Study on the Temporal and Spatial Multiscale Coupling Flow of Shale Oil

Abstract

Shale oil is one of the world’s most important strategic energy reserves. The microscopic kerogen and matrix structure plays an important role in fluid flow and diffusion processes. The oil flow time in the shale reservoir is determined by the pore spatial scale. An accurate shale reservoir flow model must consider these factors. In this research, fluid flow, Fick’s diffusion in consideration of the time delay effect, desorption, as well as the absorption are considered using the molecular momentum correlation and the partial pressure law of the components. The effect of the above-mentioned factors on the time scale contribution of the well rate is discussed. The spatial distribution diagram of the time scale is constructed and analyzed. The results show that the production process is composed of five periods. The time delay effect is reflected by fluctuations in the production at periods 1–3. The time scale corresponds to different mediums. The oil mainly flows through the outer boundary of the stimulated region through surface diffusion. The time scale spatial distribution diagram also shows that the oil flows into the endpoint of the hydraulic fracture at an early stage. Moreover, the outer boundary needs a longer time to be exploited. The proposed model improves the simulation of shale oil flow, and therefore, would be favorable in designing a more suitable working system.