The development of horizontal well can improve the productivity of single well and the overall development benefit,but the premise is that the horizontal well has a higher drilling rate. Higher drilling rate is relatively easy for the development of horizontal wells in conventional reservoir,which has inherent advantage,but it is difficult for the reservoir with strong heterogeneity,such as the Chang 8 reservoir of ML Oilfield. At the same time, site tracking while drilling is also very tricky. According to the literature research, the main layer selection of horizontal well development is mostly qualitative method, and the quantitative method is less.From the resistivity and acoustic time difference of the main logging parameters that affect the heterogeneity of the reservoir,and combined with the actual needs of horizontal well trajectory design,this paper presents a fine optimization technique of the longitudinal main production layer in a small scale. Since 2015, in the ML oil field ,the practice application effect is ideal, because of the horizontal well design in large-scale application of quantitative main production layer optimization technology, and the application of 3D geological modeling while drilling and RDMS horizontal well drilling technology of remote monitoring and control system in horizontal section trajectory adjustment.