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:
Aug. 19, 2003
Filed:
Feb. 11, 2002
Steven James Hart, Bath, GB;
Graham R. Watson, Frampton on Severn, GB;
Grant Prideco, L.P., Houston, TX (US);
Abstract
A method to design a bi-center drill bit designed to drill out the cement and other material in the casing and then proceed to drill out the full gauge drilling diameter borehole with a diameter greater than the inside of the casing. The bi-center drill bit has a pilot section on the end of the bit body, an eccentric reamer section and a plurality of cutting elements on the pilot section. The design method comprises the steps of: defining a first center of rotation of the pilot section about the longitudinal axis, defining a radius of rotation R of the drill bit about the first center of rotation, defining a second center of rotation of the pilot section spaced apart from the first center of rotation by a distance D, defining a radius of rotation R of the drill bit about the second center of rotation, and setting the relationship between D, R and R such that R is less than the sum of R and D.