Late Paleozoic Sedimentary Characteristics And Coal-bed Gas Influence Of Source Rock In Sanxi Baie

The study area is located in south Hedong coalfield in north China accumulation coal depression, a weak local structural deformation, the basic structural form for the trend NE-NNE, tend to NW monocline structure, formation dip generally 3 ~ 8°. Stratigraphic development of the region is complete, sedimentation stability. Late Paleozoic Permo-Carboniferous coal-bearing rocks is full of coal . It is China's major coal-bed zone.By drilling cores, logging curve, particle size analysis and microscopic identification , using sequence stratigraphy of the basic principles and research methods, according to deposition of base-level variation, and combined with the research results of other parts of North China basin, we set up the sequence stratigraphic framework of the Late Paleozoic Permo-Carboniferous coal bearing formation.It is divided into three super-sequences, nine three sequences.The changes of accommodation space is because of the lift and down of the deposition of base-level space .Not only form a clear cyclostratigraphy ,but also made coal accumulation in a significant stage. In the study area, Carboniferous-Permian coal-bearing rocks filling sequence, due to the combined effect of construction, material source of supply and climate, the Carboniferous Benxi, Taiyuan tidal flat depositional system development. 7 #, 10 #, 12 # coal seam is mainly tidal flat peat swamp formed. Shallow-water delta is formed in the Permian Shanxi. It forms in the basin flat slope, water more shallow and stable,so generally well-developed delta plain and a larger scale. Distributary interchannel depression of the shallow-water delta form the peat swamp. In the peat swam form a larger thickness ,the distribution of stability, with the value of industrial exploitation 2 #, 3 # coal seam. Middle and Late Permian is the continental river and lake deposits, due to dry climate and forming gray, offwhite, purple and other variegated clastic rocks. The lifting of the Late Paleozoic base-level cycles can form coal seam (or coal line), but the extent of development of coal accumulation and distribution varied widely. with industrial significance of the main coal seam formed in the up half-cycle of ultra-long-period in the super sequenceⅠ.That is, the continuous deposition of base-level elevation and the persistence of accommodation space as a guarantee .The accommodation space of coal swamps of the accommodation space is increasing, and water table rise, stability sedimentation become stronger. Because the supply of weakening, combined with the climate, tidal flat become peat swamp, Sq2, Sq3 and Sq4 the transgresss systems tract of sequence to form the general development of the region's coal seam in the super-sequenceⅠ.Because the coal seam form in different sedimentary environments , coal quality is different .thus affecting the amount of coal seam bed is made. through coal quality analysis of the 2 #,3 # and 10 # coal seam and cbm analysis experiments ,showing Vitrinite Amount of 10# coal seam which formed in tidal flat higher than 2 #, 3 # coal seam which formed in peat swamp .10 # coal seam of making cbm capacity is higher than 2 #, 3 # coal seam.