Patent · US Active

Alternating frequency time domain approach to calculate the forced response of drill strings

US9000941B2 · kind B2 · utility

0Cited by

5References

24Claims

0Family size

Assignee

Baker Hughes Holdings LLC · US

Inventors

Andreas Hohl · Hannover, DE
Frank Schuberth · Hannover, DE
Hanno Reckmann · Wathlingen, DE

Key dates

Filing date	Feb 20, 2013
Grant date	Apr 7, 2015
Priority date	—
Expiry date	Sep 8, 2033

Classification

Technology area (CPC E)Fixed Constructions
CPC primaryE21B17/00
WIPO fieldCivil engineering
WIPO sectorOther fields

Abstract

A method for estimating a steady state response of a drill string in a borehole includes calculating a first displacement of the drill string in a frequency domain for a first excitation force frequency and a number of multiples of this frequency using an equation of motion of the drill string. The equation of motion has a static force component, an excitation force component, and a non-linear force component with respect to at least one of a deflection and a derivative of the deflection of the drill string. The method further includes: transforming the first displacement from the frequency domain into a time domain; calculating a non-linear force in the time domain; calculating a frequency domain coefficient derived from the calculated non-linear force in the time domain; and calculating a second displacement of the drill string in the frequency domain using the equation of motion and the frequency domain coefficient.

Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.