抄録
Tight oil in continental saline lake basins is a key frontier in unconventional hydrocarbon exploration, featuring complex depositional settings and diverse accumulation mechanisms. This study reviews tight oil accumulation in the lower Xinguozui Formation, Qianjiang Sag, highlighting the critical control of salt rhythms. Integrating core analysis, pore structure characterization, well logging, and biomarker data, it reveals a source-reservoir integration model where reducing saline conditions enhances hydrocarbon generation, and late-stage salt mineral infill creates pore heterogeneity. Fourth-order salt rhythm cycles act as fundamental accumulation units, with spatial alternation between hydrocarbon generation during salinization and storage during freshening, aided by overpressure-driven near-source charging. Tight oil sweet spots align with salinization-freshening transition surfaces, showing regular cyclic distribution. The “salt rhythm” theory advances understanding of accumulation processes and guides precise exploration in similar basins.
