A method for surface estimation of reservoir properties, wherein location
of and average earth resistivities above, below, and horizontally
adjacent to the subsurface geologic formation are first determined using
geological and geophysical data in the vicinity of the subsurface
geologic formation. Then dimensions and probing frequency for an
electromagnetic source are determined to substantially maximize
transmitted vertical and horizontal electric currents at the subsurface
geologic formation, using the location and the average earth
resistivities. Next, the electromagnetic source is activated at or near
surface, approximately centered above the subsurface geologic formation
and a plurality of components of electromagnetic response is measured
with a receiver array. Geometrical and electrical parameter constraints
are determined, using the geological and geophysical data. Finally, the
electromagnetic response is processed using the geometrical and
electrical parameter constraints to produce inverted vertical and
horizontal resistivity depth images. Optionally, the inverted resistivity
depth images may be combined with the geological and geophysical data to
estimate the reservoir fluid and shaliness properties.