Naslov
Mapping of thin sandy aquifers by using high resolution reflection seismics and 2-D electrical tomography

Autori
Šumanovac, Franjo

Izvornik
Journal of applied geophysics (0926-9851) 58 (2006); 144-157

Vrsta, podvrsta i kategorija rada
Radovi u časopisima, članak, znanstveni

Ključne riječi
Water exploration; Electrical tomography; Seismic reflection; Electrical modelling

Sažetak
Electrical tomography, which gives good results even in fairly complex geological environments, has given a new lease of life to electrical methods in hydrogeological surveys. Nevertheless, a rapid decline in resolution with increasing depth remains the main problem of the electrical methods. In the Pannonian basin in Croatia, at a test area, combining both electrical tomography and seismic reflection methods provides data that better constrain the lithological and hydrogeological model of the subsurface. Electrical tomography revealed a rather thick packet of sediments with increased resistivity at depths of 40-100 m. Using the electrical forward modelling, the existence of two different hydrogeological models was shown. The first model presupposes a reasonably homogeneous packet of sandy clays or clayey sands, and the other model presupposes the alternation between layers of clays and sands. From the hydrogeological point of view, the second model is perspective, but unfortunately, the use of electrical tomography alone does not allow the ambiguity to be resolved. The separation of these two models became possible using seismic reflection. Three seismic environments were isolated from the seismic profile treated, and the strongest reflections were discovered in the first seismic environment, which covers the depths from 40 to 100 m. It was determined that the second model is more acceptable, because these reflections are caused by lithological changes, that is, the alternations of sands and clays. The interpretation is consistent with exploratory borehole data. The conclusion is that electrical tomography gives data concerning the sediment lithology up to depths of 40 meters, but at greater depths combined interpretation of electrical and seismic data constrains the subsurface model better.

Izvorni jezik
Engleski

Znanstvena područja
Rudarstvo, nafta i geološko inženjerstvo

Napomena
Doi:10.1016/j.jappgeo.2005.06.005

POVEZANOST RADA