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为了厘清桑塔木地区三叠系砂体成因类型,指导油气勘探,利用岩心、钻测井、分析化验及高精度三维地震资料,研究碎屑岩的粒度、结构、沉积构造、砂体的空间展布、地震反射特征等.结果表明:三叠系TⅡ油组具有粒度细、分选磨圆好、发育小型交错层理、波状层理及水平层理,呈指状产出,地震剖面上具有前积反射构型,典型相干体地层切片见曲流特征的特点,是典型的曲流河三角洲沉积;同时,研究区曲流河三角洲发育2种亚相6种微相,其中平原亚相发育天然堤、水上分流河道及河漫沼泽微相,前缘亚相发育水下分流河道、河口坝和支流间湾3种微相;区内TⅡ油组以发育北部和西南部2个主要方向的曲流河三角洲为主,其中北部三角洲规模大,平原和前缘亚相较发育,西南部三角洲以前缘亚相为主,平原亚相以分流河道沉积为主,前缘亚相主要发育分流河道和河口坝微相.该三角洲的形成与地形坡度及气候的变化密切相关.
In order to clarify the genesis type of Triassic sandstone in Santamu, guide oil and gas exploration, use the core, drilling and logging, analytical laboratory and high-precision 3D seismic data to study the granularity, structure, sedimentary structure, sandbody space Distribution, seismic reflection characteristics, etc. The results show that the Triassic TⅡ oil group has fine grain size, good sorting and rounding, development of small cross bedding, wavy bedding and horizontal bedding, It is a typical meandering river delta deposit with the features of pre-sedimentary reflection and the formation of typical coherent body strata, meanwhile, there are 6 subfacies and 6 microfacies in meandering river delta of the study area, of which the plain subfacies There are three kinds of microfacies: natural dike, water distributary channel and river man swamp microfacies, leading edge subfacies developing underwater distributary channel, estuary dam and tributary bay. In the TⅡ oil group, there are two main directions of developing north and southwest Of the meandering river delta, of which the northern delta is large in scale, the plains and the frontier sub-relatively developed, the southwestern delta front mainly subfacies, the plain subfamily of distributary channel sedimentation, leading edge subfacies major development diversion River and estuary dam micro The formation of the delta is closely related to the gradient of the terrain and climate change.