A method of removing fold effect for pre-stack time migration of merged data and its application
Qingling Wu, Lailin Li, Bin Chen · 2009
The effect of fold is very important for merging of different 3D seismic data sets, especially for pre-stack time migration because each survey block has different acquisition parameters(such as fold). When a uniform grid is defined for merged data processing of several surveys, it will result in fold increasing at the overlapping area of these surveys and inconsistent amplitude of pre-stack time migration data, and it even causes migration noises (smile phenomenon on the boundaries), which lead to decreasing migration quality. This paper applies a pre-stack amplitude normalized method based on fold to multiple-block-jointed pre-stack time migration for 19 survey blocks in Xujiaweizi Fault Depression of Daqing oilfield. Under the condition of preserving total seismic traces, it is effective in solving energy inconsistent problem in pre-stack time migration amplitude preserving, and the result is obvious.