Determining the lower limits of pore and throat sizes for shale oil occurrence is essential for reservoir evaluation, yet existing methods yield a single fixed threshold that fails to capture the heterogeneity of interbedded systems. This study addresses this limitation through integrated characterization of 59 core samples from the Chang 7 Member, Longdong area, Ordos Basin, using high-pressure mercury injection (HPMI), low-temperature nitrogen adsorption (LTNA), nuclear magnetic resonance (NMR