Abstract: Slim hole drilling technology has obvious cost advantage on the development of remaining oil and scattered marginal reservoirs but it has many technical difficulties, such as less bit option, high circulating pressure loss, insufficient rock-breaking ability and big control of wellbore trajectory. Therefore, based on the analysis of slim hole mechanical drilling rate, through optimizing bit, reducing the pressure loss, strengthening the drilling parameters and optimization of drilling assembly, a series of optimal and quick slim hole drilling technologies have been formed. The field application results show the optimal & quick slim hole drilling technology can effectively improve the drilling speed, reduce drilling cost and have a good applied foreground.