Wyniki wyszukiwania - Biblioteka Nauki

1

Dynamika płynu w przepuszczalnym ośrodku porowatym o anizotropowej strukturze przestrzeni porów

100%

Cieszko M.

|

tom Z. 53(241)

43-55

PL

Przedmiotem pracy jest modelowanie ruchu płynu w anizotropowej przestrzeni porów nieodkształcalnego szkieletu. Rozważania oparto na nowym makroskopowym modelu nasyconego płynem porowatego ośrodka [3, 4], w którym przepływ płyn u przez szkielet o anizotropowej strukturze przestrzeni porów jest opisywany jako ruch kontinuum materialnego w płaskiej anizotropowej przestrzeni metrycznej (przestrzeni Minkowskiego) zanurzonej w przestrzeni Euklidesa będącej modelem przestrzeni fizycznej. Sformułowano równania bilansu masy i pędu płynu oraz wyprowadzono równania falowe dla zaburzeń o malej amplitudzie w barotropowym nielepkim płynie wypełniającym anizotropową przestrzeń porów. Pokazano, że prędkość płaskich fal w takim ośrodku zależy od kierunku ich propagacji i dla kierunków głównych przestrzeni porów jest odwrotnie proporcjonalna do krętości porów.

EN

The paper describes fluid motion in a rigid porous medium of anisotropic pore space structure. The discussion was based on the new macroscopic model of saturated porous medium (Cieszko [3], [4]) in which fluid flow through porous skeleton of anisotropic pore structure is described as a motion of the material continuum in the plane anisotropic metric space (Minkowski space) immersed in the Euclidean one that is the model of the physical space. The mass and linear momentum balance equations for fluid were derived and the equation for wave propagation in barotropic inviscid fluid filling anisotropic space of pores was obtained. It was shown that the velocity of the plane wave in such a medium depends on the direction of wave propagation and for the principal direction of the pore space is invesely proportional to the tortuosity of pores.

2

Multi parameter logging evaluation of tight sandstone reservoir based on petrophysical experiment

100%

Li H. , Deng S. , Xu F. , Niu Y. , Hu X.

|

tom Vol. 69, no. 2

429--440

EN

Acoustic, resistivity and nuclear magnetic resonance (NMR) logging are important means of reservoir evaluation. In this paper, the information of pore structure, such as the aspect ratio and the shape, is obtained by rock physical experiments like constant velocity mercury injection and casting thin section. Taking pore structure information as a link, the theoretical relations among acoustic-NMR, acoustic-resistivity and resistivity-NMR of rocks are studied, respectively, based on the diferential equivalent model and fractal theory, and the theoretical derivation results are verifed by AE acoustic emission experiment, rock resistivity experiment and NMR experiment. It is found that there is a power function relationship between the P/S wave velocity and the geometric mean value of NMR T2. Moreover, there are also power function relationships between the slowness of P/S wave and resistivity, and between the value of NMR T2 and the increase rate of resistance. Based on the above relationship, the gas reservoir can be identifed by acoustic-resistivity-NMR multi-parameters in well G of the study area. Compared with the conventional P/S velocity ratio and P-wave slowness intersection method, the separa tion efect of gas and water is more obvious.

3

Zastosowanie przestrzeni Minkowskiego do modelowania anizotropowej przestrzeni porów przepuszczalnych materiałów porowatych

100%

Cieszko M.

|

tom Z. 47 (228)

81-90

PL

Przedmiotem pracy jest modelowanie anizotropowej struktury porów przepuszczalnych materiałów porowatych. W pracy zaproponowano nowy makroskopowy model takiego ośrodka, w którym anizotropowa przestrzeń porów przepuszczalnego szkieletu rozważana jest jako anizotropowa, metryczna przestrzeń Minkowskiego zanurzona w przestrzeni Euklidesa będącej modelem przestrzeni fizycznej. W pracy wykorzystano metryki obu przestrzeni, aby zdefiniować podwójne miary elementów linii, powierzchni i objętości. Umożliwiło to wprowadzenie czysto geometrycznych definicji parametrów charakteryzujących anizotropową strukturę porów materiałów porowatych: porowatości objętościowej, krętości porów oraz porowatości powierzchniowej. Pokazano, że izotropowa struktura porów jest charakteryzowana jedynie przez dwa niezależne parametry.

EN

The present paper describes the anisotropic pore structure of permeable porous materials. A new macroscopic model of saturated porous medium is proposed in which a fluid flow through porous skeleton of anisotropic pore structure is considered as a motion of the material continuum in the plane anisotropic metric space (Minkowski space) immersed in Euclidean space. The metrics of both spaces is used to determine the double measures of any line, surface and volume elements. All that made it possible to introduce pure geometrical macroparameters typical for anisotropic pore structure of porous materials, namely: tortuosity, volume and surface porosity. It has been shown that the isotropic pore structure is described only by two independent parameters.

4

Changes in fractal dimension and durability of ultra‑high performance concrete (UHPC) with silica fume content

100%

Luan C. , Wang J. , Gao J. , Wang J. , Du P. , Zhou Z. , Huang Y. , Du S.

|

2022

|

tom Vol. 22, no. 3

art. no. e123

EN

The combined utilization of silica fume (SF) and steel fiber in UHPC is an inevitable trend to improve its mechanical properties and durability. In this study, the influence of SF dosage on mechanical property, permeability, drying shrinkage as well as the pore structure and fractal dimension (Ds) of UHPC was investigated. Finally, the relationships between the durability of UHPC and the porosity as well as the Ds were revealed and discussed. The results demonstrate that the synergistic effect of SF and fiber increased mechanical properties of UHPC due to the friction and mechanical interlocking of the steel fiber to the fiber-matrix and the adhesion between fiber and paste provided by the silica fume. In addition, incorporating 20% enhanced the mechanical property, decreased the chloride diffusion coefficient, and increased the Ds value. Moreover, increasing Ds value linearly raised compressive strength and drying shrinkage but nonlinearly depressed permeability in UHPC, so Ds can be served as a navel parameter to characterize the permeability and drying shrinkage of UHPC.

5

Prediction of porosity and gas saturation for deep‑buried sandstone reservoirs from seismic data using an improved rock‑physics model

84%

Yaneng L. , Handong H. , Morten J. , Yadi Y. , Jinwei Z. , Yanjie C.

|

tom Vol. 67, no. 2

557--575

EN

In recent years, many important discoveries have been made in global deep oil and gas exploration, which indicates that deep exploration has gradually become one of the most important areas in current and future hydrocarbon exploration. However, the prediction of deep reservoirs is very challenging due to their low porosity and complex pore structure characteristics caused by the burial depth and diagenesis. Rock physics provides a link between the geologic reservoir parameters and seismic elastic properties and has evolved to become a key tool of quantitative seismic interpretation. Based on the mineral component and pore structure analysis of studied rocks, we propose an improved rock-physics model by introducing a third feldspar-related pore for deep-buried sandstone reservoirs to the traditional Xu–White model. This modelling process consists of three steps: first, rock matrix modelling using time-average equations; second, dry rock modelling using a multipore analytical approximation; and third, fluid-saturated rock modelling using a patchy distribution. It has been used in total porosity estimation, S-wave velocity prediction and rock-physics template establishment. The applicability of the improved rock-physics model is verified by a theoretical quartz-water model test and a real data total porosity estimation compared with the traditional Xu–White model and the density method. Then, a rock-physics template is generated by the improved rock-physics model for porosity and gas saturation prediction using seismic data. This template is carefully calibrated and validated by well-log data at both the well-log scale and seismic scale. Finally, the feasibility of the established rock-physics template for porosity and gas saturation prediction is validated by a deep-buried sandstone reservoir application in the East China Sea.

6

Influence of grain size and gas pressure on diffusion kinetics and CH 4 sorption isotherm on coal

84%

Kozieł K. , Gajda A. , Skiba M. , Skoczylas N. , Pajdak A.

|

tom Vol. 68, no. 1

3--23

EN

The article presents a methodology for predicting the impact of the longwall shearer’s control parameter on methane emission rate to the working of a longwall based on computational fluid dynamics (CFD) methods. The methodology was applied to the Z-11a longwall panel conditions at the Jankowice Hard Coal Mine. The results of the methane emissions rate in the working of a longwall for three variations of the position of the longwall shearer are shown and discussed. The modelled issue’s geometry, numerical grid, assumptions, and boundary conditions are presented. The filtration parameters of goafs are discussed. Relationships to estimate the various sources of methane emissions into the air flowing around the longwall panel Z-11a are presented. The results of the model tests were compared with the mining data in the Z-11a longwall panel at the Jankowice Hard Coal Mine.

7

The effect of ozonation on sorption properties of active carbon and its porous structure. Model investigations

84%

Wolborska A. , Maryniak K. , Perkowski J.

Polish Journal of Chemical Technology

|

2002

|

tom Vol. 4, nr 2

42-46

EN

The ozone-granulated active carbon system (ozone-GAC) is more often introduced in the technological water treatment cycle. The reactivity of ozone towards water pollutants leads to their oxidation and growth of biodegradability, which is well-known and favourable for the operation of a carbon bed. Does ozonation also affect the active carbon itself? Preliminary investigations on the ozonation of water solution of active carbon are presented. The results of the process were determined by analysing the porous structure of initial adsorbents and after their modification. Also the changes in their sorptivity were determined by studies of adsorption equilibrium for model systems of phenol-active carbon. In the investigations carbon types NOR1T ROW 0.8 SUPRA and PK 1-3 were used. The modification of initial adsorbents deteriorated to a small extent the parameters of porous structure such as specific surface, total pore volume and fraction of micropores. As a result of the ozonation, the sorptivity of the tested active carbon to phenol changes. In general, this change does not refer to the monolayer volume. A tendency to weaken the adsorbate-adsorbent relation is observed.

8

Petrophysical properties prediction of deep dolomite reservoir considering pore structure

84%

Gui J. , Yin X. , Jianhu G. , Li S. , Liu B.

Acta Geophysica

|

2022

|

tom Vol. 70, no 4

1507--1518

EN

Prediction of petrophysical properties of deep dolomite reservoir using elastic parameter data is challenging and of great uncertainty. Changes in the petrophysical properties generally induce perturbations in elastic properties. Rock-physics model, which plays a role as a bridge between petrophysical properties and elastic properties, determines the accuracy of inversion for petrophysical properties using elastic properties. Different pore structures lead to variations of rock-physics relationships, and in dolomite reservoir, the influence of pore structure on elastic properties is larger than that of petrophysical properties. We first propose a statistical rock-physics model, in which we consider the effect of pore structure on the nonlinear rockphysical relationship between petrophysical properties and elastic properties of dolomite reservoirs. Then, we propose a Bayesian inversion approach of using elastic properties to predict petrophysical properties and use weight factors to address the difference in accuracy of the input elastic properties in the Bayesian inversion framework. Examples illustrate the proposed approach may produce petrophysical properties of high accuracy for deep dolomite reservoirs.

9

Effects of early‑age temperature and salt ion corrosion on the macroproperty deterioration of concrete and corresponding micromechanism

84%

Xue W. , Fan H. , Liu X. , Shen L.

|

2022

|

tom Vol. 22, no. 2

art. no. e98, 1--16

EN

This paper experimentally examines variations in the macroscopic properties of concrete under the interaction of early-age temperature and salt ion corrosion and investigates the microscopic mechanism of these variations from the perspective of pore structure and microcracks. The results show a prominent initial defect compaction stage of the compressive stress-strain curves of the specimens under the interaction of two factors, an increase in the number of pores and a high degree of crack development. Accordingly, the peak strength, secant elastic modulus and porosity of the specimens are greatly affected by the interaction between early-age temperature and salt ion corrosion, as reflected by the obvious deterioration trend. Based on a theoretical analysis, the concept of the initial defect strain ratio is proposed, the relationship between the total deformation and two indicators (initial defect deformation and matrix deformation) is clarified, and a constitutive model that reflects the initial defect compaction characteristics is established.