Nanopore Size Distribution Heterogeneity of Organic-Rich Shale Reservoirs Using Multifractal Analysis and Its Influence on Porosity–Permeability Variation

The shale nanopore size (diameter <100 nm) distribution heterogeneity (SNDH) is one of the important factors affecting gas production. However, quantitative analysis SNDH and applicability single multifractal models need to be further studied. Here, based on low-temperature liquid nitrogen carbon dioxide tests organic-rich in Qinshui Basin, dimension variation micropores (<2 mesopores (2–100 are studied, that affect nanopores determined. Additionally, differences between fractal results compared. Based this, dynamic porosity permeability under constraints structure discussed from perspective variation. this study as follows: (1) pore meso–macropores samples exhibit typical behavior. overall mainly affected by pores low-value area volume (LAPV), while high-value volume. parameters influencing clearly different. (2) D2 calculated using Frenkel–Halsey–Hill model has a negative correlation with parameters, implying LAPV gradually decreases increase value, indicating physical meaning two obviously (3) affects diffusion process reservoir. With meso–macropores, damaging effect stress stronger. more heterogeneous micropore distribution, smaller ?modification effect? coefficient.