Geologic origin of the internal seismic reflection of marine strata in the Lower Yangtze region

doi:10.11743/ogg20110312

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Geologic origin of the internal seismic reflection of marine strata in the Lower Yangtze region
Vol. 32, Issue 3, Pages: 397-403(2011)
Online First：28 June 2011，

Published：2011
DOI： 10.11743/ogg20110312
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DOI：

Geologic origin of the internal seismic reflection of marine strata in the Lower Yangtze region[J]. 2011, 32(3): 397-403. DOI： 10.11743/ogg20110312.

摘要

下扬子海相地层地震内幕反射的资料品质区域上存在较大差异。通过对钻井资料、地层沉积成岩特征和地层速度分析，认为该区下古生界因成岩作用强烈，没有明显的速度界面，难以形成好的地震反射；而上古生界石炭-二叠系内部存在多个明显的速度界面，能形成较强的地震反射。海相地层地震内幕反射资料品质受石炭-二叠系的残存状况、构造变形等因素控制，在南黄海部分构造变形较弱地区，石炭-二叠系可以形成连续强反射；在苏皖陆上构造变形较强地区，主要形成断续反射；而在石炭-二叠系缺失地区，地震资料品质普遍较差，多为杂乱反射。有石炭-二叠系残存的地区和构造变形相对较弱的地区为地震攻关的主要目标区。

Abstract

Data quality of internal seismic reflection in marine strata varies greatly in different places in the Lower Yangtze area.Based on analysis of drilling data

sedimentation

diagenesis and strata velocity

we think that there is too strong diagenesis in the Lower Paleozoic to form any evident velocity interface and hence there are no obvious seismic reflections.While in the CarboniferousPermian of the Lower Paleozoic

there are several evident velocity interfaces to form intense seismic reflections.Residual condition of the CarboniferousPermian and structural deformation are the main factors to control the internal seismic reflection of the marine strata.There are continuous seismic interfaces due to weak structural deformation in parts of southern Yellow Sea and discontinuous seismic interfaces due to great structural deformation in the land of Jiangsu and Anhui provinces.But there is chaotic or jumble seismic reflection in areas without the CarboniferousPermian strata.The areas with the CarboniferousPermian strata and weaker structural deformation are the best places to do seismic survey.