HYDROGEOLOGICAL MAPPING OF A MIOCENE AQUIFER BY TWO-DIMENSIONAL ELECTRICAL IMAGING
Item
Title (Dublin Core)
eng
HYDROGEOLOGICAL MAPPING OF A MIOCENE AQUIFER BY TWO-DIMENSIONAL ELECTRICAL IMAGING
hrv
HIDROGEOLOŠKO KARTIRANJE MIOCENSKOG VODONOSNIKA DVODIMENZIONALNOM ELEKTRIČNOM TOMOGRAFIJOM
Description (Dublin Core)
eng
Geoelectrical resistivity methods have been playing very important role in hydrogeological explorations for years, since they can provide information lithology porosity, permeability and water quality. But conventional resistivity methods, electrical sounding and electrical profiling, cannot satisfy demand for continuos coverage over an exploration area and for building of a detailed hydrogeological model, especially with complex geological models and 3-D structure shapes. Electrical sounding is based on a theoretical assumption of a horizontally stratified earth model, and electrical profiling maps only lateral resistivity changes at the same depth. Two-dimensional (2-D) electrical imaging (or 2-D electrical tomography), that has been introduced recently, can map the both vertical and lateral resistivity changes and provides for building three-dimensional (3-D) resistivity model of the underground.
Exploration has been carried out in the area of the Seona spring to investigate the possibility for pumping more water during dry season, from the well located near the spring. The water of the Seona spring emerges from Badenian carbonate aquifer, which shows irregular 3-D shape and heterogeneous lithologic composition. A network consisting of four electrical profiles has been established to acquire a 3-D resistivity model, which can be transformed in a 3-D hydrogeological model. Inverse resistivity model sections revealed high resistivity zone which has been correlated with Badenian limestone by means of existing outcrops. Low resistivity zones point to the marly layers. Exploratory borehole located on the basis of electrical data has confirmed derived hydrogeological model from the electrical imaging data. Heterogeneous limestone aquifer has been uncovered at depth 8.2 – 55 m. The aquifer is weathered and karstificated with two main cavern intervals.
Hydraulic connections between the caverns and the spring have been established during drilling, but also in a pump test by means of the airlift method.
The presented case demonstrates great possibilities of the electrical imaging method in mapping of irregularly shaped aquifers and building of a precise 3-D hydrogeological model.
Exploration has been carried out in the area of the Seona spring to investigate the possibility for pumping more water during dry season, from the well located near the spring. The water of the Seona spring emerges from Badenian carbonate aquifer, which shows irregular 3-D shape and heterogeneous lithologic composition. A network consisting of four electrical profiles has been established to acquire a 3-D resistivity model, which can be transformed in a 3-D hydrogeological model. Inverse resistivity model sections revealed high resistivity zone which has been correlated with Badenian limestone by means of existing outcrops. Low resistivity zones point to the marly layers. Exploratory borehole located on the basis of electrical data has confirmed derived hydrogeological model from the electrical imaging data. Heterogeneous limestone aquifer has been uncovered at depth 8.2 – 55 m. The aquifer is weathered and karstificated with two main cavern intervals.
Hydraulic connections between the caverns and the spring have been established during drilling, but also in a pump test by means of the airlift method.
The presented case demonstrates great possibilities of the electrical imaging method in mapping of irregularly shaped aquifers and building of a precise 3-D hydrogeological model.
hrv
Geoelektrične metode otpornosti imaju važnu ulogu u hidrogeološkim istraživanjima već godinama, jer mogu dati litološke podatke i s tim povezane šupljikavost i propusnost, ali i podatke o mogućoj zaslanjenosti vode. Međutim klasične metode otpornosti, geoelektrično sondiranje i geoelektrično profiliranje, ne mogu udovoljiti zahtjevu za kontinuiranim pokrivanjem istražnog područja i za konstruiranjem preciznog hidrogeološkog modela, napose u složenim geološkim modelima i trodimenzionalnom obliku struktura. Geoelektrično sondiranje se osniva na pretpostavci horizontalno uslojenog modela podzemlja, a geoelektrično profiliranje može kartirati samo lateralne promjene otpornosti na istoj dubini. Dvodimenzionalno (2-D) električno mjerenje (ili 2-D-električna tomografija), koja se nedavno pojavila, može kartirati i okomite i uzdužne promjene otpornosti i tako omogućiti konstruiranje trodimenzionalnog modela otpornosti podzemlja.
Istraživanje je provedeno na području izvora Seona, kako bi se istražila mogućnost zahvata veće količine vode iz bušotine u okolici izvora, napose u sušnim razdobljima. Voda u izvoru Seona istječe iz badenskog karbonatnog vodonosnika koji je nepravilnog trodimenzionalnog oblika i heterogenog litološkog sastava. Postavljena je mreža od četiri profila kako bi se dobio trodimenzionalni model otpornosti, koji se može preoblikovati u trodimenzionalni hidrogeološki model. Interpretirani dvodimenzionalni modeli otpornosti su otkrili zone visokih otpornosti koje se mogu korelirati s badenskim vapnencima na izdancima. Zone niskih otpornosti ukazuju na laporovite slojeve. Istražna bušotina locirana na temelju geoelektričnih podataka potvrdila je hidrogeološki model načinjen na temelju podataka električne tomografije. Heterogeni vapnenjački vodonosnik otkriven je na dubinama 8.2-55 m. Vodonosnik je karstificiran i trošan, s dva glavna kavernozna intervala. Utvrđena je hidraulička veza između bušotine i izvora još tijekom bušenja, a napose pokusnim crpljenjem metodom “air-lifta”.
Izloženi primjer pokazuje velike mogućnosti metode električne tomografije u kartiranju vodonosnika nepravilnih oblika i definiranju preciznog trodimenzionalnog hidrogeološkog modela
Istraživanje je provedeno na području izvora Seona, kako bi se istražila mogućnost zahvata veće količine vode iz bušotine u okolici izvora, napose u sušnim razdobljima. Voda u izvoru Seona istječe iz badenskog karbonatnog vodonosnika koji je nepravilnog trodimenzionalnog oblika i heterogenog litološkog sastava. Postavljena je mreža od četiri profila kako bi se dobio trodimenzionalni model otpornosti, koji se može preoblikovati u trodimenzionalni hidrogeološki model. Interpretirani dvodimenzionalni modeli otpornosti su otkrili zone visokih otpornosti koje se mogu korelirati s badenskim vapnencima na izdancima. Zone niskih otpornosti ukazuju na laporovite slojeve. Istražna bušotina locirana na temelju geoelektričnih podataka potvrdila je hidrogeološki model načinjen na temelju podataka električne tomografije. Heterogeni vapnenjački vodonosnik otkriven je na dubinama 8.2-55 m. Vodonosnik je karstificiran i trošan, s dva glavna kavernozna intervala. Utvrđena je hidraulička veza između bušotine i izvora još tijekom bušenja, a napose pokusnim crpljenjem metodom “air-lifta”.
Izloženi primjer pokazuje velike mogućnosti metode električne tomografije u kartiranju vodonosnika nepravilnih oblika i definiranju preciznog trodimenzionalnog hidrogeološkog modela
Creator (Dublin Core)
Šumanovac, Franjo
Urumović, Kosta
Dragičević, Ivan
Subject (Dublin Core)
eng
resistivity methods;two-dimensional electrical imaging;hydrogeology;Miocene aquifer
hrv
metode otpornosti;dvodimenzionalna električna tomografija;hidrogeologija;miocenski vodonosnik
Publisher (Dublin Core)
Faculty of Mining, Geology and Petroleum Engineering University of Zagreb
Date (Dublin Core)
2003
Type (Dublin Core)
text
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
Format (Dublin Core)
application/pdf
Identifier (Dublin Core)
https://hrcak.srce.hr/13384
eng
https://hrcak.srce.hr/file/20509
Source (Dublin Core)
Rudarsko-geološko-naftni zbornik
ISSN 1849-0409 (Online)
Volume 15
Issue 1
Language (Dublin Core)
eng
Rights (Dublin Core)
info:eu-repo/semantics/openAccess
The author and publisher rights are visible during the submission process, and ethical codex is available at http://hrcak.srce.hr/ojs/index.php/rgn/about/editorialPolicies#custom-0 .
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Publisher copyright policies & self-archiving is also described at Sherpa organisation web (RoMEO service) based at the University of Nottingham (http://www.sherpa.ac.uk/romeo/pub/2374/).
All volumes of the Bulletin (from 1989) are available at Hrčak journal pages (http://hrcak.srce.hr/rgn-zbornik?lang=en).
The Bulletin is open access (OA, green model, CC-BY) journal what means that electronic versions of articles are accessible to readers, without any fees or registration.When use, please refer to Creative Commons license (BY type, http://creativecommons.org/licenses/by/4.0/ ).
Publisher copyright policies & self-archiving is also described at Sherpa organisation web (RoMEO service) based at the University of Nottingham (http://www.sherpa.ac.uk/romeo/pub/2374/).
All volumes of the Bulletin (from 1989) are available at Hrčak journal pages (http://hrcak.srce.hr/rgn-zbornik?lang=en).