Abstract: To address the challenges of high drilling investment and difficulty in profitable development of shale oil reservoirs in Jiangsu Oilfield, this study takes the Yong 10A sidetrack well as the research object. On the basis of summarizing previous drilling experience, it validates and optimizes horizontal sidetracking techniques for old wells, and integrates a comprehensive technical system that includes deep open-hole window sidetracking, collaborative drilling with high-efficiency drill bits and non-stabilized screw, sweet spot tracking, diesel-based drilling fluid, and wellbore pressure control techniques for high total hydrocarbon values. Field application results show that the average rate of penetration (ROP) of Yong 10A sidetrack well reaches 15.98 m/h and the drilling cycle is 27.34 days, representing a 28% reduction compared to previous similar wells. Compared with the new drilling schemes, the investment was reduced by 12.3%. These findings effectively enhance the economic efficiency of shale oil drilling and provide crucial technical support for the economic development of shale oil in Jiangsu Oilfield.