构造断阶与砂体预测:以沾化凹陷富林地区为例

STRUCTURAL FAULT TERRACE AND SAND BODY PREDICTION:AN EXAMPLE FROM FULIN AREA,ZHANHUA SAG

程日辉 郑和荣 林畅松

Cheng Rihui Zheng Herong Lin Changsong

构造断阶带包括陡坡和缓坡断阶带。因地形差异,陡坡和缓坡对砂体的控制作用存在明显不同。低水位期,陡坡一侧发育冲积扇、扇三角洲;缓坡一侧发育河流冲积平原、小型冲积扇或三角洲。湖进期,陡坡一侧由岸向湖,不同断阶上分别发育冲积扇或扇三角洲的近 中端,中 远端,在靠近深洼部位发育湖底浊积扇或其它重力流沉积体;缓坡一侧,则表现为前期沉积的砂体向物源方向的退积。高水位期,因地形变缓断阶作用变小,整体表现为三角洲向盆地的进积,呈延长楔形或透镜状。另外,断阶中断裂活动的先后次序和迁移方向,对砂体的分布也有明显控制作用。运用这些规律,可为在地震剖面上预测砂体提供有效约束。

Structural fault terrace zone incloses steep and gentle slopes.The control of the both kinds of slopes on sandbodies are different due to topography.During lowstand,alluvial fan,fan delta developed on steep slope while fluvial plain,small alluvial fan and fan delta developed on gentle slope.During progression period,fan head,midfan and far end of alluvial fan or fan delta devloped on different fault terraces,turbidite fan and gravity flow deposites developed on deep depressed position,while retrogradation of predepositional sandbodies developed on the gentle slope.During high stand,wedge and lense shaped deposits of delta progradation developed on the whole ares.Besides,fault activities and their migration directions also influenced the distribution of sandbodies.These regularities could be used to predict sandbodied on seismic profile.

10.11743/ogg19990305