准噶尔盆地南缘四棵树地区中浅层砾岩层识别刻画

准噶尔盆地南缘中、下组合构造普遍位于中浅层砾岩层之下,砾岩层具有横向展布范围广且不规则、纵横向速度变化大等特点,严重制约中、下组合目标的精细落实。因此,搞清砾岩层结构及分布特征,对下伏构造形态和高点位置的准确落实尤为重要。结合微测井、钻井、测井资料以及地震剖面对准噶尔盆地南缘四棵树地区中浅层砾岩层结构特征进行分析,对低速和高速砾岩层的顶底界面进行识别刻画,并分区、分段建立了砾岩层时深关系曲线,用于指导深度域下组合构造成图和叠前深度偏移中浅层速度模型的建立。实例应用证明,南缘四棵树地区中浅层砾岩层识别刻画对准确落实构造目标,提高地震剖面成像品质至关重要,同样也可以在准噶尔盆地南缘其他类似地区进行推广应用。

Identification and Characterization of Middle-Shallow Conglomerates of Sikeshu Area in the Southern Margin of Junggar Basin

The middle-lower assemblage structure in the southern margin of Junggar basin is generally located below the middle-shallow gravel belt,and the conglomerates are characterized by wide and irregular lateral distribution and large variations of vertical velocity,which seriously restrict the fine identification of the targets in the middle-lower assemblage.Therefore,it is very important to figure out the struc⁃ture and distribution of the gravel belt for accurately identifying the configuration and high point position of the underlying structure.Com⁃bining micro⁃logging and drilling data with seismic sections,the paper analyzes the structural characteristics of middlle-shallow conglomer⁃ates,describes the top and bottom interfaces of low⁃speed and high⁃speed conglomerate intervals of the Sikeshu area in the southern mar⁃gin of Junggar basin,and establishes time⁃depth curves by districts and sections,which can be used to guide the accurate depth⁃domain mapping of composite structures and the velocity model building of the middle and shallow layers for prestack depth migration.The applica⁃tion result shows that the identification and characterization of the middle-shallow conglomerate of the Sikeshu area in the southern margin of Junggar basin is of great help for the accurate determination of the structural objectives and the imaging quality improvement of the seis⁃mic sections,which can also be applied in other similar areas in the southern margin of Junggar basin.