The sedimentary setting and the source rock of Longtan(Wujiaping) strata in the northeastern Sichuan Basin

Guided by the depositional models of marine carbonate rocks, the sedimentary facies of the Late Permian Longtan strata in the Xuanhan-Daxian region is interpreted on the basis of sedimentary facies of single wells, drilling as well as surface outcropping data. The sedimentary facies in the region is typical gen-tle slope stagnant sea which produced large scale black mudstone and dark limestone. Through geochemistry analysis, it is confirmed that this source rock is a type of the important source rocks in northeastern Sichuan. The kerogen of this source rock is very good. This source rock contains a great deal of organic matters. The content of TOC varies from 0.5% to 27.1%, the average TOC is 2.91%, and most Of them are 3%-5%.