii) estimated remaining useful life of the component. - View Dependent Claims (10, 11, 12, 13, 14, 15)
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Specification