An operator drilling in west Kazakhstan needed to achieve a quality borehole to set a 7-in casing through loosely consolidated limestone with unconfined compressive strength (UCS) of 20,000 psi. Using offset well data, surface and downhole measurements, and a thorough knowledge of products and applications, the i-DRILL system design process created a virtual drilling environment in the sensitive limestone formation. Detailed geometric input parameters and rock mechanics data were taken into account in simulating the drilling environment. The i-DRILL system design simulations helped determine the best combination of speed and WOB to achieve maximum ROP with optimal reaming parameters. The system design analyses helped evaluate dynamic behavior and identify issues with vibration, bending moments, and torque.