Cutting Structures
In 1909, when roller cone bits were introduced into the oilfield, the drag bit
was replaced by the roller cone’s steel tooth cutting structure. These steel
(milled) teeth have undergone changes in height, number per cone, and
thickness, to accommodate the various types of formations.
When harder formations tended to “eat up” the steel teeth, a different
cutting structure was needed, and in 1949 the first insert bit was used.
Introduced by Hughes Tool Company and nicknamed the “The Chert Bit”,
it brought on-bottom drilling hours up from 5 hours to 30 hours or more.
Many of the design features in the milled tooth bits were incorporated into
insert bits.
In 1909, when roller cone bits were introduced into the oilfield, the drag bit
was replaced by the roller cone’s steel tooth cutting structure. These steel
(milled) teeth have undergone changes in height, number per cone, and
thickness, to accommodate the various types of formations.
When harder formations tended to “eat up” the steel teeth, a different
cutting structure was needed, and in 1949 the first insert bit was used.
Introduced by Hughes Tool Company and nicknamed the “The Chert Bit”,
it brought on-bottom drilling hours up from 5 hours to 30 hours or more.
Many of the design features in the milled tooth bits were incorporated into
insert bits.
