Low frequency shadows is one of hydrocarbons indicators. It can be
detected by means of a time-frequency decomposition which can provide higher
frequency resolution at lower frequencies and higher time resolution at higher
frequencies. This is des
irable for analyzing seismic data, because the
hydrocarbons in reservoir are diagnostic at lower frequencies. we have carried
out such analyses with post-stack data sets on Fahda field which is located in
Aleppo uplift, it contains oil. Adding a frequency axis to a 2D seismic section
makes the data 3D axis. The comparison of the single frequency sections from
such 3D volume can be utilized to detect low frequency shadows. A
preferentially illuminated single frequency section at lower frequencies from
Fahda field, shows high amplitude low frequency anomalies beneath oil zones.
These anomalies disappear at higher frequencies.
