辽宁阜新盆地下白垩统沙海组沉积环境与聚煤规律

Sedimentary environments and coal accumulation patterns of the Lower Cretaceous Shahai Formation in Fuxin Basin,Liaoning Province

阜新盆地下白垩统沙海组沉积环境和聚煤规律研究较为薄弱。在野外观察的基础上,结合岩心观察与描述、连井剖面分析以及测井曲线分析等手段,对阜新盆地沙海组沉积环境和聚煤规律进行分析。结果表明:阜新盆地沙海组主要可识别出冲积扇—扇三角洲沉积体系和湖泊沉积体系;沙海组可分为3个三级层序,每个层序又可进一步分为湖侵体系域和高位体系域,其中沙海组一段和二段为Sq1,沙海组三段为Sq2,沙海组四段为Sq3;沙海组煤层主要分布在Sq2中。Sq2湖侵体系域的聚煤中心为清河门镇至伊玛图乡、东梁镇南和九道岭镇,Sq2高位体系域的聚煤中心为清河门镇和九道岭镇;沙海组成煤的沉积模式为湖侵体系域扇间洼地沼泽化成煤和高位体系域扇三角洲前缘成煤。其中湖侵体系域扇间洼地沼泽化成煤模式要好于扇三角洲前缘成煤模式。

The research on sedimentary environment and coal accumulation pattern of the Lower Cretaceous Shahai Formation in Fuxin Basin is relatively insufficient.Based on field observation and combines the observation and description of borehole cores and outcrop sections,across well profile analysis and well logging curves,the authors analyzed the sedimentary environments and coal accumulation pattern of the Shahai Formation in Fuxin Basin.The result shows that alluvial fan-fan delta sedimentary systems and lacustrine sedimentary system were developed in the Shahai Formation of the Fuxin Basin.The Shahai Formation can be divided into 3 third-order sequences and each sequence can be further subdivided into transgressive systems tract and highstand systems tract.Among them,the Members 1 and 2 of the Shahai Formation belong to Sq1,the Member 3 of Shahai Formation belongs to Sq2 and the Member 4 of the Shahai Formation belongs to Sq3.Coal seams of the Shahai Formation are mainly distributed in Sq2.Coal accumulation centers of transgressive systems tract of Sq2 are distributed in the Qinghemen-Yimatu County,South Dongliang County and Jiudaoling County,while those of highstand systems tract in Sq2 are located in the Qinghemen County and Jiudaoling County.Depositional models of coal formation in the Shahai Formation include inter-fan paludification coal formation in the transgressive systems tract and deltafront coal formation in highstand systems tract,among which the former is better than the latter.