西湖凹陷花港组层序地层划分和聚煤特征

为了揭示西湖凹陷花港组的聚煤特征及煤层在层序内部的发育位置和分布，在对西湖凹陷地震、钻测井及岩芯资料综合分析的基础上，运用层序地层学、沉积学及煤地质学的有关理论和方法，识别出两个长期基准面旋回和7个中期基准面旋回，且花港组发育煤层的主要沉积环境有河流、湖泊三角洲、辫状河三角洲及湖泊，其中长期基准面旋回LSC4中发育煤层的主要沉积环境有河流、湖泊三角洲及辫状河三角洲，长期基准面旋回LSC5中发育煤层的沉积环境主要为湖泊。在长期基准面旋回LSC4中煤层主要发育于中期基准面旋回的最大可容纳空间处，长期基准面旋回LSC5中煤层主要发育于该旋回的上升半旋回中，并且这两个长期基准面旋回中发育的煤层在平面分布特征上表现为东厚西薄。可容纳空间的大小控制着花港组煤层的发育，在长期基准面旋回最大可容纳空间附近形成的煤层在全区均有分布，而在中期基准面旋回最大可容纳空间附近形成的煤层分布范围较小。

Sequence stratigraphic division and concentrating coal characteristics of Huagang Formation in Xihu depression

For unveiling coal accumulation characteristics,coal seam development location and distribution in sequence of Huagang Formation in Xihu depression,on the basis of comprehensive analysis to seismic,drilling,logging and core data,after application of relevant theory and means of sequence stratigraphy,sedimentology and coal geology,two long-term base level cycles and seven mid-term base level cycles were recognized and the main sedimentary environment developing coal seam were fluvial,lake delta,braided river delta and lake in Huafang Formation;and the main sedimentary environment developing coal seam in long-term base level cycle 4 were fluvial,lake delta and braided river delta,the main sedimentary environment developing coal seam in long-term base level cycle 5 were lake.Coal seams mainly developed in the maximum accommodation of mid-term base level cycles in long-term base level cycle 4,and coal seams mainly developed in increasing long-term base level cycle 5,and the plane distribution characteristics of coal seams in long-term base level cycle 4 and long-term base level cycle 5 are thick in east and thin in west.The developing coal seams in Huagang Formation are controlled by the size of accommodation,coal seams developing near the maximum accommodation of long-term base level cycle are distributing in the whole section,but the distributing area of coal seams developing near the maximum accommodation of mid-term base level cycle are less.