Shale Oil Enrichment Mechanism of the Paleogene Xingouzui Formation, Jianghan Basin, China

Organic-rich lacustrine shales are widely developed in China, and they have long been simply regarded as homogeneous source rocks, which restricts the understanding of intrasource oil accumulation. At present, study LXF (Lower Member Xingouzui Formation) Jianghan Basin an unconventional reservoir is still its infancy, hydrocarbon accumulation mechanism unclear. Geochemical mineralogical studies were carried out on a suite samples from 100-m-thick sequence, i.e., II Oil Bed, by using XRD, SEM, MICP, Rock-Eval pyrolysis. The results show that Bed rich carbonate poor clay, so it shows good fracturing tendency. high degree heterogeneity mineral composition leads to frequent interbedding different lithofacies. In intercrystalline pores, interparticle intraparticle pores developed, micro-fractures often observed. However, main pore types, size distribution, connectivity quite among lithofacies, carbonate-rich lithofacies better capacity. OM (organic matter) abundance varies greatly generally ranges fair very good. Coupled with early-mature mature Type OM, considered characteristics required for generation. Comprehensive analysis has shale exploration prospects, enrichment sequence result multiple factors matching. Firstly, organic matter material basis enrichment. Secondly, thermal maturity prerequisite, difference burial depth differential areas. Thirdly, not only provide space storage, but also form flow-path network. Finally, multi-scale migrations key processes ranging scale intervals, further intervals. Considering generation capacity quality, prospective area >1350 m. findings this can help better-understanding mechanism, optimization future strategies.