Seismic mono-frequency workflow for direct gas reservoir detection

A device comprising:

• a memory;
• and
• a processing unit that is arranged to perform operations including:
• spectrally decomposing seismic data associated with a target area into a plurality of mono-frequency volumes;
• based on (i) a low-frequency volume of the plurality of volumes, (ii) a reservoir interval in the target area, and (iii) a shadow zone in the target area, generating a low-frequency map of the target area;
• based on (i) a high-frequency volume of the plurality of volumes, generating a high-frequency map of the target area;
• dividing the low-frequency map by the high-frequency map to generate a frequency ratio map;
• identifying, in the frequency ratio map, a frequency ratio greater than a threshold frequency ratio;
• and
• determining that the identified frequency ratio is indicative of a subsurface gas reservoir in the target area.

A non-transitory computer-readable medium storing instructions executable by a computer system to perform operations comprising:

• spectrally decomposing seismic data associated with a target area into a plurality of mono-frequency volumes;
• based on (i) low-frequency volume of the plurality of volumes, (ii) a reservoir interval in the target area, and (iii) a shadow zone in the target area, generating a low-frequency map of the target area;
• based on (i) a high-frequency volume of the plurality of volumes, (ii) the reservoir interval in the target area, and (iii) the shadow zone in the target area, generating a high-frequency map of the target area;
• dividing the low-frequency map by the high-frequency map to generate a frequency ratio map;
• identifying, in the frequency ratio map, a frequency ratio greater than a threshold frequency ratio;
• and
• determining that the identified frequency ratio is indicative of a subsurface gas reservoir in the target area.