Carbonate rock is a predominant Middle Eastern geologic feature. Penetration of 16-in. hole sections through carbonates in the Kuwait northern field has required use of more than one bit. The full-length paper describes an engineering methodology that produced bit designs that can complete the entire 16-in. section with a single bit. The new design is the result of a symptom/cause/remedy approach that identifies causes of unsatisfactory bit life and suggests remedial solutions.