Naslov
Transformation of porosity into indicator dataset and interpretation of facies : Case study from Lower Pontian sandstone, Sava depression

Autori
Novak Zelenika, Kristina ; Malvić, Tomislav

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, sažetak, znanstveni

Izvornik
Abstracts of the XIII. Congress of Hungarian Geomathematics and the II. Congress of Croatian and Hungarian Geomathematics Applications of Geostatistics, GIS and Remote Sensing in the Fields of Geosciences and Environmental Protection / Geiger, Janos - Mórahalom : Hungarian geological society, Geomathematical section, 2009, 40-41

Skup
Congress of Hungarian Geomathematics (13 ; 2009) ; Congress of Croatian and Hungarian Geomathematics (2 ; 2009)

Mjesto i datum
Mórahalom, Mađarska, 21.05.2009. - 23.05.2009

Vrsta sudjelovanja
Poster

Vrsta recenzije
Međunarodna recenzija

Ključne riječi
porosity; indicator variable; indicator variogram; sandstone; Sava depression

Sažetak
There is a lot of variogram analysis performed in sandstones of Pannonian and Pontian ages in Sava depression. The most detailed variogram analysis and kriging mapping in the Sava depression had been performed in sandstones of Pannonian and Pontian ages (e.g. Balić et al., 2008 ; Malvić, 2008 ; Malvić and Balić, 2009). The input dataset included porosity data collected in 20 wells as average value of oil-saturated sandstone reservoir of Lower Pontian age. The minimum was 5.448% and maximum 23.282%. The presumption of analysis is that porosity values can indicate on different sandstone facies (like sandy marl, marly sand, fine-grained and medium-grained) and, of course, marl. It means that basic porosity set had been transformed in several indicator dataset, based on several cut-offs. There had been determined the following cut-offs: 12.5, 18.0, 18.5, 19.0, 19.5, 20.0, 20.5, 21.0, 22.0, 23.0 and 24.0%. For each ‘ integer’ dataset as well as for integral porosities is calculated variogram surface using Variowin 2.2.1 (Pannatier, 1996). The lag spacing was 400 meter both in X and Y direction and number of lags 6. These maps showed anisotropy (smaller variogram values) in direction NW-SE for the porosity, and the following cut-offs: 12.5 , 18.0 , 20.0 and 22.0. Due to not always clear anisotropy of variogram surfaces and relatively small number of data the variogram are calculated as omnidirectional. The variogram modelling is performed also by Variowin program, using lag spacing of 400 m and 8 lags in total. Variogram results will be base for mapping by Indicator Kriging in the next stage.

Izvorni jezik
Engleski

Znanstvena područja
Geologija

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