Abstract: The Hadson thin reservoirs in Tarim Oilfield has great burial depth and large structural variations. The wellbore trajectories in horizontal wells are hard to control. The traditional rotary steering tools could not realize enough build-up rate at the early stage of sidetracking, so the bent screw motor was used first to build up hole angle to about 30°, then changed to other tools, which increased drilling risks and drilling cycle. In 2013, the rotary geo-steering tool with high build-up rate (PowerDriver Archer RSS) and a new generation of geo-steering technology (Scope series) were used in this Block, which started drilling with rotary steering from the sidetracking point, and geo-steering tools were added at landing and horizontal sections. Compared with 2012, the well depth in horizontal hole was increased by 214 m in average, and drilling cycle was less by 36.7 d. Based on rotary steering with high build-up rate and logging while drilling, and in conjunction with analysis of field application cases, it was thought that full-hole rotary steering helps reduce hole friction in Hadson reservoir and so save drilling time. The application of formation delineation drilling and reservoir evaluation techniques has improved the reservoir drilling ratio by horizontal wells, which helps large-scale production of this reservoir.