Application of coal facies parameters in sequence stratigraphic division of coal seams: with Zhangnanxi coal district, Junggar basin as example

On the basis of the principles and approaches of sequence stratigraphy, using drilling and logging data, maceral and coal facies parameters of coal seam, this study divided the sequence units of Xishanyao Formation in Zhundong coal field, especially the parasequences in coal seams. The results showed that Xishanyao Formation belongs to one third-order sequence and consists of low-stand system tract, transgression system tract, high-stand system tract; the transgression parasequence and regression parasequence, and transgression parasequence set and regression parasequence set in coal seams are distinguished; The thick coal seam in transgression system tract consists of the transgression parasequence and regression parasequence, and the thick coal seam in high-stand system tract consists of the regression parasequence; The coal facies belong to dry forest swamp.