Presentation on theme: "San Jose, California USA"— Presentation transcript:
1 San Jose, California USA Geometrics, Inc.45 years experience in making geophysical instrumentsSan Jose, California USADouglas Groom, Director of Geoelectrical Products
2 Geode EM3D New geophysical instrument for High-resolution CSAMT surveys (controlled source audio magnetotellurics) Minex Central Asia, April 2014 Astana, Kazakhstan
3 Geode EM3D Features What is it? Distributed network of up to forty EM receivers each have six channels for total 240 EM channelsEach receiver configurable for up to six telluric (E-field) channels and up to three magnetic (H-field) channelsDurable metal enclosure.Low noise front end as low as 10 nV/rtHzLow distortion front endAutomatic calibration in the fieldAutomatic contact resistance measurement in the fieldMuch more
4 HighlightsSynchronized electric and magnetic field measurements for CSAMT, AMT, and moreSynchronized by GPS to CSAMT transmitterRugged instrumentationReliable network architectureBacked by 45 years of experience in geophysical instrument manufacture
5 Geode EM3D 24-Channel Network 20 E – 4 H Channels
6 Benefits Why use it?High-density 3-D data sets for complete characterization of your mining prospectRapid data collection with all channels GPS-synchronized to a single transmitterFlexible spacing of H-field sensors to maximize resolution yet minimize costScalable network from 6 channels up to 240 channelsFull tensor CSAMT using two transmitter polarizationsAutomatic contact resistance measurement for better data qualityIn-field calibration for more accurate measurementFuture AMT, IP, Resistivity modules available
8 High-resolution, high-density EM data with many sounding stations at the same time (simultaneous data acquisition).Traditional CSAMT uses a separate setup for each sounding.For example, for 50 traditional CSAMT stations (soundings) the transmitter must be run fifty times and the station moved 50 times. Typically 30 minutes to one hour transmitter run time for each station meaning 50 hours of transmitter time for the survey, not including setup time.Geode EM3D allows a single setup of all stations and one transmitter run for acquisition of all 50 sounding at the same time (simultaneous acquisition). That is only 30 to 60 minutes in total for all 50 stations.
9 Orienting and leveling magnetic coils can be the most time consuming process in setting up a station
10 Geode EM3D offers flexibility in the use of H-field magnetic sensor coils Saves time: Traditional CSAMT requires burying coils for every sounding. Each time the station is moved the coils are reburied. Geode EM3D network allows using magnetic coils on one receiver to be used for multiple soundings on other receivers so fewer coils need to be buried.Improves efficiency: Operator can choose the optimal number of magnetic coils for the survey needs. For example H-field measurements can be used for every two E-field measurements, or maybe only every six, ten, or more E-field measurements, depending on the complexity of the geology and the requirements of the survey.Improves data quality: Using multiple Hy and Hx on different receivers, at different locations simultaneously, allows local referencing to improve data quality.
12 Easily scalable system from single-receiver 6-channel system to 40-receiver, 240-channel system Maximum flexibility in survey setup. Each receiver can be any combination of E and H up to six channels, such as:3E/3H4E/2H5E/1H6E
13 Field setup and channel parameters Note automatic contact resistance for every E-field dipole
14 GeodEM2010 Acquisition Menu Note “Measure Contact Resistance” and “Measure AC & DC Level” Contact resistance measured on automatically on all electrode channels. AC and DC noise level measured automatically.
15 China GeoTech BeijingIntroduction of multi-node Geode EM3D to Chinese
18 In-field screen display of test signal into 120 channel Geode EM3D
19 Better results with full tensor CSAMT Traditional CSAMT only does scalar (Ex/HY) impedance calculations. The Geode EM3D can easily do full-tensor measurements (Ex/Hy and Ey/Hx) using multiple polarizations from the controlled-source transmitter.
20 Geode EM3D field test approximately 100 km north of Beijing Four receiver network consisting of 20 channels used.Four magnetic (H-field) channelsSixteen electric (E-field) channelsFour channels not deployed
28 CSAMT field data 16 channels at 8 Hz with 1. 5 kW transmitter at 12 CSAMT field data 16 channels at 8 Hz with 1.5 kW transmitter at 12.5 km distance
29 CSAMT field data 16 channels at 8 Hz with transmitter at 12 CSAMT field data 16 channels at 8 Hz with transmitter at 12.5 km distance
30 Real-time CSAMT impedance curves for six soundings in field
31 CSAMT and AMT now with future, IP, resistivity and other methods in future The first Geode EM3D product is controlled source audio magnetotellurics (CSAMT). Future products plans include AMT (natural-field audio magnetotellurics), induced polarization (IP) resistivity and other geoelectrical techniques.
32 Setting parameters for AMT acquisition Note that seven channels defines tensor site Ex, Ey, Hx, Hy, Hz, Hx2 and Hy2 for local reference
33 AMT real-time times series field display (natural field with no transmitter)
39 System Configurations 1. Single NodeOne GeodeEM box used for AMT/CSAMT/IP with various configurations 6E, 5E1H, 4E2H, 3E3H2. “Typical” Small Networked SystemFour Geode EM3D receivers is the base network, with various configurations possible3. “Maximum” Networked System40 GeodeEM boxes, i.e. 240 channels.20 Geode EM networ of 110 on display in Laurel Geophysical booth in exhibition hall.