The GF6 seismo-electric survey instrument is designed specifically for detecting electrical signals generated by the passage of seismic impulses through layered rocks, sediments and soils. Its design is portable, rugged and simple. The remarkably high signal to noise ratios achieved with the patented design means that productivities are high; up to twenty water well or oil well sites or more can be surveyed by one operator in a day of work. Over eighty units have been sold to businesses and research organizations around the world. Most are used for groundwater and well water investigation but some are used for civil and environmental engineering work, research, and minerals exploration. Dozens of operators have used these units to find well water for farmers, home owners, land developers and anyone who needed to find well water before going to the significant expense of drilling a water well. The quality and potential quantity of the aquifer is estimated by semi-empirical relationships established between signal bandwidth and amplitude and aquifer permeability. These are supported by thousands of observations over the past decade. This system has been effectively used to locate groundwater for well water development across North America, New Zeeland, Australia, Africa, the Middle East and Europe. It is also possible to estimate water table depth but most people who use these services want to know approximately how deep to drill and approximately how much water they can expect from their new water well. Systematic surveys along traverses or in grids allow the lateral variability of aquifers to be mapped. Contact us or visit www.findwellwater.com for more information.
The developers of the GF6 set has adapted it for deep investigations and has shown that because of the focused, radial symmetry of seismo-electric signals radiated by plane interfaces deep signals are unexpectedly strong. We have observed signals, possibly from hydrocarbon/water contacts, at travel times corresponding to depths of approximately 1400m using only a small cartridge source onshore and a small single air gun offshore. We are currently adapting the equipment for the detection and use of such signals as direct hydrocarbon indicators and are marketing the equipment as SEP (seismo-electric equipment for petroleum). Contact us if you are interested, either for exploration, or for helping to locate infill wells in laterally discontinuous oilfield reservoirs.
The GF6 and a seismic source are used together to generate and collect the seismoelectric signal. The seismic source is used to create a sound wave (pulse). When the sound wave moves through aquifers the water in the aquifer moves relative to the rock formation. Ions in the water are dragged away from their partners bound to the rock and the electrical disturbance created travels to the surface at the speed of light and is detected by the antenna array. Each signal is separated in time from its neighbors by the propagation time of the down going seismic pulse. This gives unambiguous depth and thickness data, as with reflection seismic. The form of each signal gives information about the depth, thickness and quality of the aquifer and this is used to estimate the likely yield from a water well drilled at the survey site.
Independent observations of the seismoelectric system:
In 2006, a Geologist named B. Kulessa from the University of Belfast contributed to a paper on the uses of the Groundflow EKS seismoelectric system used for the exploration of glaciers. The paper is title “Active seismoelectric exploration of glaciers” and can be found on the American Geophysical Union website (www.agu.org). Below are excerpts from the paper:
“Repeatable and strong seismoelectric signals were recorded on Glacier de Tsanfleuron, Switzerland, using a vertical sounding geometry.”
“The present study is motivated by the recent rapid advances in the development of seismoelectric techniques, and recognises that they potentially have unique capabilities in detecting and mapping layers within and beneath ice masses, in characterising the hydraulic or fluid properties of such layers, and in monitoring a variety of glacial processes associated with ice fracture or basal dynamics.”