Fracturing fluid–rock interaction and pore structure evolution in shale oil reservoirs.

This article focuses on the quantitative evaluation of pore structure evolution in shale oil reservoirs induced by interactions with hydraulic fracturing fluids. Using a combination of advanced analytical techniques—including X-ray diffraction, multidimensional electron microscopy, micro-computed tomography, gas adsorption, and mercury intrusion—the study reveals that fracturing fluids cause mineralogical changes (notably a decrease in carbonate minerals and an increase in clay minerals) and complex modifications to pore morphology. While fracturing fluids promote the development of dissolution pores and microfractures, they also induce mineral detachment and pore blockage, leading to an overall reduction in pore volume (29.6%) and specific surface area (46.8%), especially in micropores and mesopores. These findings provide critical insights into the multi-scale pore structure alterations affecting reservoir quality and fluid flow, with implications for optimizing hydraulic fracturing and related processes such as CO2-driven oil recovery and geological sequestration.