The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Feb. 28, 2017
Filed:
Dec. 02, 2008
Applicant:
Age Kyllingstad, Algard, NO;
Inventor:
Age Kyllingstad, Algard, NO;
Assignee:
NATIONAL OILWELL VARCO, L.P., Houston, TX (US);
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
E21B 44/00 (2006.01);
U.S. Cl.
CPC ...
E21B 44/00 (2013.01);
Abstract
A method and apparatus for damping stick-slip oscillations in a drill string. In one embodiment a method includes damping the stick-slip oscillations using a drilling mechanism at the top of said drill string. The speed of rotation of the drilling mechanism is controlled using a PI controller. The control is characterized by tuning the PI controller so that the drilling mechanism absorbs most torsional energy from the drill string at a frequency that is at or near a frequency of the stick-slip oscillations.