和什托洛盖盆地中侏罗统西山窑组层序地层及聚煤规律分析

Sequence Stratigraphic Analysis and Coal Accumulation of the Middle Jurassic Xishanyao Formation in the Heshituoluogai Basin

和什托洛盖盆地中侏罗统西山窑组发育多套煤层。据钻井岩心和测井曲线资料,研究和什托洛盖盆地中侏罗统西山窑组层序地层格架及沉积体系空间展布特征,在此基础上分析煤的聚集规律。研究区主要发育辫状河、三角洲和湖泊3种沉积体系,物源来自盆地南北方向。西山窑组可划分为两个三级层序,煤层主要分布于三级层序的湖扩和高位体系域,高位体系域中晚期为泥炭沼泽发育的最佳时期。

Large amounts of coal emerged in the middle Jurassic Xishanyao formation of Heshituoluogai basin.Along with the drilling borehole and well log,the sequence stratigraphic frame of Middle Jurassic Xishanyao formation in Hes- hituoluogai basin is established.The space distribution of the sedimentary system and the coal accumulation are discussed.It can be concluded that the study area mainly are deposited in three types of depositional systems：braided river, delta and lake.The sediment source of basin comes from its north and south.It can be also concluded that Xishanyao formation is divided into two third-order sequences,and expansive system tract and high-stand system tract are conducive to grow coals,and the middle-late of high-stand system tract is the most advantageous stratum for coal accumulation.