Porosity Measurement Methods Research Articles

Assessing flow diverter porosity: a comparative analysis of quantification techniques based on imaging and simulation

ABSTRACT Background/Purpose Flow diverter porosity directly influences the blood flow reduction at the aneurysm neck level and the anatomical result of the treatment. In this research, we present and compare three methodologies to determine the local porosity of deployed flow diverters. Method Three-dimensional rotational angiography was used to obtain computational vessel models of three patients. Different flow diverters were virtually deployed in the computational models and implanted in 3D-printed models of the vasculatures by interventional neuroradiologists. Experimental porosity determinations were conducted using 2D microscope photographs and 3D Dyna-CT images (i.e. cone-beam Computed Tomography angiographic images), while simulated porosity was computed using ANKYRAS software. Results No statistically significant differences were observed between the porosity distributions from the three methods (p > 0.01). When computing the differences point-by-point, narrow distributions centered on zero were obtained, revealing a good agreement in the determinations. Orthogonal regression analysis affirmed this equivalence. The lowest agreement between porosity measurement methods was observed to occur at curve segments with relatively low porosity. Conclusions The local porosity of deployed flow diverters can be accurately determined by the three methods presented in this work. Assessing FD porosity with 3D Dyna-CT images would allow the evaluation of real patient data, whereas simulations could determine local porosity before the treatment.

Research on porosity characterization methods of shale oil reservoirs in Lianggaoshan Formation, Sichuan Basin

Shale oil, an important component of unconventional oil and gas resources, mainly exists in the storage spaces such as shale pores, microfractures, etc. Porosity is commonly used to quantitatively describe the storage space of shale oil and is a key parameter in reservoir evaluation. However, there are significant differences in the results by existing experimental methods for porosity measurement, and moreover, it is difficult to compare the porosity obtained by the experimental measurement method with the logging calculation method. It is urgent to explore reasons for the differences in porosity measurement between various porosity experiments and logging calculations of the shale oil reservoir, and propose an effective method for shale oil reservoir to characterize porosity. In this research, core samples of shale oil reservoirs from the Lianggaoshan Formation of the Sichuan Basin were selected to measure the porosity by means of experimental methods including helium gas charging, saturation liquid method, nuclear magnetic resonance (NMR), etc. Meanwhile, porosity was calculated using the combination method of lithology scanning (LS) logging and conventional logging as well as the NMR logging method. Subsequently, porosity experimental results and logging calculation results were compared to clarify the applicability of various porosity characterization methods. The research results indicate that: 1) The porosity measurement results by the saturation liquid method and the NMR experimental method are close, both greater than that using the helium gas charging method; 2) The hydrogen signal of the dry-state sample is significant in the NMR experiment, mainly originating from organic matter and clay minerals; 3) The NMR short relaxation component in the water-saturated state primarily reflects the signal of organic matter and clay mineral matrix, while the long relaxation component reflects the pore fluid component; 4) After deducting the NMR signal of the dry-state core, the core NMR porosity measurement results under the water-saturated state agree well with that using the saturation liquid method, which is an indicative of effective reservoir porosity; 5) The NMR logging is limited by its echo spacing and cannot reflect the signal from organic matter and the crystal water in clay minerals at T2 < 0.3 ms. Taken together, the porosity measurement method of subtracting the dry-state NMR signal from the water-saturated state NMR signal is considered effective and can be used to reflect the porosity of shale oil reservoirs in the Lianggaoshan Formation of the Sichuan Basin.

Parameter development for Laser Powder Bed Fusion of nickel-based Haynes 282 using diverse density determination methods

To manufacture functional components using laser powder bed fusion (PBF-LB/M), the execution of a parameter development with the specific material and machine is an indispensable step. Typically, in the search for the optimal parameter set, the volumetric energy density (VED) used to melt the material serves as an adjustment variable, while the resulting part density as the target parameter. Although this approach effectively reduces the process parameters search-space, additional criteria concerning part quality should be considered in the development. This paper introduces a systematic parameter selection approach, refining the characterization process for processing the nickel-based superalloy Haynes® 282®. The presented strategy not only incorporates the density as target condition but also considers the surface quality and dimensional accuracy of the manufactured samples, crucial for near-net-shape manufacturing. Additionally, three porosity measurement methods (Archimedes method, microscopy, gaspycnometry) for AM metal parts are compared, and their validity for this purpose is discussed.

A new neutron-gamma porosity measurement method for pulsed neutron logging tools

As an alternative method for the compensated neutron porosity measurement method, the neutron-gamma porosity measurement method is widely used in cased holes. However, the neutron-gamma porosity measurement method has some problems, such as the lack of detailed theoretical analysis and low sensitivity in high-porosity formations. The purpose of this paper is to clarify the theory of neutron-gamma porosity measurement, improve the measurement sensitivity, and eliminate the effects of environmental factors. Based on the neutron diffusion theory and the gamma transport theory, the distribution of capture gamma rays is described. A new neutron-gamma porosity measurement method is developed based on inelastic and capture gamma-ray distribution. The applicability of the new method in different environments is analyzed using the Monte Carlo method, and the effectiveness of this method is verified using the synthetic model. The results indicate that the capture gamma-ray ratio is only related to the source-detector distance, gamma-ray attenuation length, and neutron migration length. By combining density, different neutron cross sections, inelastic gamma-ray count ratio, and capture gamma-ray count ratio, the parameter secondary gamma-ray hydrogen index (SGH) related to hydrogen index can be extracted. The dynamic range of SGH is much higher than thermal neutron count ratio and the capture gamma-ray count ratio. The errors in porosity calculation by this method under different borehole and lithologic conditions are generally less than 2 pu. The calculation error of this method is close to that of the compensated neutron porosity measurement method. In addition, the applicability of the new method is analyzed without density data, and the results indicate that the calculation results are basically consistent with the results of calculation with density data. The new method has great potential for extensive applications in cased holes or open holes as an alternative for the compensated neutron porosity logging measurement method.

“Rigid-elastic chimera” pore skeleton model and overpressure porosity measurement method for shale: A case study of the deep overpressure siliceous shale of Silurian Longmaxi Formation in southern Sichuan Basin, SW China

Based on analysis of pore features and pore skeleton composition of shale, a “rigid elastic chimeric” pore skeleton model of shale gas reservoir was built. Pore deformation mechanisms leading to increase of shale porosity due to the pore skeleton deformation under overpressure were sorted out through analysis of stress on the shale pore and skeleton. After reviewing the difficulties and defects of existent porosity measurement methods, a dynamic deformed porosity measurement method was worked out and used to measure the porosity of overpressure Silurian Longmaxi Formation shale under real formation conditions in southern Sichuan Basin. The results show: (1) The shale reservoir is a mixture of inorganic rock particles and organic matter, which contains inorganic pores supported by rigid skeleton particles and organic pores supported by elastic-plastic particles, and thus has a special “rigid elastic chimeric” pore structure. (2) Under the action of formation overpressure, the inorganic pores have tiny changes that can be assumed that they don't change in porosity, while the organic pores may have large deformation due to skeleton compression, leading to the increase of radius, connectivity and ultimately porosity of these pores. (3) The “dynamic” deformation porosity measurement method combining high injection pressure helium porosity measurement and kerosene porosity measurement method under ultra-high variable pressure can accurately measure porosity of unconnected micro-pores under normal pressure conditions, and also the porosity increment caused by plastic skeleton compression deformation. (4) The pore deformation mechanism of shale may result in the “abnormal” phenomenon that the shale under formation conditions has higher porosity than that under normal pressure, so the overpressure shale reservoir is not necessarily “ultra-low in porosity”, and can have porosity over 10%. Application of this method in Well L210 in southern Sichuan has confirmed its practicality and reliability.

Recent Progress in Single and Combined Porosity-Evaluation Techniques for Porous Materials.

The accurate determination of the porosity and specific surface area of porous materials such as shale and cement plays a key role in gas-energy-storage estimation and exploitation, building-heat and humidity-transfer investigation, and permeability-characteristics evaluation. Therefore, it is crucial to select appropriate measurement methods to accurately study the porosity, as well as other properties, of porous materials. In this review, various porosity-measurement methods are discussed. The most recent research findings and progress in combined methodologies are introduced and summarized. The measurement medium and chemical composition of the sample affect the porosity-measurement results. Therefore, depending on the measurement properties of different methods and the characteristics of the sample, an appropriate method can be selected. Furthermore, various methods can be combined to obtain more accurate measurement results than individual methods.

Imbibition of Newtonian Fluids in Paper-like Materials with the Infinitesimal Control Volume Method

Paper-based microfluidic devices are widely used in point-of-care testing applications. Imbibition study of paper porous media is important for fluid controlling, and then significant to the applications of paper-based microfluidic devices. Here we propose an analytical approach based on the infinitesimal control volume method to study the imbibition of Newtonian fluids in commonly used paper-like materials. Three common paper shapes (rectangular paper strips, fan-shaped and circular paper sheets) are investigated with three modeling methods (corresponding to equivalent tiny pores with circle, square and regular triangle cross section respectively). A model is derived for liquid imbibition in rectangular paper strips, and the control equations for liquid imbibition in fan-shaped and circular paper sheets are also derived. The model is verified by imbibition experiments done using the mixed cellulose ester filter paper and pure water. The relation of imbibition distance and time is similar to that of the Lucas−Washburn (L−W) model. In addition, a new porosity measurement method based on the imbibition in circular paper sheets is proposed and verified. Finally, the flow rates are investigated. This study can provide guidance for the design of different shapes of paper, and for better applications of paper-based microfluidic devices.

Terahertz-Based Porosity Measurement of Pharmaceutical Tablets: a Tutorial

Porosity, one of the important quality attributes of pharmaceutical tablets, directly affects the mechanical properties, the mass transport and hence tablet disintegration, dissolution and ultimately the bioavailability of an orally administered drug. The ability to accurately and quickly monitor the porosity of tablets during manufacture or during the manufacturing process will enable a greater assurance of product quality. This tutorial systematically outlines the steps involved in the terahertz-based measurement method that can be used to quantify the porosity of a tablet within seconds in a non-destructive and non-invasive manner. The terahertz-based porosity measurement can be performed using one of the three main methods, which are (i) the zero-porosity approximation (ZPA); (ii) the traditional Bruggeman effective medium approximation (TB-EMA); and (iii) the anisotropic Bruggeman effective medium approximation (AB-EMA). By using a set of batches of flat-faced and biconvex tablets as a case study, the three main methods are compared and contrasted. Overall, frequency-domain signal processing coupled with the AB-EMA method was found to be most suitable approach in terms of accuracy and robustness when predicting the porosity of tablets over a range of complexities and geometries. This tutorial aims to concisely outline all the necessary steps, precautions and unique advantages associated with the terahertz-based porosity measurement method.

Porosity measurement of heavy oil sands

ABSTRACTPorosity measurement is an important step for petrophysical characterization of reservoir rocks, as porosity is essential for analysing elastic properties and estimating the capacity of rocks to hold hydrocarbon resources. Commonly used porosity measurement methods fail to work on heavy oil sands, because of the loose fragile sand frame and solid‐like irreducible heavy oil. We develop three methods to measure the porosity of heavy oil sands, which are feasible and affordable in most laboratories. Method 1 involves calculating the bulk volume of the sample by measuring its physical dimensions directly. Method 2 uses calibrated sample weight and volume (after removing the protecting foil cover and metal clips). Method 3 first applies pressurizing on samples and then measures the weight and volume of the bare samples. The measurement results of the three methods are then compared and method 3 is determined as the most reliable, which is also verified by the porosity log. Finally, an analysis of the potential sources of errors associated with method 3 is performed.

A robust NMR method to measure porosity of low porosity rocks

Rocks in low porosity reservoirs contain a considerable number of micro-pores which make the accurate measurement of total porosity more and more difficult. Nuclear magnetic resonance (NMR) is wildly used in petrophysical analyses; however, when using traditional NMR porosity measurement method, it is hard to detect signals of micro-pores due to the limitation of echo spacing. In the current research study, we used a robust NMR method, i.e. magic-sandwich echo (MSE) pulse sequence, to measure the porosities of various types of hydrocarbon-bearing rocks, and compared the results with those of the conventional measurement methods. It is worth mentioning that clay minerals have a great influence on NMR porosity measurement results. Therefore, it was needed to measure the magnetic resonance signal of dry rock to reduce the influences of clay minerals on the rock porosity measurement by NMR approach. After conducting experiments on different low porosity rocks, the results showed that the relative error of our method was 13.50%, which was more accurate than traditional NMR porosity measurement method. In addition, based on porosity deviations of shales and homonuclear dipolar coupling, we put forward a novel method to estimate shale total organic carbon (TOC) content which is a helpful tool for evaluation of unconventional shale reservoirs.

Development of Porosity Measurement Method in Shale Gas Reservoir Rock

The pore scales have impacts on transport mechanisms in shale gas reservoirs. In this research, digital helium porosity meter is used for porosity measurement by considering real condition. Accordingly it is necessary to obtain a good approximation for gas filled porosity. Shale has the typical effective porosity that is changing as a function of time. Effective porosity values for three different shale rocks are analyzed by this proposed measurement. We develop the new measurement method for characterizing porosity phenomena in shale gas as a time function by measuring porosity in a range of minutes using digital helium porosity meter. The porosity of shale rock measured in this experiment are free gas and adsorbed gas porosoty. The pressure change in time shows that porosity of shale contains at least two type porosities: macro scale porosity (fracture porosity) and fine scale porosity (nano scale porosity). We present the estimation of effective porosity values by considering Boyle-Gay Lussaac approximation and Van der Waals approximation.

Porosity Measurement method of Al2O3 Sprayed Coating Using Precipitaion Reaction of Electroplating Metal

Porosity Measurement method of Al<SUB>2</SUB>O<SUB>3</SUB> Sprayed Coating Using Precipitaion Reaction of Electroplating Metal

Development and optimization of porosity measurement techniques

Different porosity measurement methods are investigated and compared to ascertain a relatively accurate and efficient method suitable for laboratory utilization. As model material Sr0.895Y0.07TiO3−δ (SYT) ceramic material, which is designed as anode substrate for planar solid oxide fuel cells, is studied. Seven batches with different porosity are investigated using image analysis method and Archimedean porosimetry, operating under different conditions, and compare with the results from mercury porosimetry. The experimental results reveal for these methods different accuracies of the true porosity for different porosity ranges.

Development of Porosity Measurement Method Based on Modern Microscopic Techniques

The aim of the research, presented in the paper, is to show and to assess the porosity structure in accordance to the dimensions of carbon dioxide particle. The characteristic surface morphology of the sample and the visualisation of the coal porous structure have been obtained using the atomic force microscope (AFM). The presented study of the coal microstructure is a part of the concepts of the project which aim is to develop the guidelines for design of the innovative technology of shale gas recovery with the use of liquid CO2. The technology will be based on Military University of Technology invention which considers gaseous hydrocarbons recovery from at least two levels of lateral wellbores with the use of supercritical CO2, what will result with wellbore productivity increase, because CO2 will cause desorption of CH4 from the porous structure of shale rock and the thermodynamic transformation of CO2 in the reservoir will help the rock fracturing. The heat energy added for the fracturing process will be taken from the surrounding rock mass.

Evaluation of a porosity measurement method for wet calcium phosphate cements.

The porosity of a calcium phosphate cement is a key parameter as it affects several important properties of the cement. However, a successful, non-destructive porosity measurement method that does not include drying has not yet been reported for calcium phosphate cements. The aim of this study was to evaluate isopropanol solvent exchange as such a method. Two different types of calcium phosphate cements were used, one basic (hydroxyapatite) and one acidic (brushite). The cements were allowed to set in an aqueous environment and then immersed in isopropanol and stored under three different conditions: at room temperature, at room temperature under vacuum (300 mbar) or at 37℃. The specimen mass was monitored regularly. Solvent exchange took much longer time to reach steady state in hydroxyapatite cements compared to brushite cements, 350 and 18 h, respectively. Furthermore, the immersion affected the quasi-static compressive strength of the hydroxyapatite cements. However, the strength and phase composition of the brushite cements were not affected by isopropanol immersion, suggesting that isopropanol solvent exchange can be used for brushite calcium phosphate cements. The main advantages with this method are that it is non-destructive, fast, easy and the porosity can be evaluated while the cements remain wet, allowing for further analysis on the same specimen.

Archimedes revisited: computer assisted micro-volumetric modification of the liquid displacement method for porosity measurement of highly porous light materials

Archimedes revisited: computer assisted micro-volumetric modification of the liquid displacement method for porosity measurement of highly porous light materials.

A Novel Method for Measurement of Porosity in Nanofiber Mat using Pycnometer in Filtration

Electrospun Polymer nanofibers have a wide range of applications including automotive air filters. Large surface area, small pores, flexible and adequate porosity are widely recognized as important parameters for improving the performance of the filter media and therefore measuring the porosity of the medium is extremely important. Porosity measurement techniques such as density based method, mercury porosimetry, capillary flow porometry, image analysis are relatively inaccurate and they have some disadvantages for measuring the porosity of the nano fibers. In the present study porosity measurement for nanofiber mat using pycnometer was explored. Pycnometer is generally used to measure the density of the solids of having volumes upto 150 cc. Volume of the nanofiber was measured by pycnometer and porosity is determined as fraction of the void in total volume of the fiber. Total volume is calculated from FESEM image thickness. Various advantages of pycnometry method when compared to other techniques were discussed based on the results of porosity measurements of nanofiber mats.

Laser optoacoustic method for measuring local porosity of dispersion strengthened metal-matrix composite materials

The laser optoacoustic method for porosity measurement of isotropic dispersion strengthened metal-matrix composite materials (CM) is proposed and experimentally realized. It is based on a laser thermooptical excitation of ultrasound, measurement of phase velocity of longitudinal acoustic waves in the studied material, and then application of a theoretical model for the dependence of phase velocity on porosity. The results of local porosity measurements (lateral resolution 1–2 mm) for the samples of CM based on AK12M2MgN silumin strengthened with silicon carbide particles with an average diameter 14 μm at different concentration are in agreement with the results of gravimetric measurements of the average sample porosity within the relative error of 10–15%.

Three-Dimensional Scaffolds for Tissue Engineering Applications: Role of Porosity and Pore Size

Tissue engineering applications commonly encompass the use of three-dimensional (3D) scaffolds to provide a suitable microenvironment for the incorporation of cells or growth factors to regenerate damaged tissues or organs. These scaffolds serve to mimic the actual in vivo microenvironment where cells interact and behave according to the mechanical cues obtained from the surrounding 3D environment. Hence, the material properties of the scaffolds are vital in determining cellular response and fate. These 3D scaffolds are generally highly porous with interconnected pore networks to facilitate nutrient and oxygen diffusion and waste removal. This review focuses on the various fabrication techniques (e.g., conventional and rapid prototyping methods) that have been employed to fabricate 3D scaffolds of different pore sizes and porosity. The different pore size and porosity measurement methods will also be discussed. Scaffolds with graded porosity have also been studied for their ability to better represent the actual in vivo situation where cells are exposed to layers of different tissues with varying properties. In addition, the ability of pore size and porosity of scaffolds to direct cellular responses and alter the mechanical properties of scaffolds will be reviewed, followed by a look at nature's own scaffold, the extracellular matrix. Overall, the limitations of current scaffold fabrication approaches for tissue engineering applications and some novel and promising alternatives will be highlighted.

Estimation of vegetation porosity in vegetated waterways

Vegetation porosity in a vegetated channel has been identified as the main parameter that contributes to the flow behaviour and resistance in the channel. Estimation of vegetation porosity is quite a challenging task due to the diverse characteristics of vegetation. In this study, several porosity measurement methods based on vegetation frontal area and vegetation volume were used to estimate the porosity of vegetation (Lepironia articulata) in a laboratory flume for various flow and vegetation characteristics. Digital image analysis was one of the methods used to estimate porosity. The study also involved measurements of velocity using a three-dimensional acoustic Doppler velocimeter and flow depths at different spatial locations along the flume. The volumetric method for porosity measurement, which considers the fraction of the actual volume of the vegetation to the volume of water, is considered more practical and accurate than the other methods that were studied. The results of this study indicate that, by assuming vegetation to be cylindrical in shape and considering only the frontal area of the most upstream vegetation, porosity could be underestimated by 14%. Digital image analysis gave a difference of only 5%. From the laboratory data, correlations between the mean velocity, water depth and vegetation porosity were established. It was observed that by reducing the vegetation porosity by 8%, the velocity could reduce by between 35–60% depending on flow rate.