浅水三角洲分流砂坝精细刻画新方法

综合应用岩心、测井、地震和示踪剂等动静态资料,根据构型层次分析理论,对渤海湾盆地A油田复合分流砂坝进行了精细表征,阐明了其内部空间结构。研究表明:地震振幅属性指示储层的横向变化,而振幅变化率能够更好地反映单砂体接触位置,根据边缘检测理论,将两者结合能够良好地识别单一分流砂坝侧向边界;同时根据低角度前积抽象理论模型可以定量刻画每一期分流砂坝顺源边界。研究区单一成因分流砂坝长600~1300 m,宽400~800 m,厚2.5~7.0 m;垂向上呈部分叠置、主体叠置和主体叠加3种接触样式,平面上呈孤立分布、边部侧向拼接和主体侧向拼接3种组合样式,总体呈"早期前积伴随侧向加积-晚期逐渐超覆加积"式演化。

New method for fine characterization of distributary bar in shallow water delta

Using core,logging,seismic and tracer data from A oilfield in Bohai Bay Basin,this article performed detailed characterization of distributary bar complex to illustrate its internal spatial structure based on the theory of reservoir architecture.The results show that amplitude attribute indicates the lateral variation of reservoir,while amplitude change rate better indicates the bounding surface of individual sand body.Based on the theory of edge detection,the combination of amplitude attribute and amplitude change rate can better identify the lateral boundary of single distributary bar.Eventually the boundary of single distributary bar along the source direction can be quantitatively identified by theoretical model of low-angle foresets.The length of single distributary bar varies from 600 to 1,300 m,with width from 400 to 800 m and thickness from 2.5 to 7.0 m.Vertically,multiple single distributary bars stacked with each other,presenting three contact patterns:partial superposition,superposition and overlay.While on the plane,multiple single distributary bars present three contact patterns:isolation,partial lateral splicing and lateral splicing.Generally,single distributary bars are characterized by progradation and lateral accretion in early phase followed by aggradation in terminal phase.