【摘要】 分析了海拉尔河牙克石段的沉积演化特征,从沉积机制上对曲流河废弃河道进行了详细地解剖.河流截弯取直后,主流河道内不同水位与取直坝高度两者间的相互关系决定了废弃河道与主流河道的连通状态、废弃河道接收沉积物质的粒度变化.废弃河道沉积与周围点坝砂体间的岩性、物性差异使其在平面上形成连续封闭的围墙式的遮挡条带,分隔曲流带砂体形成点坝为单元的砂体组合.废弃河道的平面展布发育有2大类4小类型:串沟型、颈切型、决口改道型、串流改道型.在沉积认识的指导下,完成密井网条件下对地下废弃河道的测井、地震识别,并实例刻画了废弃河道的形态,分析了其遮挡效应.更多还原

【Abstract】 Based on the analysis of the sedimentary evolution characteristics of Yakeshi segment of Hailaer river,the sedimentation mechanism of the abandoned channel is analyzed in detailed.It is shown that,after the curved segment of the channel is cutoff and the channel becomes more direct,the relative height between the water level in active channel and the bar of the direct segment determines the connection state between the abandoned segment of the river and the active channel and the variation of the grain size of the deposition in abandoned channel.The difference of the lithology and the physical property between the abandoned channel and its surrounding sandbodies leads to the formation of a continuous closed wall-like barrier belt.The meander belt sandbody can be divided into a set of point bars by the barrier-belt.According to the processes of natural cutoff,the abandoned channel is classified four types:chute cutoff,neck cutoff,crevasse cutoff and cross cutoff.Based on the fluvial sedimentology,the abandoned channel is identified from the logging curve and the seismic section under the condition of dense well pattern.The GH2 well area in Gangdong Oilfield is taken as an example,and the platform and shielding effect of abandoned channel is described.更多还原