Tight oil has broad prospects for exploration around the world. There have been achieved success exploration and development of tight oil reservoirs in some foreign basins. China has a large area of unconventional oil and gas resources, of which coalbed methane and shale gas have been well studied, but tight oil is still in its infancy, and its evaluation basis is still weak. By analyzing the control factors of tight oil accumulation, the accumulation process and the accumulation dynamiction, it is believed that the basic theoretical work of tight oil accumulation should be carried out as soon as possible. Especially, there is an urgent need for breakthroughs in the study of the time relationship between tight oil accumulation and reservoir densification and formation mechanism of tight oil reservoir-forming dynamiction.

Uranium mineralization in the Zhiluo Formation of the Saitai area preferentially occurs in carbonaceous debris- and pyrite-rich sandstones. This study characterizes ore fluid and reducing medium controls on uranium enrichment and uranium mineral genesis using core observations, SEM, EPMA, and geochemical tests. Uranium minerals mainly form zoned aggregates around carbonaceous debris, occur with colloform pyrite within feldspar and carbonate dissolution pores, and appear within zones of biotite breakdown. Whole-rock geochemical data from ore-bearing sandstone show variations: U(IV)/U(VI) (0.625–34.78; corresponding to U(IV)/total U of 0.38–0.97), Ce/Ce* (0.72–1.01), Fe²⁺/Fe³⁺ (0.70–92.35; Fe²⁺/total Fe of 0.41–0.99), TOC (0.026–3.35%), total sulfur (0.1–0.3%), and S²⁻ (3.4 × 10⁻⁶–83.3 × 10⁻⁶). Fluid inclusions in calcite cements show homogenization temperatures of 130–183 °C, and those hosted in intergranular calcite cluster at 130–138 °C, with salinities of 0.9–9.5 wt.% NaCl equivalent and CO₂-bearing characteristics. Mineralization of the Zhiluo Formation developed in a medium–low temperature, reducing alkaline environment. Carbonaceous debris shows close spatial and genetic links with uranium minerals. Authigenic pyrite correlates with uranium through paragenetic association with carbonaceous fragments. Alkaline fluid dissolution provides pore space for uranium and secondary pyrite precipitation.