Naslov
Primjena fazne analize kod mjerenja poroziteta
(Implementation of the image phase analysis for porosity measurements)

Autori
Raškaj, Nevenka ; Djačanin, Dubravka ; Barbić, Zdenka ; Perković, Adaleta

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, prošireni sažetak, stručni

Izvornik
Knjiga sažetaka 4. Hrvatskog geološkog kongresa / - , 2010

Skup
4. Hrvatski geološki kongres s međunarodnim sudjelovanjem

Mjesto i datum
Šibenik, Hrvatska, 14.10.2010. - 15.10.2010

Vrsta sudjelovanja
Predavanje

Vrsta recenzije
Podatak o recenziji nije dostupan

Ključne riječi
poroznost, fazna analiza, porozimetar, okoliš taloženja, Pont
(porosity, image phase analysis, porosimeter, depositional environment, Pontian)

Sažetak
Porosity measurements were done in the well Okoli-24 in purpose for characterization of the Underground Gas Storage (UGS). Characteristics of reservoir rocks are based on sedimentological and petrophysical analysis of the cored interval 1859.0–1874.0 m. The Okoli field is located in the western part of the Sava Depression, approx. 50 km south-east of the capital Zagreb. Sedimentary and petrophysical results of the Pontian sandstones from the Okoli-24 well referred to 9m of the core samples, which is 60% of the total cored interval. The interval consists of the channel fill deposits represented with massive, medium to coarse grained, poorly sorted lithoarenites with eroded clasts of marls and coal, and nterchannel (swamp-lacustrine) thinly bedded to aminate pelites, i.e. clayey carbonates and marls with abundance of carbonaceous plant debris. The sediments from the analyzed interval were deposited in the flood or delta plain environment. Porosity measurements were done by Ultra Pore Porosimeter. Pore volume and bulk volume were determined by volumetric method using the laboratory equipment. Measurement is based on Boyle’s law of gas expansion. This method involves the expansion of nitrogen gas from a reference chamber of known volume into the pore space of the sample. Porosity of a sample is defined as a ratio of pore volume (Vp) and bulk volume (Vb) of the rock sample. Microporosity measurements were done by Image phase analysis computed program for Olympus polarization microscope with digital camera DP71. A phase analysis is a quantitative evaluation of area (mm2) with regard to each separate gray value or color phase for particle detection that is distinguishable from image background. All detected particle will be automatically measured (see phase Table 1). For analyses, thin sections must be previously prepared by blue dyed resin vacuum impregnation that is marked pore space. Microprosity measurements were done on the selected images (photomicrography) by applicable program for analyses. Results of analyzed thin sections by image phase analysis are mainly accordant with petrophysical measurements. Exception of microporosity values are proximately 0.5–3.0% and results are shown in Table 1. The porosity of sandstones ranges 15–22% and predominantly represented intergranular, somewhere intragranular porosity type. Lower values of porosity were affected by increasing of clay minerals (kaolinite, chlorite) and secondary carbonate cementation of pore space.

Izvorni jezik
Engleski

Znanstvena područja
Rudarstvo, nafta i geološko inženjerstvo

POVEZANOST RADA