High-resolution sequence stratigraphic characteristcs and coal accumulation of Shitouhezi Formation in Hegang basin

Based on the principle of the high-resolution sequence stratigraphy, the base-level cycles of Shitouhezi Formation in Hegang basin were studied through the comprehensive analysis of the bore core and well logging data. As a result, one long cycle, five intermediate cycles and three different short cycles were recognized, and the high-resolution sequence stratigraphic framework was established. The research results also show that the accumulation of the coal in the study area was controlled by evolving of the base level cycles. The most favorable coal-accumulating epoch occurred in the late of the rising half long base level or the early of the falling half level. Giving the appropriate climate and terrain conditions, the thick coal could form around the stage of maximum flooding surface epoch. And during this epoch, the combination of the long rising half intermediate base level cycle and the short falling half intermediate base level cycle was favorable to depositing wide and thick coal seams. The study results have provided basis for broadening exploration of deep coal resources in Hegang basin.