Publications

The challenges in drilling hard and abrasive formation have been studied over decades by drill bit designers to improve drilling efficiency while reducing trips to save total drilling cost. The evolution of Poly-crystalline Diamond Compact (PDC) cutter technology and hybrid drill bit design, which combined PDC and diamond impregnated bit, extends bit durability and expands the application range of drilling in highly compressive strength and highly abrasivity lithologies. By having dual cutting structure of shearing with PDC cutter and grinding with impregnated diamond as rock failure mechanism, such design maximizes drilling efficiency in these harsh environments. The first hybrid drill bit run in Indonesia was utilized in the Timor Sea and recorded the highest Rate of Penetration (ROP) in the field. The 8-blade, 13 mm cutter drill bit successfully drilled into the Plover Formation which is known for having very hard and abrasive formation consisting of interbedded shale and sandstone with unconfined compressive strength of more than 25 kpsi. After the first successful run, several hybrid drill bit runs took place in the same field. In this application, the use of hybrid drill bit technology improves ROP performance and reduces overall cost. Previously, it would typically require a number of PDC, roller cone, or impregnated bits with a turbine drive system to reach target depth. At the design stage of the hybrid drill bit, PDC cutter technology and innovation played an important role in the design process. Cutter technology was specifically optimized to provide superior abrasion and thermal resistance, selected to overcome the high abrasivity of the formations. With higher thermal resistance of PDC cutter properties, a hybrid drill bit cutter can withstand a higher temperature while maintaining its microstructure properties to avoid premature cutter damage which in turn extends bit durability.