The key geological parameters controlling the enrichment and productivity of shale oil and gas (O&G) are studied systematically using 991 shale core analyses, and assay data from 72 systematic coring wells and 1317 rigs from the lower section of the Eagle Ford Formation in the Gulf Coast Basin of the United States. The key parameters include both source and derived parameters. Source parameters are controlled mainly by the paleo-sedimentary environment, whereas derived parameters combine source parameters, thermal evolution, and tectonic evolution. Here we examine the evolution of, and relationships among, the source and derived parameters with respect to thermal and tectonic evolution. Derived parameters for shale, including total porosity (φt) and matrix permeability (Ke), are related to the source parameters of kerogen type, total organic carbon (TOC), clay volume content (Vclay), and effective shale thickness (Heshale), and can be represented by the source parameters and vitrinite reflectance (Ro), which directly reflects the thermal evolution of shale O&G. Shale O&G-derived parameters, including oil (So), gas (Sg), and water (Sw) saturation, are related to Ro, Vclay, and TOC, and can be represented by the source parameters and Ro. Shale O&G-derived parameters that control the “sweet spots” and enrichment of shale O&G include oil density (ρo), gas relative density (ρg), gas–oil ratio (GOR), water–gas ratio (WGS), oil volume coefficient (Boi), and gas compression factor (Z), and can be represented by Ro. Under the same conditions as the roof and floor in the effective shale layers, the formation pressure gradient (Pindex) can be represented by Ro, and shale compressibility can be represented by Vclay. Five parameters [TOC, Vclay, Heshale (effective shale thickness), Ro, and Pindex], combined with microfractures and sealing conditions, are the key parameters for assessing the enrichment, productivity, and “sweet spots” of shale O&G.