Brian Solomon Ballard

US Patent:

8162081, Apr 24, 2012

Filed:

Aug 14, 2009

Appl. No.:

12/541591

Inventors:

Brian D. Ballard - La Porte TX, US
William W. King - Houston TX, US

Assignee:

Varel International Ind., L.P. - Carrollton TX

International Classification:

E21B 10/26
E21B 7/00

US Classification:

1753252, 175 57, 175406

Abstract:

A force balanced asymmetric drilling reamer comprising a plurality of blades, each blade having at least one cutter section and a gage section. The cutter section is designed to have a plurality of cutting devices for cutting through swelling formations and cutting free sloughing formations. The gage section has a full bore diameter with gage elements flushly coupled to gage section's outer surface. The blades may be curve/concave shaped or boomerang/chevron shaped, which thereby agitate the cutting beds. At least a portion of the drilling reamer's diameter is incrementally force balanced, starting from the outermost diameter, so that the net radial force is less than 10% of weight on bit with respect to the center of rotation. This balancing allows a greater cutter longevity and provides for a better wellbore condition. Optionally, at least a portion of the drilling reamer's surface may be treated by nitriding for repelling the cuttings.