Thermally Stable Synthetic Diamond Drill Bit Proves Effective in Gulf Coast

Abstract

ABSTRACT A new thermally stable diamond cutter has proven effective in drilling medium to hard limestone and moderately abrasive sand. This new type of diamond is called "Ballas" which is a synthetic polycrystalline diamond. Ballas can be thought of as a more refined, or pure, polycrystalline diamond compact cutter which is free of foreign material within or attached to the diamond mass. The Ballas cutter is thermally stable up to 1200 degrees C compared to a conventional polycrystalline diamond compact which is only thermally stable up to 750 degrees C. This additional temperature resistance allows the use of self sharpening polycrystalline diamond to be used in harder, more abrasive formations which cannot be cut with the present diamond compact material. The use of the Ballas material has shown significant rate of penetration advantage in drilling the carbonate formations of East Texas and the depleted sands of So. Louisiana. Along with the success, present bit designs have experienced some problems drilling some of the clean plastic shales common on the Gulf Coast.