Objective Dim spots are those gas reservoirs located in relative deeper target strata in which seismic reflection energy remarkably goes down or disappear,and are thus quite difficult to recognize in comparison with the bright spots in conventional seismic interpretation due to their weak reflection amplitude.To pursue the amplitude nonsensitive indicators to brighten dim spot reservoirs,this work presents the stratal dispersion shadow(SDS)to Objective Dim spots are those gas reservoirs located in relative deeper target strata in which seismic reflection energy remarkably goes down or disappear, and are thus difficult to recognize in comparison with the bright spots in conventional seismic interpretation due to their weak reflection amplitude. To pursue the amplitude nonsensitive indicators to brighten dim spot reservoirs, this work presents the stratal dispersion shadow (SDS) to