The Study On The Sedimentary Environment And Coal-accumulating Regularity Of San Bei Yang Chang

The Ordos basin is rich in coal resources. In recent years, fruitful results ofexploration were achieved, such as Zhuozishan coal field. These results provided detailedtheoretical basis for the exploration of the basin, but some areas inside the basin still needfurther geological work. In this paper, Sanbeiyangchang coal bearing area which is inZhuozishan coal field was chosen as the research object. Through collecting drilling datagained in reconnaissance stage, taking advantage of previous results of exploration andstudy, and using theories on sedimentology, sedimentary facies and environment and coalaccumulation mode in Sanbeiyangchang were discussed. The results were as follows:1. The main sedimentary environment in Sanbeiyangchang area was marine-continentalalternating delta and inland lake delta.2. Coal seam16in Taiyuan group was widely and steadily distributed in study area. Andthere was a thick coal accumulation area for it. This area showed a negativerelationship with the thickness of sandstone. Thick coal seams were distributed in deltaplain, and thin seams were in lagoon.3. Coal seam12in Shanxi group was thin throughout the study area. Combined withsingle-hole lithological association, this might be caused by the transformation ofsedimentary system. Coal seam9was widely distributed in the study area, and itsfavorable accumulation environment was peat swamp in delta plain. Coal seamthickness showed a positive relationship with sandstone and mudstone. Besides, coalseams had obvious zoning character, and thin seams were distributed in the south ofthe study area.4. By comparing the study area with the Ordos basin and Shanxi area on coalaccumulation sedimentary environment and stratigraphic horizon, coal seams’ richstrata were the same in these areas. The main coal accumulation environment wasdelta plain. And partially sedimentary environments differed slightly.