Jim Dahlem, Robert Gum and Bill Stark, Halliburton Energy Services

Roller cone bits have long dominated the drilling in the Spraberry field of West Texas. Experience and/or drilling log information have indicated that the formation is typically drilled with an insert type roller cone bit. Conical type insert bits are usually chosen because of the durability of their cutting structure. Typical intervals are from the surface casing to 9000 ft. The formations are usually drilled with two to three insert bits. Conical type insert bits, IADC 527 and 537, are usually chosen because of the durability of their cutting structure in drilling interbedded shale and limestone. Development and applications of a new type of fixed cutter bit, which is able to drill very efficiently through interbedded formations, incorporates new cutter technology with enhanced drillability, durability, and reduced vibration. Trials show an increase in penetration rates compared to the best roller cone run in the field.