Abstract: Drilling deep formations in the Wenchang Block offshore of Western South China Sea with conventional PDC bits often resulted in severe abrasion and low rates of penetration (ROP) issues.Studies have been conducted to enhance ROPs by using innovative PDC bits with rotary cutters.By analyzing challenges in drilling operations in deep formations in the Wenchang Block,with considerations of formation properties and drill bit abrasion,the decision was made to use rotary cutters instead of fixed cutters in the highly abrasive shoulders of conventional PDC bits.With optimized distribution of rotary cutters, innovative PDC bits with rotary cutters were developed in deep formations drilling in the Wenchang Block.The newly-developed PDC bits with rotary cutters were deployed in three exploration wells in the Wenchang Block.Field application results showed that these bits can effectively enhance ROP with higher bit footage and outstanding abrasion-proof performances.Research results showed that innovative PDC bits with rotary cutters have outstanding aggressiveness and anti-abrasion performances.Since these bits can effectively enhance ROPs in deep formations of the Wenchang Block in the Western South China Sea,they can be deployed on a large scale within the block as well as other formations with similar high abrasion properties.