Patent ID: 8169222

Claim:
A method for designing a controlled-source electromagnetic survey of a subsurface region for resistive bodies, including receiver deployment, source line location, and source transmission parameters, said method comprising: a) developing a geological model of the subsurface region, said model comprising a deep, marginal target reservoir characterized by resistivity higher than background; b) selecting a source transmission frequency tailored to the depth of the deep marginal target reservoir; c) determining an initial survey design, specifying one or more source lines and one or more receiver locations, using the geologic model and the transmission frequency, and using as a criterion that the design must be able to discriminate between a model that includes the deep marginal target reservoir and a second model that is identical except that the target reservoir is replaced by background; d) specifying one or more additional A vs. B scenarios that the survey design must be able to discriminate upon inversion of the survey's electromagnetic field measurements in order to obtain a unique resistivity structure for the subsurface region; e) selecting an A vs. B scenario, and adapting the subsurface model as necessary to describe A and again to describe B; f) selecting an initial survey design including at least one selected transmission frequency; g) forward modeling data for the selected survey design from the previous step using the adapted models; h) obtaining a quantitative comparison of the forward-modeled data, A vs. B, at a plurality of (x,y) locations in the survey, resulting in a survey area coverage display for the selected survey design and scenario, wherein said quantitative comparison may be called a Null-Space Discriminating Ratio (“NSDR”); i) repeating steps (e)-(h) for any other scenarios specified in step (d); j) constructing at least one survey area coverage display based on NSDR values at the plurality of (x,y) locations in the survey; and k) choosing a final survey design based at least partly on the coverage displays and corresponding survey designs; wherein the number of variables affecting survey area coverage displays is reduced to a pre-selected number.