3DGEm: geological mapping for 3D geothermal exploration

Abstract

3DGEm is presented as a unique and innovative tool for creating high-resolution 3D geological
maps that can benefit geothermal exploration. Faint natural electromagnetic waves ae
converted into two data modes: Mode A that shows EM inductance index to represent
geological materials, and Mode B that displays anisotropic EM impedance coefficients whose
progressive increase with depth is perturbed by faults, geological boundaries, and perhaps
even temperature and permeability variations. While 3DGEm involves geophysical
instruments and procedures, its two data modes portray qualitative and empirical
representations of subsurface geology. The interplay between materials—mapped in Mode A,
and structures—revealed in Mode B, graphically illustrates the dynamics of geothermal
systems. Faults, alteration zones, perhaps even permeability and elevated temperatures, are
implied by the textures and structures displayed by the impedance coefficient, whereas zones
of EM inductance indices chart subsurface physicochemical features. The proxy geophysical
attributes shown in 3DGEm charts reflect the geological environment to depths of a few
kilometers.

Introduced in November 2024, the 3DGEm technology is currently multi-nation patent-
pending. Although some permutations of its multi-sensor attributes are still to be unraveled,

the simple unsupervised plots of 3DGEm data, by themselves, can already provide intuitive
and highly-detailed geological models. When coupled with other field data, geothermal
exploration can therefore immediately benefit from 3DGEm’s high-resolution 3D geological
images, without resorting to artificial intelligence, hypothetical modelling or a stretch of the
imagination.