摘要： 三角洲砂体是含油气盆地勘探的最主要储集体类型之一,湖相三角洲类型基本均为河控型三角洲。明确河控三角洲砂体发育机制、迁移规律、分布特征、组合结构等规律不仅具有科学意义,而且对于油气勘探具有重要的指导意义。影响河控三角洲砂体的因素较多,宏观上构造活动控制了盆地的类型、形成、演化、沉积底型形态、坡度及物源等。在构造相对稳定时期,河控三角洲砂体主要受3种因素控制: 物源供屑能力(简称物源),沉积底型坡度(简称坡度)和湖岸线位置(简称岸线)。物源供屑能力控制了砂体规模,体现在粒度、砂体厚度及范围;底型坡度控制了砂体宽厚比,表现在砂体前积层角度大小及三角洲形状;湖岸线河口处是沉积物主要卸载区,其位置及迁移幅度控制了砂体位置及连续性。3种因素不同的变化组合形成了不同特征的三角洲砂体分布模式。

关键词: 河控三角洲, 三元控砂模式, 物源供屑能力, 沉积底型坡度, 湖岸线迁移

Abstract: Delta sand body was one of the most important reservoir types for oil and gas exploration,and the lacustrine delta type was basically a river-dominated delta. To figure out the development mechanism,migration law,distribution characteristics and combination structure of sand body in river-dominated delta not only has scientific significance,but also has implications for oil and gas exploration. There are many factors affecting the river-dominated delta sand bodies. Tectonic activities control the type,formation and evolution of the basin,as well as the form of the sedimentary bottom type,the slope and the sediment source in a macroscale. In the relatively tectonic stable period,the sand body of a river-dominated delta was mainly controlled by three factors: The supply rate of the source(the source),the sedimentary bottom slope(slope)and the position of the lakeshore line(shoreline). The scale of the sand body was controlled by the supply capacity of the source,which was reflected in grain size,sand body thickness and distribution range;the sedimentary bottom slope controls the ratio of width to length,and was demonstrated by the angle of the front layer and the delta shape;The estuaries of the lakeshore were the main unloading areas of the sediments,and therefore,the position and the migration amplitude of the shoreline control the unloading position and continuity of the sand body. Different combinations of three factors lead to the different types and distribution pattern of delta sand bodies.

Key words: river-dominated delta, ternary sand control model, source power supply, sedimentary bottom slope, lakeshore line migration

中图分类号: 

• P531