【摘要】 根据单井沉积旋回对比,结合地震反射特征分析,本文将青山口组划分为3个三级层序,8个四级层序。四级层序界面主要有:1)河道冲蚀底界,表现为砾石层或砂砾岩层、内碎屑泥砾、钙砾或生物成因的灰质河道滞留物,测井曲线多为钟形;2)地表暴露面,表现为根土岩、古土壤层、紫红色泥岩或杂色泥岩、岩相突变带以及钙质结核层,测井曲线多为漏斗形;3)沉积物卸载区和滨岸带,出现钙质砂岩层、介形虫层等特殊沉积,测井曲线多具指形特征。层序界面的地震响应特征有:1)近物源的上坡折区,地震波组表现为削截或冲刷充填;2)坡折带发育区,地震波组表现为上超,亦见下超和顶超;3)强振幅反射同相轴所示的上、下地层的截然差异;4)地震波阻抗反演剖面波组上、下的截然差异等。松辽盆地北部青山口组的四级层序的划分及界面识别,为进一步建立四级层序格架奠定了基础。更多还原

【Abstract】 Based on sedimentary cycle correlation of single well and analysis of seismic reflection characters,Qingshankou Formation in the northern Songliao Basin was divided into three third- order sequences and eight fourth-order sequences.The main fourth-order sequence boundaries were as follow:1) channel erosion bottom,showing as gravel beds,glutinite beds,intraclast mud pebble,calcigravel or biogenesis limy channel lag deposit,with campaniform logging curve,2) surface exposure,showing as seat stone,ancient soil beds,mauve-varicoloured mudstone,litho- facies abrupt change and calcareous concretion beds,with logging curve being infundibuliform- shaped,and 3) sediments download area and lake-board,having particular sediments such as calcareous sandstone and ostracoda beds,with dactyline logging curve.The seismic response features of sequence boundary were as follow:1) near provenance and upper slope break,seis- mic train of waves showing as truncated or washing-filling reflectors,2) slope break area,seis- mic train of waves showing as onlap,sometimes downlap or toplap,3) sharp difference between upper and lower stratum shown by high amplitude reflection event,and 4) sharp difference be- tween upper and lower train of waves on seismic wave impedance section.The dividing and boundary recognizing of the fourth-order sequence laid the foundation to further establish the fourth-order sequence framework for Qingshankou Formation in the northern Songliao Basin.更多还原