鱼卡煤田大煤沟组高分辨率层序地层特征及聚煤规律

HIGH RESOLUTION SEQUENCE STRATIGRAPHY OF THE DAMEIGOU FORMATION AND COAL ACCUMULATION IN THE YUKA COAL FIELD,QINGHAI

利用高分辨率层序地层学理论和技术方法,综合地震、测井、岩芯和煤质资料对柴达木盆地北缘鱼卡煤田中下侏罗统大煤沟组地层河湖三角洲沉积体系进行高分辨率层序地层学分析,从中识别出短期、中期、长期3个级别的基准面旋回层序,划分出向上"变深"非对称型、向上"变浅"非对称型及对称型3种短期基准面旋回基本结构类型。依据等时地层对比法则进行不同级次基准面旋回层序的联井对比,建立了大煤沟组的等时地层格架,在等时地层格架内进行了煤层对比,并在等时地层格架内分析了聚煤规律。

On the basis of integrated well data and seismic data,combined with the high resolution sequence stratigraphic data,the river-lake delta sedimentary system of the Dameigou Formation in the Yuka Coal Field in the north margin of the Qaidam Basin,was divided into short-term,middle-term and long-term base-level cycles.A short-term base-level cycle could be subdivided into asymmetric up-deepening,asymmetric up-shallowening and symmetric basic structure types.The base-level cycles of different orders are correlated in the restriction cycle isochrostratigraphy correlation.Isochronous stratigraphic frameworks are established and coal is correlated within them.Finally,the patterns of coal accumulation were analyzed within the isochronous stratigraphic frameworks.