This study reveals hydrocarbon charging enhances reservoir quality in tight sandstones, suggesting better exploration strategies for lower permeability sites.
Hydrocarbon charging critically controls diagenesis and reservoir quality in tight sandstones. This study employs thin section petrography, fluid inclusion analysis, stable isotopes, and production data to investigate the Yanchang Formation in the Ordos Basin. The results show that late carbonate cement (CcII) was related to decarboxylation of organic matter, and its formation stage is consistent with the hydrocarbon expulsion stage of source rock. Early hydrocarbon charging suppressed late‐stage cementation while exerting dual reservoir effects: (1) High oil‐bearing zones exhibit enhanced porosity and permeability with reduced carbonate content; (2) Early charged reservoirs develop pore‐occluding bitumen, degrading connectivity. Wettability shifts to oil‐wet states promoted high‐maturity oil migration through microfractures. The integrated framework highlights the necessity of coupling charge history with diagenetic pathways to optimise exploration in low‐permeability reservoirs.
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Wang et al. (2025) studied this question.
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