Study on development features and coal accumulation of coal bearing strata in Shiwan Mountain Foreland Basin of Guangxi

Based on a close relationship existed between sedimentary environment and coal accumulation law of coal bearing strata in Shewan Mountain Foreland Basin, in order to have coal accumulation law in the region, in combination with the site measurement on the field strata cross section, geophysical logging, well connec ted cross section analysis and other means, the modern sedimentology and the theory and method of the high resolution sequence strata analysis were applied to analy ze the petrology features, sedimentary environment, base level cycle type and coal accumulation law. Three sedimentary facies types of the fluvial facies, river delta fac ies and lake facies were indentified. The study showed that the main development of the coal accumulation role was the marsh environment on the floodplain and the s hort-term base level rising of the asymmetry cycle later period. The basin could hold a high space and high supply quantity and would have a fast sedimentary speed. T he seam thickness was 0.2 ~ 1. 0 m with a poor continuity and unstable thickness.