Patent ID: 8386182

Claim:
A method for prospecting for hydrocarbons in a subsurface region using the results of a controlled-source electromagnetic survey, comprising: (a) obtaining measured electromagnetic data from a survey of the subsurface region, said survey having used at least one source waveform that was selected or designed by steps comprising: (i) defining a plurality of resolvable depth units within the subsurface region; (ii) for each depth unit, calculating an optimal frequency for penetrating to that depth; (iii) estimating noise levels at each optimal frequency; (iv) determining a minimum source amplitude at each optimal frequency in consideration of the estimated noise; and (v) selecting or designing at least one source waveform whose frequency spectrum, or combined frequency spectra if more than one source waveform, contains all optimal frequencies determined in (ii), within a pre-selected tolerance, with associated amplitudes substantially the same as or greater than the minimum amplitudes determined in (iv); (b) constructing an earth model of the subsurface region using electromagnetic data measured in the survey, said constructing being performed using a computer; and (c) predicting hydrocarbon potential of the subsurface region at least partly from the earth model.