Throughout the history of oilfield drilling, workers have tried to improve drill bit mechanical efficiency. Various cutting theories, designs and materials have been implemented to increase ROP, wear resistance and overall bit life. The advent of the PDC cutter in the mid 1970’s started the gradual movement away from the roller cone bit to the shear cutter bit. The geometry of the PDC (Poly-Crystalline Diamond Compact) cutter changed the cutting mechanics from a point load or crushing of the rock to a transverse shearing motion. PDC bits have a number of advantages over roller cone bits in some environments and in many applications significantly outperform them. However PDC bits in geothermal drilling remains a field of relatively limited experience and is an area where PDC fixed cutter bits underperform compared to roller cone bits. A new, hard, thick, shaped Stinger™ PDC has been invented that aims to provide a link between crushing and shearing of rock to improve both ROP and overall cutter life. This paper describes the testing of such a cutter and preliminary work on Stinger populated drill bits aimed to enhance ROP in geothermal and EGS applications.

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