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.