3-D resistivity imaging of single-hole EM Data
Hung-Wen (Ocean) Tseng and Ki Ha Lee
Contact: Hung-Wen Tseng, 510/486-5502, HWTseng@lbl.gov
Research Objectives
Traditionally, electromagnetic (EM) induction logging has been widely
used for directly measuring the formation conductivity surrounding
uncased wells. Such a logging tool primarily consists of a magnetic
dipole transmitter and a receiver in a coaxial configuration, in
line with the borehole axis. As a result of this cylindrically symmetric
nature of source and receiver, induction logging data offers no
information about the 3-D conductivity distribution in the vicinity
of the borehole. We can only characterize the 3-D conductivity structure
surrounding a borehole if we can acquire multiple components of
the magnetic fields resulting from various source polarizations.
However, 3-D interpretations using such single-hole EM data are
difficult because of the richness and complexity of the data and
the very large number of discretized conductivity elements needed
to construct a realistic earth model. Taking advantage of the computing
efficiency of an algorithm based on a modified extended Born approximation
(MEBA), we have developed an algorithm for simulating and interpreting
EM data acquired in a single-hole environment.
To continue reading more about this project, view the
1-page pdf here.
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 Inverted conductivity structure centered at a borehole in the CO2 injection project site. Transmitter-receiver separation was 5 m; transmitter operating frequency was 6 kHz. Because of a vertical source, all three magnetic-field components were used for the inversion. The induction logging data is also displayed at the center for each panel for comparison.
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Inverted conductivity structure centered at a borehole in the CO2 injection project site. Transmitter-receiver separation was 5 m; transmitter operating frequency was 6 kHz. Because of a vertical source, all three magnetic-field components were used for the inversion. The induction logging data is also displayed at the center for each panel for comparison.