Wyniki wyszukiwania - Biblioteka Nauki

1

Quantitative Evaluation of Porosity in Turbine Blades Made of IN713C Superalloy After Hot Isostatic Pressing

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Roskosz S.

Archives of Metallurgy and Materials

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2017

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tom Vol. 62, iss. 1

253--258

EN

The aim of this paper is an assessment of the influence of hot isostatic pressing treatment on porosity of cast samples - turbine blades and vane clusters made of the IN713C superalloy. Two variants of HIP treatments, differing in pressure from each other, have been used. The quantitative evaluation of the porosity was performed using light microscopy and quantitative metallography methods. The use of the hot isostatic pressing significantly decreased the volume fraction and size of pores in the test blades, the remaining pores after the HIP process being characterized by a round shape. The increased pressure has caused significant reductions in the area fraction and size of the pores.

2

Series solution of unsteady free convection flow with mass transfer along an accelerated vertical porous plate with suction

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Zaman H. , Ayub M.

Open Physics

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2010

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tom 8

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nr 6

931-939

EN

The problem of unsteady free convection flow is considered for the series solution (analytic solution). The flow is induced by an infinite vertical porous plate which is accelerated in its own plane. The series solution expressions for velocity field, temperature field and concentration distribution are presented. The influence of important parameters is seen on the velocity, temperature, concentration, skin friction coefficient and temperature gradient with the help of graphs and tables. Convergence is also properly checked for different values of the important parametes for velocity field, temperature and concentration with the help of ħ-curves.

3

Zastosowanie sztucznej sieci neuronowej do uzupełnienia danych zbiornikowych

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Darłak B. , Włodarczyk M.

Przegląd Geologiczny

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2001

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tom Vol. 49 nr 9

797-803

PL

Przedstawiona praca jest poświęcona nowej metodzie zastosowania sztucznej sieci neuronowej (ANN) w zagadnieniach geologicznych takich jak ocena własności zbiornikowych skał węglanowych w oparciu o wyniki mikroskopowej analizy obrazu, a także odtworzenie przebiegu krzywych przepuszczalności względnej dla kilku typów piaskowców. Za pomocą ANN przeprowadzono analizę możliwości ekstrapolacji wyników badań laboratoryjnych przepuszczalności względnych i komputerowej analizy obrazu. Jako parametry bazowe do symulacji neuronowych wykorzystano wyniki badań porozymetrycznych wraz z analizą krzywych ciśnień kapilarnych oraz przepuszczalność liniową. Stwierdzono że poprawnie skonstruowana baza danych oraz wykonanie rzetelnych statystycznie oznaczeń przepuszczalności fazowej i komputerowej analizy obrazu, a także mikroskopowych analiz na płytkach cienkich umożliwia poprawną ekstrapolację oczekiwanych parametrów. Poprawność symulacji ANN sprawdzono wykonując serie testowych analiz Korelacja danych pomierzonych i wyliczonych ANN jest wysoka i wynosi odpowiednio w 0,98 symulacjach parametrów komputerowej analizy obrazu i 0,89 w symulacjach parametrów przepuszczalności względnych, co jest wystarczającym warunkiem do zastosowania tej metody w dalszych badaniach.

EN

This paper deals with a new method of using Artificial Neural Network (ANN) in solving various geological problems, including reservoir properties assessment of carbonate rocks derived from results of microscopic analysis of images, as well as from reconstruction of relative permeability curves for several sandstone types. Based on ANN, the relative permeability data and results of numerical parameterisations of microscopic analyses of images were perfomed. Porosity permeability, and other parameters, i.e. threshold pressures, specific surfaces and density, obtained during capillary pressure analyses were applied as a database. These studies indicate that the reliable database and properly prepared series of measurements result in good quality of extrapolation of relative permeability and microscopic analysis parameters. In both cases the use of ANN produces good results. The correlation coefficient of experimental and simulated data is high amounting to 0.98 (computer microscopic analysis) and 0.89 (relative permeability), which enable using this method for further investigations.

4

Możliwości oceny porowatości jako skutku zjawisk powierzchniowych w odlewach z metalowych kompozytów z nasycanym zbrojeniem

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Gawdzińska K. , Jackowski J.

Archiwum Technologii Maszyn i Automatyzacji

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2004

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tom Vol. 24, nr 1 sp

67-77

PL

Porowatość odlewów z metalowych kompozytów z nasycanym zbrojeniem w dużej mierze jest skutkiem zjawisk powierzchniowych, które towarzyszą ich wytwarzaniu. Przeprowadzono badania, których celem była ocena całkowitej porowatości próbek kompozytowych metodą grawimetryczną i metodą analizy obrazu, a także identyfikacja porów w strukturze odlewów. Porównanie wyników badań wykazało, że badania grawimetryczne zapewniają bardziej wiarygodną ocenę aniżeli metoda analizy obrazu zgładu metalograficznego. Metalograficzna ocena badanych struktur kompozytowych (z użyciem zróżnicowanych powiększeń) umożliwia jakościową klasyfikacją porowatości i jest przydatna w działaniach korygujących nasycanie zbrojenia w celu ograniczenia porowatości odlewów.

5

Wyznaczanie powierzchni właściwej materiałów ziarnistych w aspekcie stosowania jej wielkości w wybranych procesach technologicznych

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Radomski P. , Jarosiński A.

Czasopismo Techniczne. Chemia

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2010

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tom R. 107, z. 1-Ch

267-276

PL

W artykule dokonano porównania wybranych metod wyznaczania powierzchni właściwej materiału ziarnistego. Zwrócono uwagę na zasady oznaczania powierzchni właściwej ze składu ziarnowego. Ustosunkowano się do wyboru metod określania powierzchni właściwej materiałów ziarnistych.

EN

Selected methods of specific surface area determination of the granular material were compared in this paper. Specific surface area was examined for different material granulations. The methods of specific surface area determination were analyzed and discussed for different grain size materials.

6

Experimental Determination of Anisotropy Coefficients for a Wood

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Berdychowski M. , Matyjaszczyk M. , Mielniczuk J.

Machine Dynamics Research

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2010

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tom Vol. 34, No. 1

14-22

EN

A special form of the yield condition of porous anisotropic materials, such as a wood containing the wood humidity, is a function of the modulus of elasticity, the modulus of humidity and anisotropy coefficients. It is necessary to determine anisotropy coefficients to develop this equation for engineers. A measuring laboratory and a methodology of experimental determination of anisotropy coefficients for a wood are given in the paper.

7

Diagnosing the porosity and liquid permeability of large-pore grinding wheels

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Niżankowski C.

Journal of Machine Engineering

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2008

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tom Vol. 8, No. 2

86--94

EN

The paper presents a new method of diagnosing the porosity and liquid permeability of large-pore grinding wheels, consisting in the application of computer tomography, image analysis and finite elements method. This method was developed at the Faculty of Mechanical Engineering, Cracow University of Technology in 2006, and is covered by patent protection (P-382829). The method enables diagnosing the grinding wheel porosity not only as regards the percentage share of pores in entire grinding wheel capacity but also their number, shape, length and net of small ducts made by them. It also makes it possible to diagnose permeability of a large-pore grinding wheel without the need to run labour- and cost-consuming experiment tests.

8

Dimensions of the nucleus agent pore former closed spherical pores

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Pavlenko A. , Cheylitko A. , Koshlak H. , Piotrowski J. Z.

Journal of New Technologies in Environmental Science

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2017

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tom Vol. 1, nr 3

101--107

EN

Many experimental data indicate a relationship between the porosity of the material and its thermophysical properties [1-3]. Influence of porosity on the thermal conductivity of the material can be considered following the example of experimental data [2]. The values of thermal conductivity coefficient of iron (58.19 W/(m∙K)) and a rock formation (3.26 W/(m∙K)) differ by almost 18 times, but the filling of iron balls and balls rock formation of the same a porosity of 62.5% has nearly the same coefficient of thermal conductivity (0.0403 W/(m∙K) and 0.0402 W/(m∙K) respectively). However, the way of forming the porous structure has not yet been investigated, and a clear relationship between the porosity and the physical properties of the material not found.

9

Constitutive Relations in the Process of Hot Wood Rolling

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Malujda I. , Mielniczuk J.

Machine Dynamics Problems

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2004

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tom Vol. 28, No. 4

35-40

EN

While process modelling of plasticization of wood layer the factor of principal importance is the critical effort of material when its plastic flow occurs. The value of this stress depends on the thermomechanical properties of the material and, in particular, on three parameters of the process: roller temperature, strength and duration of the force exerted on the surface of the plasticized material. This paper attempts to formulate constitutive equations of the yield condition of porous and anisotropic medium taking into account the influence of temperature. This problem is analysed on the basis of plasticization of a thin layer of wood during hot rolling.

10

The Application of Friction Stir Processing to the Fabrication of Magnesium-Based Foams

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Azizieh M. , Pourmansouri R. , Balak Z. , Kafashan H. , Mazaheri M. , Kim H. S.

Archives of Metallurgy and Materials

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2017

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tom Vol. 62, iss. 4

1957--1962

EN

In the present paper, friction stir processing (FSP) is used to fabricate magnesium-based nanocomposite foams. The effects of the number of FSP passes, TiH2 to Al2O3 weight ratio, and foaming temperature; on the pore distribution and porosity are described. The results indicate that a minimum TiH2 to Al2O3 weight ratio is necessary to provide the best pore distribution and porosity. Closed-cell porous magnesium with a porosity of about 17.5% was successfully fabricated using 4-pass FSP at 800 rpm, by adding 5 mass% TiH2 and 3.5 mass% Al2O3; at a holding temperature of 858 K, and a holding time of 45 min.

11

Determining rock pore space using image processing methods

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Mazurkiewicz Ł. , Młynarczuk M.

Geology, Geophysics and Environment

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2013

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tom Vol. 39, no. 1

45--54

EN

This paper presents the possibilities of using image processing for determining effective porosity in carbonate and terrigenous rocks. For the purpose of the research, an algorithm was created, which automatically determines the percentage of pore space, based on the analysis of video sequences registered with the use of a microscope. Up to this point stereological research used for describing rock porosity was conducted manually, which is both troublesome and time consuming. The proposed algorithm uses a series of transformation operations such as: non-context operations, contextual operations and morphological transformations. The presented algorithm was tested on video sequences of thin sections of carbonates from Buszewo and Kościan, and sandstones from Dobrzyca and Solec. The obtained results show, that the method of automatic video sequence analysis used for detection and measurement of porosity leads to satisfying results.

12

Are community composition and abundance of psammon Rotifera related to grain-size structure of beach sand in lakes?

100%

Ejsmont-Karabin J.

Polish Journal of Ecology

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2004

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tom Vol. 52, nr 3

363-368

EN

The aim of the study was top test the hypothesis that the size distribution of sand grains in lake beach should affect the species composition, densities and body-size structure of psammon communities of Rotifera. Studies were carried out in hydro-, hydro- and euarenal zones of 38 beaches (5 to 50 m long and 1 to 10 m wide) in 16 lakes of different trophic status and morphometry (Masurian Lakeland, Poland). Porosity has no impact on psammon rotifer numbers as well as body-size of animals does not seem to play a significant role in species preference to different size classes of sand grains. However, the significant correlations were found between the rotifer numbers and the share of grain size fraction 0.25 - 1.00 mm (positive) and the share of the largest (i.e. > 1 mm) fraction (negative). The psammobionts generally are more related to the grain size ffraction 0.5-1.0 mm than the psammoxenes and psammophiles. Although particular rotifer species prefer different grain size fractions, bdelloids arre the only grroup of Rotifera preferring the smallest (<0.125 mm) grain fraction.

13

Preparation and properties of porous carbon material containing magnesium oxide

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Przepiórski J. , Czyżewski A. , Kapica J. , de la Casa-Lillo M.

Polish Journal of Chemical Technology

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2011

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tom 13

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nr 4

42-46

EN

Porous carbons loaded with magnesium oxide were prepared through one-step process. Poly(ethylene terephthalate) and natural magnesite were used as carbon source and MgO precursor, respectively. An impact of a temperature and relative amounts of raw components used for preparations on the textural parameters of resulting hybrid materials is presented and discussed. As found, pore structure parameters tend to decrease along with MgO loading and temperature used during preparation process. Micropore area is the parameter being reduced primarily.

14

Petro-physical properties of geological formation in the aspect of possible CO2 sequestration

100%

Klempa M. , Porzer M. , Bujok P. , Pavlus J. , Rado R.

AGH Drilling, Oil, Gas

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2013

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tom Vol. 30, no. 1

109--116

EN

CO2 emissions and a future increasing trend can be, by some scientists, considered a serious menace for the sustainable development of mankind and the reduction is necessary for the environment protection. Carbon dioxide is one of the most important gases that causes greenhouse effect, which warms up the earth surface as a consequence of a different heat flow between the earth and the atmosphere.

15

The analysis of the relations between porosity and tortuosity in granular beds

100%

Sobieski W. , Lipiński S.

Technical Sciences / University of Warmia and Mazury in Olsztyn

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2017

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tom nr 20(1)

75--85

EN

In the paper, functions describing different porosity-tortuosity relations were collected, and then the tortuosity values were calculated for a one granular bed consisting of spherical particles with normal distribution of diameters. Information about the bed porosity and particle sizes was obtained from measurements conducted for an artificial granular bed, consisting of glass marbles. The results of calculations were compared with the results of two other methods of tortuosity determination, performed for the same case (details are not described in this paper): the first of them uses the Path Tracking Method, the second one - information about the velocity components in a creeping flow (the Lattice-Boltzmann Method was applied to obtain the velocity field in the flow). The main aim of our article was to test whether the functions linking tortuosity with porosity, which are available in the literature, give similar results as the methods described above. To achieve this aim, the relative errors between results of calculations for the collected formulas and values from the both previous mentioned methods were calculated.

16

The sorption of SO2 on the peat from different depths.

100%

Jańczak C. , Jankowska A. , Grigorieva E. N. , Choffe K.

Prace Naukowe Instytutu Chemii i Technologii Nafty i Węgla Politechniki Wrocławskiej. Konferencje

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2002

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tom Vol. 10, nr 57

485-490

EN

The determination of the sorption properties of peat from different depths was done. The research was carried out on the intermediate littoral peats near the Baltic Sea from the layers situated at every 0.5 m at depths up to 3 m . The effectiveness of peat sorbents has been detd. based on the isotherms of SO2, benzene, and CO2 sorption. This was done using the gravimetric method. The interpretation of the benzene sorption isotherms was carried out on the basis of the theory of volumetric filling of pores. These results were compared with respectively investigations on samples of steam-activated carbons (based on hard coal and wood tar) and demineralized brown coal.

17

Different methods for shale volume determination

100%

Wandycz P.

Geology, Geophysics and Environment

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2014

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tom Vol. 40, no. 1

140

EN

One of the most important steps in well log analysis is proper evaluation of shaly formations. Clay minerals may cause a lot of problems with calculating porosity or water saturation (Jarzyna 1997). There are several different methods that allow us to determine the volume of shale in the geological formation. It is a fact that choosing correct technique is often a problem which many well log analysts must struggle with (Bassiouni 1994). This paper shows the results that interpreter might obtain using different types of methods for quantitative determination of shale content. Well logs used for the calculation of the shale volume come from Borehole A-1, which is located in west central Poland in Greater Poland Voivodeship. The first method for the determination of the shale volume was the Gamma Ray technique. This method allowed to calculate the amount of shale using only one log as an input (Ellis & Singer 2008). Both nonlinear and linear equations were applied to calculate the volume of shale. The second technique used is the Neutron-Density Method (Techlog Manual 2011), where two logs were used as an input data source, Neutron Porosity log (NPHI) and Bulk Density (RHOB). The third and the last method for calculating the volume of shale in Borehole A-1 was Resistivity technique, with deep resistivity log (Schlumberger 1998). The results obtained with each technique were compared to each other and then combined together. The last step allowed to calculate the final volume of shale (Schlumberger 1998). Since each technique gave different results, and it was impossible to choose the correct one, the combination of methods had to be applied for the calculation of shale volume. The errors for every method have a tendency to increase, not to reduce, the apparent shale volume (Schlumberger 1998), therefore a "minimum combination" was applied, meaning that the minimum values of all the variables (calculated shale volumes) were used as an input. Results of the "minimum combination" method give the most probable information about the volume of the shales within the analyzed geological formation.

18

A new approach to define surface/sub-surface transition in gravel beds

100%

Haynes H. , Ockelford A.-M. , Vignaga E. , Holmes W.

Acta Geophysica

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2012

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tom Vol. 60, no. 6

1589-1606

EN

The vertical structure of river beds varies temporally and spatially in response to hydraulic regime, sediment mobility, grain size distribution and faunal interaction. Implicit are changes to the active layer depth and bed porosity, both critical in describing processes such as armour layer development, surface-subsurface exchange processes and siltation/sealing. Whilst measurements of the bed surface are increasingly informed by quantitative and spatial measurement techniques (e.g., laser displacement scanning), material opacity has precluded the full 3D bed structure analysis required to accurately define the surface-subsurface transition. To overcome this problem, this paper provides magnetic resonance imaging (MRI) data of vertical bed porosity profiles. Uniform and bimodal (σg = 2.1) sand-gravel beds are considered following restructuring under sub-threshold flow durations of 60 and 960 minutes. MRI data are compared to traditional 2.5D laser displacement scans and six robust definitions of the surface-subsurface transition are provided; these form the focus of discussion.

19

Numerical Generation of a Fixed Bed Structure

100%

Marek M.

Chemical and Process Engineering

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2013

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tom 34

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nr 3

347-359

EN

A numerical algorithm is presented for the filling process of a cylindrical column with equilateral cylinders. The process is based on simplified mechanics - the elements are added one by one until the mechanical equilibrium is reached. The final structure is examined with respect to the global and local porosity distribution. Oscillating radial porosity profile is obtained in accordance with experimental data.

20

Diagenetic impact on reservoir quality in deeply buried tight Rotliegend Sandstones - case study of Polish Permian Basin

100%

Nosal J.

Geology, Geophysics and Environment

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2014

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tom Vol. 40, no. 1

156--157

EN

During burial, sediments and rocks undergo physical and chemical changes due to temperature and pressure growth. All these processes are known as diagenesis (Boggs 2009). These changes play an important role in postedpositional modification of reservoir parameters, such as porosity, permeability and filtration. Primary porosity of rock may be reduced by cement precipitation, mechanical compaction, mineral reactions or pressure solutions, and moreover increased (secondary porosity) during burial, as a result of grain and cement dissolutions, mineral reactions or fracturing (Bjorlykke 1983). Permeability is controlled mainly by pore-throat size (Pittman 1992) and its loss corresponds to the decreasing volume of primary porosity (Pittman 1992, Dutton & Loucks 2010). The aim of presented work was investigation of diagenetic changes within deeply buried tight Rotliegend Sandstones from Polish part of Southern Permian Basin and their impact on reservoir properties of rocks. For the research were selected 26 core samples from 16 wells and depth interval 3439.8-4284.7 m. All wells are located within the aeolian sediments of Eastern Erg (central part of Polish part of Permian Basin). Samples are represented by medium - and fine - grained quartz arenites and wackes. Qualitative examination of samples included petrographic analysis of thin sections in polarizing microscope in transmitted light and scanning electron microscopy. Numerical characterization of pore space was obtained during petrophysical analysis on 11 samples, usingmercury porosimetry. Diagenetic processes strongly amended reservoir parameters of rocks. The greatest impact on the decrease of primary porosity had mechanical compaction. It resulted in the development of long grain contacts. As the main cement component were identified clays, with subordination of carbonate, ferruginous and anhydrite minerals. Porosity of analyzed samples does not exceeded 6%, permeability - 0.1 mD. Reservoir properties of Rotliegend Sandstones were affected by diagenesis, forced by temperature and pressure growth during burial. Primary porosity of sandstones was decreased by mechanical compaction and cement precipitation. Observed evidence of secondary porosity was created due to dissolution of less stable minerals - feldspars. Precipitation of authigenic clay minerals also highly reduced permeability and filtration of sandstones.