Patricia A Harrell

US Patent:

53722108, Dec 13, 1994

Filed:

Oct 12, 1993

Appl. No.:

8/136442

Inventors:

Patricia N. Harrell - Houston TX

Assignee:

Camco International Inc. - Houston TX

International Classification:

E21B 1000

US Classification:

175431

Abstract:

In a rolling cutter drill bit the distribution of the inserts on each rolling cutter is arranged to form a more rounded borehole corner to reduce concentrated side forces and to facilitate directional drilling while minimising gauge wear. Each rolling cutter includes a transition row of inserts which is intermediate the gauge cutting row and bottom cutting row and which drill neither the gauge of the borehole nor the hole bottom, but drill a rounded transition area between the vertical side wall and borehole bottom. The invention provides the ratios between certain key dimensions of the insert rows, such ratios being selected to determine the roundness of the corner of the borehole in such manner as to improve the ability of the bit to drill curved boreholes. These key dimensions include the relative diameters and spacing of the insert rows, the relative diameters of the inserts, and their relative angular orientations with respect to the longitudinal axis of the drill bit.

Address:

6838 Orville St, Houston, TX 77028

VIN:

1N4BA41E27C857894

Make:

NISSAN

Model:

MAXIMA

Year:

2007