Abstract: The subject of this study was shale gas of the Cambrian Qiongzhusi Group located in the Weiyuan County of southern Sichuan. First, the reservoir evaluation results from adjacent logging wells were used to select the "geological sweet spot" as the geosteering target layer; next, we analyzed the LWD (Logging while drilling) response characteristics, such as varying lithology, physical properties, lubricity, and brittleness, of stratigraphic cross sections encountered along the well hole trajectory. Based on the LWD and MWD (Measuring while drilling) data, we determined the stratum's dip angle and thickness in real time and accurately established a preliminary geological and physical model. Finally, using well hole trajectory-LWD curve-reservoir lithology cross-section integrated mapping technology, we promptly identified the location, extension length, and incline/decline direction of the horizontal well hole trajectory within the shale reservoir and optimized the well hole trajectory in real time and revised the preliminary geological and physical model to guide the drilling bit to a high-quality shale reservoir, thus improving the reservoir encounter rate. Applying this method to geologically guided drilling of horizontal shale gas wells within the study area led to significant results.

Key words: shale gas, horizontal well, well hole trajectory, preliminary geological and physical model, LWD