The Positive Effects of Side Rake in Oilfield Bits Using Polycrystalline Diamond Compact Cutters

The main problem of polycrystalline diamond compact (PDC) bits drilling soft or plastic formation was identified as bit balling. Laboratory tests of a single compact cutting plastic shale under confining pressure with a load dynamometer and high speed photography were studied. New style drill and core bits built with side rake orientation along with previous style drill and core bits without side rake features were field tested and observed in the same drill hole or in the same formation. It was concluded that bits with side rake features can enhance the bit cleaning by mechanical cleaning action and. therefore, improve the bit performance in soft or plastic formations. 4 refs.