准噶尔盆地东北缘侏罗系含煤岩系层序地层和隐蔽圈闭

准噶尔盆地东北缘侏罗系沉积时期,存在地形坡折带。根据不整合面、稳定分布的厚煤层等标志将侏罗系中下统划分成 4个沉积层序。以地层叠置样式、局部分布的煤层以及地形坡折带在沉积层序中的位置,细分出低位、湖侵和高位体系域。低位体系域以深切谷(辫状河)沉积为特征;湖侵体系域以广泛分布的湖相沉积为特征;高位体系域发育进积式三角洲。在建立具地形坡折带的陆相湖盆含煤岩系层序地层模式和分析成藏条件的基础上,预测低位体系域深切谷和高位体系域三角洲前缘远端透镜状砂体是隐蔽圈闭发育的地区。

SEQUENCE STRATIGRAPHY OF JURRASIC COAL-BEARING MEASURE AND SUBTLE TRAP IN THE NORTHEAST EDGE OF JUNGGAR BASIN

There was a topographic break in the northeast edge of Junggar basin during Jurassic Period.Middle-Lower parts of Jurassic can be divided into 4 sequences according to sequence boundaries,such as unconformity and thick coal bed.Lowstand system tract,lacustrine transgression and highstand system tracts in the interest area can be subdivided by the repeated pattern of stratigraphy,locally distribution of coal-bearing measure and the location of topographic break in sedimentary sequence.Lowstand system tract is characterized by the incised valley (braided river) sediment,lacustrine transgression system tract is represented in nature by the widespread of lacustrine sediment and highstand system tract is featured by the prograding delta.It is predicated that,on the basis of establishing a model of sequence stratigraphy of coal-bearing measure in lacustrine basin with a topographic break belt and analyzing the conditions of hydrocarbon accumulation,the incised valley in Lowstand system tract and distant lenticular sandbody in front of the delta in highstand system tract is the area where subtle trap formed.