The drilling geological environment of Kozasay Oilfield in Kazakhstan is complicated， where the reservoir is located under the salt， multiple formation groups are to be drilled and the stratigraphic properties vary greatly， and there are multiple pressure systems. As a result， complex conditions such as formation leakage， collapse， block loss， creeping of the salt paste layer occurred during the drilling process， which seriously affected drilling efficiency and drilling safety. In response to the above technical problems， analysis and optimization have been carried out on well structure， well quality， speed-up potential， and high-efficiency drill bits with presentation of the pre-bent drill tool high-dip formation well deviation control technology， hybrid bit vibration reduction and speed-up technology， and PDC-impregnated block hybrid drill bit high abrasive formation speed-up technology. The field application has achieved good results with average ROP increased by more than 50%， and the drilling duration shortened by 28%.