Abstract: The precise prediction of formation drillability is of great importance to bit selection, ROP promotion and quick drilling. The formation of Yaojiapo and Heijiabao districts in Yanchang oilfiled is filled with hard and soft rock within each other, which leads to decreased ROP and poor drillability. In order to solve these problems, the logging data and well history are collected and a mathematical model correlating drillability and acoustic logging is established based on multiple rock drillability tests. Then the drillability distribution profile is got. The comparison between the prediction results and test results shows the error can be ignored. The research provides a scientific reference for bit selection and ROP promotion.