Search

Based on the comparison of basic geological conditions and enrichment characteristics of shale oil plays, the heterogeneity of source and reservoir conditions and differential enrichment of medium-high maturity continental shale oil plays in China have been confirmed. (1) Compared with the homogeneous geological settings and wide distribution of marine shale oil strata in North America, the continental medium and high maturity shale oil plays in China are significantly different in geological conditions generally; continental multi-cyclic tectonic evolution forms multiple types of lake basins in multi-stages, providing sites for large-scale development of continental shale oil, and giving rise to large scale high-quality source rocks, multiple types of reservoirs, and diverse source-reservoir combinations with significant heterogeneity. (2) The differences in sedimentary water environments lead to the heterogeneity in lithology, lithofacies, and organic material types of source rocks; the differences in material source supply and sedimentary facies belt result in reservoirs of different lithologies, including argillaceous and transition rocks, and tight siltstone, and complex source-reservoir combination types. (3) The heterogeneity of the source rock controls the differentiation of hydrocarbon generation and expulsion, the diverse reservoir types make reservoir performance different and the source-reservoir configurations complex, and these two factors ultimately make the shale oil enrichment patterns different. Among them, the hydrocarbon generation and expulsion capacity of high-quality source rocks affect the degree of shale oil enrichment. Freshwater hydrocarbon source rocks with TOC larger than 2.5% and saline hydrocarbon source rocks with TOC of 2% to 10% have a high content of retained hydrocarbons and are favorable. (4) High-abundance organic shale is the basis for the enrichment of shale oil inside the source. In addition to being retained in shale, liquid hydrocarbons migrate along laminae, diagenetic fractures, and thin sandy layers, and then accumulate in laminae of argillaceous siltstone, siltstone, and argillaceous dolomite, and dolomitic siltstone suites, etc. with low organic matter abundance in the shale strata, resulting in differences in enrichment pattern.

The effect of cold plasma treatment on the microbial community of air at the 0 ℃ cold storage was studied. The structure and diversity of the bacterial and fungal communities were analyzed by high-throughput sequencing technology. The microbial symbiosis network was constructed. The results showed that the total concentration of bacteria and fungi decreased from 480 CFU/m3 to 44 CFU/m3 after cold plasma cyclic treatment for 30 days. The α diversity of bacterial and fungal communities was also significantly reduced. Principal co-ordinates analysis and permutational multivariate analysis of variance showed that the bacterial community and fungal community were significantly different before and after the treatment. Before cold plasma treatment, Bacillus, Comamonas and Acetobacter were the dominant bacteria of the cold storage air, while Saccharomycopsis, Aspergillus, Thermoascus, Rasamsonia, Penicillium, Wickerhamomyces and Russula were the dominant fungi. After cold plasma treatment, Acetobacter and these dominant fungi were significantly reduced. The symbiotic network analysis showed that there was a strong positive correlation between Sedimentibacter and other bacterial species. Besides, Saccharomycopsis, Thermoascus, Rasamsonia and Wickerhamomyces were the key nodes in the fungal symbiosis network and positively correlated with each other. This work indicates that cold plasma can significantly reduce the microbial quantity and diversity of microbial community in the cold storage, and can effectively kill some phytopathogen and pathomycete, which has a good application prospect in the cold storage of fruits and vegetables.