Method for detecting frequency-variable gas in storage layer.

The invention provides a method capable of extracting a speed frequency dispersion effect from seismic data, achieving gas detection and gas-water identification in a rock storage layer by means of different speed frequency dispersion characteristics of a gas-containing storage layer and a water-containing storage layer. The method comprises: acquiring pre-stack seismic data of the storage layer; performing frequency division processing on the pre-stack seismic data in order to acquire the pre-stack seismic data body under each frequency; solving a following formula described in the description in order to acquire P wave speed variation rate frequency dispersion and S wave speed variation rate frequency dispersion of each sample point of the seismic channel of the storage layer; calculating a frequency-variable AVO attribute according to a relation among the P wave speed variation rate frequency dispersion, S wave speed variation rate frequency dispersion and the frequency-variable AVO attribute; and performing gas-containing state detection and gas-water identification on the storage layer according to the AVO attribute.