fax 01-972-952-9435. AbstractDrilling the 12 ¼" and 8 ½" sections in offshore Abu Dhabi's Deep Khuff fields is very challenging due to an intricate geological sequence that consists of limestone, dolomite and shales that are highly interbedded with hard stringers. Historically, ADMA-OPCO, the operator, has attempted to efficiently drill the section using roller cone tungsten carbide inserts (TCI), natural diamond and polycrystalline diamond compact (PDC) technology.PDC bits yielded better performance in terms of rate of penetration (ROP) and bit life over TCI bits. However, it required several PDC bits to drill the sections. Further detailed analysis produced optimum PDC designs that successfully established new benchmarks in the fields.