A method of locating subsurface hydrocarbon reservoirs includes acquiring seismic data, dividing the seismic data into time windows, applying a data transform to the seismic data having a plurality of components to obtain a smoothed frequency spectrum, selecting one or more local maxima and minima, determining a frequency product as a function of the maxima and minima in a form for display. Lower and higher ratio thresholds may be selected to further discriminate frequency product selection for display. A display or map of frequency products over a survey area may indicate the presence of subsurface fluid reservoirs.