Abstract: Aiming at the common technical problems such as wellbore instability, slow drilling time, unqualified landing, low drilling encounter rate of coal seam, and resistance to casing running in three openings during the completion of the drilling of the 15# coal L-shaped horizontal well in the ZhengZhuang block of Qinshui Basin , through field engineering practice, taking Zhengzhuang block ZH-L49-1 as an example, adopting Key technical measures such as optimized wellbore trajectory design, optimizing drilling tool assembly, optimizing drilling fluid formula, precise landing control, geosteering, horizontal section well trajectory control, refined well-washing operations have effectively solved the technical problems of drilling and completion of the 15# coal L-shaped horizontal well in ZhengZhuang block. In the later stage, through field application, 9 L-shaped horizontal wells with 15 coal seams have been successfully completed, and the engineering quality is all qualified, which can provide reference for similar projects.