According to deep burial depth, uneven oil and gas distribution of carbonate reef flat lithologic reservoir of Changxing Formation in BL area, this paper put forward a train of thought for hydrocarbon detection which combined frequency attenuation attributes and low frequency ad joint-shadow phenomenon. This paper first introduced the principle of frequency attenuation attributes and low frequency ad joint-shadow phenomenon; secondly established geological model combined with the reservoir physical parameters of Changxing Formation in BL area, and simulated and analyzed the seismic response characteristics of the reservoir by using viscosity-diffusivity wave equation. The model analysis result shows that it is feasible to detect gas-bearing properties of reservoir by using frequency attenuation attributes and low frequency ad joint-shadow phenomenon. Application of real data demonstrates that frequency attenuation attributes and low frequency ad joint-shadow phenomenon has good instruction to the reservoir, and improved the accuracy of reservoir prediction and fluid detection, which can provide a way for oil-gas identification and
fluid detecttion of carbonate reef flat lithologic reservoir and similar reservoirs of Changxing Formation in BL area.