Geoscience Australia Buys 10 New Phoenix UMT Systemsumt.phoenix-geophysics.com/pdf/PH62.pdf · generators to provide clients with cost savings, greater reliability and greater flexibility.
This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
Transcript
Geoscience Australia Buys 10 New Phoenix UMT Systems
Geoscience Australia (continued)GA’s LP-MT data showed evidence of broad
low-resistivity zones in the crust, which can
be interpreted as “mantle plumes” or prob-
able relict pathways of ascending fluids.
These “mantle plumes” are seen only at
macroscopic scale. When BMT data is added
to the LP-MT data, the resulting higher
resolution inversions coincide spatially with
known orebodies such as the well-known
Olympic Dam deposit.
This has energized a new way of thinking
about “mineral systems”, and highlights MT
as a key geophysical technique not just in
localized exploration, but also for tracing the
conductive relict fluid pathways in the crust.
GA’s diverse range of objectives and
depths (from surface to 100 km+) means
that the widest possible bandwidth MT
instrumentation is the most useful to GA.
In the past, it was difficult and/or costly
to acquire UMT data because two or even
three separate systems had to be deployed
sequentially.
The new UMT system captures all the re-
quired bandwidth in a single pass. UMT sys-
tem advantages include: basic interoperability
with older equipment; larger memory; lower
power; simplified, faster operations, process-
ing and calibrations; mitigation of MT static
shift by use of high frequency (~10 kHz) data;
avoidance of mismatch due to different cali-
brations and use of different sensors; optimal
capture of AMT deadband data at local mid-
night; uninterrupted time series without need
to switch magnetic sensors (or sensor modes)
from AMT to MT to LP-MT; improved inver-
sions and last, but not least, significant capital
cost and operating cost savings.
A powerful and flexible new software
package called EMPower – coded, main-
tained and under continuous development
by a team of professional software engineers
– is also provided. n
Durability An MTU-5C receiver emerges from a cold test at -25˚C.
Geophysicist Wenping Jiang of Geoscience Australia working with the new UMT system.
MTC-150 vs. Fluxgate The plot above shows resistivity and phase spectra from 10 kHz to 50,000 sec, from a 560-h (23 day) recording in Nevada, USA. The bright symbols show data from the new wideband MTC-150 induction sensor; the faint symbols show data from a fluxgate sensor LEMI-039, recorded simul-taneously with the 8-channel MTU-8A receiver. The MTC-150 results are the same as the fluxgate results at periods >100 seconds to ~25,000 sec. Both sensors provide noisy data at periods >25,000 sec due to tidal/diurnal effects. The fluxgate data diverges from MTC-150 data between 100 sec and 10 sec because the MT signal in this range during the recording was often below the fluxgate noise floor. MT signal strength cannot be predicted; therefore induction sensor data (with lower noise than the fluxgate) is more reliable in this range.
SEPTEMBER 2017 The Phoenix k Issue 62 3
PHOENIX AROUND THE WORLD
Canada 150: It is timely and suitable that Exploration’17 coincides
with Canada’s 150th anniversary. The first decennial conference,
Exploration ‘67, took place as a “Canada 100th birthday project in
1967. In the same positive spirit of innovation that characterized
the original Exploration’67 (and the Expo’67 World Fair in Mon-
tréal), Phoenix continues to introduce a wave of new technology as
the Phoenix innovation machine accelerates.
In a previous issue (Phoenix 61), we focused on the new wideband
magnetic sensor MTC-150. In this issue, we focus on the new
receiver technology – the MTU-8A and MTU-5C family – both of
which are interoperable with the current MTU-5A system via the
new software package EMPower, which we will describe in the
next issue. ~ Leo Fox
France As part of the Critex project (www.critex.fr/), a team from Pierre and
Marie Curie University (led by Dr. Christian Camerlynk) and a second
team from École et Observatoire des Sciences de la Terre (led by Dr. Pascal
Sailhac), worked together to purchase a complete 12-channel V8 system
with T-3 transmitter.
The scientists are using natural source and controlled source measure-
ments to study the “critical zone” – the thin surface layer of the Earth
where life evolved and resides – and where water, gases, and rocks all
interact. Critex aims to develop a holistic, cross-disciplinary understand-
ing of the critical zone.
Phoenix geophysicist Yann Avram traveled to Strasbourg, France in July
for training on, and acceptance of, the Phoenix system (right). According
to Dr. Sailhac, the ability of the system to display nine processed channels,
in real time, in the field, for CSAMT SIP, TDIP, and TDEM is cutting-edge,
and will improve the efficiency of their field operations.
Bolivia Long-time Phoenix client Nordwest of Moscow, Russia, won two
large-scale MT surveys in Bolivia for client YPFB-Andinas. These
surveys required wideband MT data using a single magnetic sen-
sor; Nordwest opted for the new MTC-150.
YPFB (the state-owned Bolivian oil company) operates sev-
eral divisions, including YPFB-Andinas. Andinas explores for oil
and gas in the eastern foothills of the Andes; the mountains and
foothills were created by compressional forces from the subduct-
ing Pacific Plate. In the foothills, sections of the “layer-cake” of
rocks have been forced on top of one another, with dense base-
ment rocks now atop less-dense hydrocarbon-bearing sedimen-
tary rocks. This geological structure (sometimes with very steep
bedding) is challenging for seismic exploration, hence the need
for MT.
The MT surveys operate in parallel with seismic surveys, us-
ing the same field camp to reduce cost. MT and seismic data are
interpreted together.
PRES IDENT ’ S MESSAGE
Djibouti Phoenix geophysicists have carried out three geothermal MT
surveys in Djibouti; shown during the the most recent survey are
Murat Urakov (right) installing an MT site on the typical steep and
rocky terrane and Caroline Finateu (below) checking equipment.