Acquiring a comprehensive 3D IP/resistivity field data set.



Survey example: The expected target lies between 400 m and 600 m below surface.
(Note - this example is scalable: for a target depth of 80 m to 120 m, divide all depth and Ze values by 5).

To objectively image (using standard 3D data inversion) a drill target that extends to a true depth of 600 m,
a sufficiently dense, uniformly distributed field data set is required, to an effective depth (Ze) of 900 m.
Then, to verify the presence of a lower limit for the 600 m anomaly, i.e. either to cut it off or to
establish its continuation beyond 600 m, even deeper field data need to be acquired, to a Ze of 1200 m,
in order to effectively define the depths between 600 and 800 m below surface. Failure to constrain the
lower edge of the targeted anomaly (by supplying these deeper field data) leaves the 3D inversion free
to simply extrapolate downward. The 3D model result is a technically "good fit to the data set", but
in fact, one would be targeting drilling on a 3D model result that is effectively unconstrained by hard data.

The following three images show how a 3D E-SCAN builds the required fully-constraining field data set:
all-directional, uniformly distributed, and sufficiently deep, in this case to the required Ze =>1200 m.


First current injection "shot" of a field survey



Figure 1:     Current is injected at the first station of the first line of the survey grid, for six types of DC IP/resistivity field surveys.
Also shown is a line of CSAMT resistivity stations, measuring a single orientation field originating from a single distant source.


Ten shots down the survey line



Figure 2:     The data acquired after current has been advanced ten stations down a line.


Completed survey: the acquired data set.



Figure 3:     Typical completed-survey field data sets, ready for constraint of 3D inversion modeling.

TITAN-24 survey data are shown at right; other collinear surveys will show similar adjacent lines of data (per Figure 2, above)
spread across the survey area. A true 3D survey application respects the possibility that various unknown possibilities may
exist, as exemplified by the overprinted deep structural pattern. While both of the above survey data sets will support imaging
of the predicted east-west (left-right) structure and/or anomalous body orientation, any unexpected cross-breaking structure and
anomalous bodies oriented north-south will be mapped with equal objectivity only by an all-directional data set, example at left.

TITAN-24's true 3D equivalent technology, ORION 3D, can deliver all-directional 3D data sets that look similar to those shown at left.
A point-by-point comparison of 3D E-SCAN and ORION 3D methods, costs, and limitations can be reviewed: click here.