西湖凹陷古近系平湖组聚煤环境特征及模式

The coal-accumulating environments characteristics and coal-forming pattern of Pinghu Formation(Paleogene) in Xihu Depression

利用钻井、岩心等资料,对西湖凹陷古近系平湖组聚煤环境及模式进行研究。西湖凹陷平湖组的主要聚煤环境为潮坪相潮上-潮间泥炭沼泽、潮控三角洲平原泥炭沼泽以及辫状河三角洲平原泥炭沼泽。综合聚煤环境和古构造因素的影响,建立平湖组沉积期的潮坪-三角洲聚煤模式,研究区潮坪和潮控三角洲较辫状河三角洲更有利于聚煤;平湖组下段至上段煤层平面上分布范围逐渐扩大;西部斜坡带聚煤作用强于东部断阶带。

Coal-accumulating environments characteristics and coal-forming model of Pinghu Formation（ Paleogene） in Xihu Depression have been studied using the drilling data and core data in this paper. The coal seams of the Pinghu Formation in Xihu Depression were formed in peat swamps of supratidal zone and intertidal zone of tidal flat facies,peat swamps of the tide-dominated delta plain and the braided river delta plain. Considering the coal-accumulating environments and the paleostructure effects,the tidal flat-delta coal-accumulating model for Xihu Depression of Pinghu Formation is established. The coal accumulation in the tidal flat and the tide-dominated delta are better than in the braided river delta. The distribution of coal-forming sedimentary system is gradually spread from the lower member to the upper member of the Pinghu Formation. The west slope of the depression has a stronger coal accumulation effects than the east fault-terrace belts of the depression.