Abstract: To address the problem of low prediction accuracy of remaining oil in low-permeability reservoirs, taking Chang 7 tight reservoir in Yanchang Formation in the Ordos Basin as an example, the reservoir numerical simulation theory is applied, and the viscous motion equation is introduced to describe the direction and magnitude of pressure propagation in low permeability reservoirs. The results were applied to the study of remaining oil, and the potential tapping wells were optimally deployed in the remaining oil-enriched areas. The research result shows: With the extension of production time, the recovery factor will be underestimated without considering the viscosity, and the tracer tracing situation confirms the influence of viscosity on production; the numerical simulation results of low-permeability reservoirs considering viscosity have a good production history fit, with a single well fit rate of 89%; the numerical simulation results show that the remaining oil-enriched area is mainly located on both sides of the waterline, which is the area difficult to sweep between wells or the area with imperfect injection and production. The initial daily oil production of the potential tapping wells deployed in the remaining oil-enriched area is 12.8 t/d, which is nearly 4 times higher than that of the adjacent wells. The potential tapping wells deployed in the region are expected to increase the recoverable reserves by 9.27×10³t. The research results have reference significance for the potential tapping and later adjustment of remaining oil in similar reservoirs.

Key words: tight oil reservoir, proved reserves, remaining oil, dynamic analysis, development technology, Ordos Basin