One of the main challenges drilling within the Troll field, offshore Norway is maintaining a high Rate of Penetration (ROP) while drilling through hard calcite cemented stringers (Jones et al. 2008a; Gunderson et al. 2008). The calcite distribution in this field is complex and can be difficult to predict, while it is easy to maintain a high ROP when drilling the sand sections between the stringers. Early wear or damage to the cutting structure limits the bit's ability to apply sufficient point loading to efficiently cut through the calcite and remaining lithologies, so the key aspects in solving this challenge is to retain the sharpness of the Polycrystalline Diamond Compact (PDC) cutters and minimize the risk of impact damage when hitting these thin inter-bedded stringers at high penetration rates. Following an in-depth study of the application, the drill bit design evolved following several iterations that included computational fluid dynamics to optimize fluid impingement angles and reduce fluid induced shear stress on both the bit body and cutter substrates. Torque control components were introduced to improve the design's response to weight-on-bit, minimize stick-slip and improve directional response. Detailed laboratory tests were conducted to investigate a new edge preparation applied to a new thermally stable PDC cutter, and the cutter-rock interaction was modeled to investigate complex wear, involving impact, abrasion and thermal mechanisms, while drilling these highly inter-bedded formations. The results of this research led to new cutter and bit technologies which have proven that the combination of improved thermal resistance and more efficient cutter geometry enables the cutters to stay sharp while drilling through the hardest stringers and maintain greater durability to complete the section. The improved designs have now drilled further and faster than any previous attempts, resulting in significant cost savings for the operator.