Abstract:
The Ganquan Loess Plateau Block in the Ordos Basin exhibits promising hydrocarbon exploration potential in its karst reservoirs. However, the seismic imaging quality obtained using conventional methods remains suboptimal due to challenges posed by thick loess layers and complex karst reservoir structures. This paper proposes a dip-angle domain stationary-phase deabsorption prestack time migration method to enhance imaging quality in this area. By incorporating the effective
Q concept, the method compensates for seismic wave energy attenuation and wavelet dispersion caused by medium absorption, significantly improving imaging resolution. Nevertheless, high-frequency energy compensation inevitably amplifies migration noise. The dip-angle domain stationary-phase migration estimates the Fresnel zone based on dip-angle gathers, achieving optimal Fresnel zone stacking imaging in the dip-angle domain, which effectively suppresses migration noise and substantially enhances the signal-to-noise ratio (SNR) of the imaging section. The proposed method integrates the dual advantages of dip-angle domain stationary-phase migration (improving SNR) and viscoelastic prestack time migration (enhancing resolution). After applying this method to the Ganquan Loess Plateau Block, both the SNR and resolution of imaging profiles were markedly improved, with the typical "beaded" structures in karst reservoirs clearly imaged.