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:
Oct. 20, 2009
Filed:
May. 22, 2008
Erik P. Eriksen, Calgary, CA;
Michael E. Moffitt, Houston, TX (US);
Tommy M. Warren, Coweta, OK (US);
Erik P. Eriksen, Calgary, CA;
Michael E. Moffitt, Houston, TX (US);
Tommy M. Warren, Coweta, OK (US);
Tesco Corporation (US), Houston, TX (US);
Abstract
A bottom hole assembly is retrieved through a casing string by lightening the density of the drilling fluid in the casing string above the bottom hole assembly to a lesser density than the drilling fluid in the casing string annulus. The bottom hole assembly moves upward in the casing string in response to an upward force created by the different densities of fluid. While moving upward, less dense fluid being displaced by the upward movement of the bottom hole assembly flows from the casing string. When the bottom hole assembly stops moving upward, slips suspended it at that intermediate point in the casing string. The operator now lightens the density of the drilling fluid in the casing string below the bottom hole assembly, again creating an upward force on the bottom hole assembly that causes the bottom hole assembly to move upward in the casing string.