A comprehensive mathematical model for spontaneous imbibition in oil-saturated fractured tight sandstones: Incorporating fracture distribution, displacement pressure, gravity, and buoyancy effects

This paper presents a generalized mathematical model that comprehensively characterizes the flow behavior of matrix nanopores and natural/hydraulic fractures in tight oil reservoirs during spontaneous imbibition. The incorporates various influencing factors such as fracture distribution, displacement pressure gradient, gravity, buoyancy. complex pore structure reservoirs, including natural microfractures, challenge developing an accurate for predicting behavior. proposed considers fractal characteristics pores accounts many to predict cumulative production, rate, recovery factor imbibition flow. Experimental data on fractured sandstones are used validate model, sensitivity analyses conducted assess influence parameters, fluid properties findings reveal gravity buoyancy effects become more prominent under low interfacial tension. Fracture distribution significantly impacts behavior, with critical values dimensions, numbers, apertures determining extent their influence. Higher contact angles increased phase viscosity result reduced efficiency. In pressure-driven processes, larger preferentially produce crude oil, higher gradients shorter processes. offers insights into mechanism can contribute improved factors.