Roller cone drill bits are provided with cutting elements and cutting structures optimized for efficient drilling of soft and medium formations interspersed with hard stringers. The cutting elements and cutting structures may be satisfactorily used to drill downhole formations with varying amounts of hardness. The cutting elements and cutting structures may also be optimized to reduce tracking and increase wear resistance.
RELATED APPLICATION
This continuation-in-part application claims the benefit of U.S. Provisional Patent Application Ser. No. 60/549,354 entitled "Roller Cone Drill Bits with Enhanced Cutting Elements and Cutting Structures" filed Mar. 2, 2004.
This application is a continuation-in-part application of U.S. Continuation patent application Ser. No. 10/189,305 entitled "Roller-Cone Bits, Systems, Drilling Methods, and Design Methods with Optimization of Tooth Orientation" filed on Jul. 2, 2002, now abandoned, which is a continuation application of U.S. Continuation patent application Ser. No. 09/629,344 entitled "Roller-Cone Bits, Systems, Drilling Methods and Design Methods with Optimization of Tooth Orientation" filed Aug. 1, 2000, now U.S. Pat. No. 6,412,577, which is a continuation of U.S. patent application Ser. No. 09/387,304 entitled "Roller-Cone Bits, Systems, Drilling Methods, and Design Methods with Optimization of Tooth Orientation" filed Aug. 31, 1999, now U.S. Pat. No. 6,095,262, which claims priority from U.S. Provisional Application No. 60/098,442 filed Aug. 31, 1998.
This application is copending to U.S. Continuation patent application Ser. No. 10/756,109 entitled "Roller-Cone Bits, Systems, Drilling Methods, and Design Methods with Optimization of Tooth Orientation" filed Jan. 13, 2004.
This application is also to continuation application of U.S. patent application Ser. No. 10/766,494 entitled "Roller-Cone Bits, Systems, Drilling Methods, and Design Methods with Optimization of Tooth Orientation" filed Jan. 28, 2004, now abandoned.
