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, 1997
Filed:
Dec. 14, 1995
Thomas F Bailey, Pebblebrook, TX (US);
John E Campbell, Houston, TX (US);
Joseph V Hebert, Tomball, TX (US);
Smith International, Inc., Houston, TX (US);
Abstract
A two trip sidetrack casing milling apparatus for elongating and enlarging a previously formed window in a cased borehole in preparation for a subsequent sidetracking drilling operation is disclosed. The apparatus consists of three mills on a shaft, a first window mill is secured to an end of a shaft. The first window mill forms a diameter larger than a diameter of a subsequent sidetracking drill bit that is passed through the window. A second pilot mill is secured to the shaft and strategically positioned above the first window mill. The second pilot mill forms a diameter that is less than the diameter of the first window mill. A third watermelon mill is secured to the shaft and strategically positioned above the second pilot mill. The third watermelon mill forms a diameter that is at least the same diameter as the first window mill. The second, smaller in diameter pilot mill serves to move toward the window thereby straightening the shaft while further cutting a portion of the casing surrounding the window thus assuring a more stable and accurate sidetrack direction. The third watermelon mill serves to dregs the window in the casing after the first window mill and the second pilot mill pass through the casing.