摘要 应用三维地震及测井地质剖面,在松辽盆地大庆长垣地区嫩江组二段发现3套滑塌扇体,北部LMD扇体由5个单体组成,垂向呈前积式交叉叠置,总体呈前缘外凸的铲状,近东西走向,最大面积约为95 km2,最大厚度为62 m; 南部MX扇体由7个单体组成,垂向交叉叠置,平面镶嵌连片,总体走向北北东,总覆盖面积约为61.5 km2,最大厚度为55 m; 中部的SET为独立扇体,呈半圆形,近东西走向,面积约为24 km2,最大厚度为92 m; 3套扇体均具有根部厚、前端薄的发育特征,而且前端以发育泥岩为主,中部及根部发育2～4层粉砂岩,厚度为0.8～7.0 m; 3套扇体及其单体表面均具有弧形地震反射波纹,波纹密度分布在4～10条/km; 推测3套扇体最小古坡度为5‰～12‰,最小古水深为30～70 m,滑移距离为2～10 km; 这一发现为在大型陆相坳陷湖盆中研究滑塌浊积扇体的沉积学特征提供了有利的证据,同时南部MX扇体已经发现工业油流,因此,这一发现也为在坳陷盆地湖相泥岩中寻找油藏提供了新的思路。
Based on 3D seismic and log curves geological cross section,we have discovered three sets of slump turbidite fans in the second member of the Nenjiang Formation of Daqing Placanticline of the Songliao Basin.The northern fan-LMD fan is composed by five single fans,which are cross-superimposed and foreset in the vertical direction.LMD fan are a convex shovel shape in the front and nearly WE trend,and the maximum area is about 95 km2,the maximum thickness is 62 m.The southern fan-MX fan comprises seven single fans,which are cross-superimposed in the vertical direction,and mosaic and contiguous from the plain view.MX fan is NNW strike,and its total affected area is around 61.5 km2,and the maximum thickness is 55 m.The central SET fan is an independent fan,semi-circular shape,and nearly WE strike,with the area of 24 km2 and the maximum thickness of 92 m.Three sets of fans are thick at its roots,and thin at its front.There are mainly mudstones in the frontal splay, 2～4 layers of siltstones in the middle and at the root,with the thickness of 0.8～7.0 m.The surface of three sets of fans and single fans have arc-like seismic reflected ripple wave,and ripple density is 4～10 waves per kilometer; we have predicted that the palaeoslope of the three sets of fans is 5‰～12‰ at least,the minimum depth of water is 30～70 m,and the sliding distance is 2～10 km.This discovery provides strong evidence for studying deposition characteristics of slump turbidite fans in the large-scale depression continental basin and provides a new way for searching reservoirs in the depression lacustrine mudstone basin since industrial oil current have been found in southern MX fan.
. Discovery of slump turbidite fans of the second member of the Nenjiang Formation and its implication on petroleum geology of Daqing Placanticline of the Songliao Basin[J]. Chinese Journal of Geology, 2012, 47(1): 129-138.