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:
Jan. 20, 1987
Filed:
Sep. 09, 1985
Georges Obrecht, Seyssins, FR;
Claude Dreuilhe, Saint Ismier, FR;
Alsthom, , FR;
Abstract
In a method of measuring azimuth for non-vertical drilling, during rotation of the drill pipe string two components of the magnetic field are measured continuously within a cylindrical section of the drill pipe string. This section is fabricated from the ferromagnetic steel usually employed for fabricating the drill pipes. The two components are measured by a magnetometer and lie along two axes perpendicular to the axis of the section and rotating with it. At the moment when the component of the acceleration due to gravity is maximum along one of these two axes, an accelerometer device commands the calculation and recording of the ratio of the two measured components of the magnetic field. On the basis of the value thus recorded, the measured inclination of the drill pipe string and the local inclination of the magnetic field, the azimuth of the drill pipe string relative to magnetic north is calculated. The method may be used for the continuous determination of the position of a drilling tool during the progress of drilling along a curve.