The drilling geological guidance technology has been widely used in the process of horizontal well construction. In the process of continuous development of new technologies such as reservoir mapping-while-drilling, the application of density imaging technology in the drilling geological guidance technology is still relatively common. In view of the problems of low well control, large structural changes, and rapid lateral changes of reservoirs in the Z oilfield in the western South China Sea, density imaging tools and corresponding geosteering techniques were introduced. With the help of high-resolution density imaging results, the precise formation dip was picked up, and on this basis, the structural shape was analyzed and confirmed, and the relative position of the trajectory was judged. The lithology conditions were determined on the basis of geological logging to avoid layer breakout caused by local phase transformation, thus providing judgment basis for real-time decision-making and guiding geosteering. During the implementation process,the concept of the apparent dip angle through the well axis was proposed and used for the first time, and the conventional method of calculating the formation dip angle by using imaging data has been improved and verified by actual comparison. At present, 4 horizontal wells have been drilled in this block, with an average length of 580 m,and the drilling encounter rate of high-quality reservoirs is 80%. It is concluded that using this technology in the structure with obvious density changes and lithologic reservoirs can effectively reduce geological risks such as structural uncertainty and improve the drilling rate of high-quality reservoirs.