Low Permeability Values Research Articles

The Identification of the Existence of Dispersive Soil on the Soft Soil for Dam Filling Material

Dispersive clay soils are highly erodible, even under standing water conditions. Dispersive clay soils are easily eroded both on the surface and in landfills, despite their high plasticity index and ability to be passed by water flows at low velocities. Dispersive soil will cause a variety of problems in dams and water structures, including the potential for seepage patterns in the embankment material, which can trigger piping, compromising the stability of the water structure. Dispersive soils occurring in many parts of the world are easily erodible and deflocculated in water, posing serious problems for stability of the earth and earth-retaining structures. Earth dams constructed on dispersive soils have sustained internal and external soft soil damage. The purpose of the current study was to identify the predetermine of dispersive clay soil as a filling material for the Way Sekampung Dam in Indonesia. Pinhole and Crumb tests were carried out to determine the dispersity of the original soil. This study analysed 17 undisturbed soil samples collected from 17 different locations throughout the study area. The research findings indicate that there is no evidence of dispersive soil distribution in the samples studied. According to the Pinhole and Crumb tests, all soil samples have ND-1 and 1 status, respectively. These findings are supported by laboratory test results which indicate that the soil content with a diameter greater than 0.005 mm is always less than 12% for each sample. In addition, another test revealed that the permeability value of all tested clay samples was not too low (around 10^-2 to 10^-4), indicating that they did not possess the properties of dispersive clay, which had a very low permeability value (around 10^-6 to 10^-7). In general, the clay surrounding the dam site is free from dispersive properties and is therefore safe and suitable for use as a dam filling material. Finally, these findings will be beneficial for dam constructions to understand the possibility of dispersive soil causing significant issues that require attention in geotechnical engineering.

Refinement of the petrophysical model of the Achimov formation based on facial analysis of sedimentation conditions

Aim. Due to the depletion of reserves of the main oil and gas complexes, the greatest interest is attributed to hard-to-recover reserves, complex-built objects of the sedimentary cover, the development of which was unprofitable until recently. One of these is the oil-bearing complex of the Achimov deposits of the Malobalykskoye field in Western Siberia. This article is devoted to the facies analysis and typification of reservoir rocks of the Achimov deposits in order to increase the reliability of determining the boundaries of the reservoirs, their interpretation and assessment of the petrophysical properties of the reservoirs. At the same time, special attention is paid to the facies analysis, which determines the characteristics of the reservoir. The Achimov deposits are a promising source of increasing resources and maintaining production at a high level. With their increasing importance, there are problems that complicate the search and assessment of deposits. Such problems include a high degree of reservoir compartmentalization, sharp facies variability, complex pore space structure, high clay content, low permeability values, etc. 
 
 Materials and methods. The work is based on a comprehensive interpretation of the data of the lithological description of the core, the results of laboratory studies of the core and well logging data analysis of the Achimov deposits of the Malobalykskoye field. The methods used in the interpretation of GIS data, statistical analysis, comparison. 
 
 Due to the fact that the reservoir properties of sand bodies are determined by the peculiarities of their formation in different conditions of sedimentation, it is necessary to establish a relationship between the petrophysical characteristics of rocks and their facies nature by substantiating petrofacies models. The use of the latter in geological modeling makes it possible to more effectively predict the reservoir properties (reservoir properties) of various facies lithotypes. 
 
 Results. The paper presents the results of facies analysis and typification of the reservoirs of the Achimov deposits of the Malobalykskoye field, on the basis of which the boundaries of the reservoirs and the effective oilsaturated thicknesses were refined. 
 
 Conclusions. Based on the results of the study, it can be concluded that it is necessary to develop refined petrophysical models for reservoirs with complex geological structure that take into account the facies features of rocks.

Development and characterization of whey protein films incorporated with tarbush polyphenols and candelilla wax

Edible films were prepared with whey protein incorporating candelilla wax, and glycerol in aqueous solution. Tarbush polyphenols were added as bioactive agent. An optimization based on the water vapor permeability (WVP) of the formulation was performed using a Box-Behnken design. The films were characterized by the determination of WVP, moisture, solubility, color, antioxidant and antifungal activity. Scanning electron microscopy (SEM) was also performed to observe the surface and cross-section micrographs. The lowest permeability values were found with concentrations of 1.27, 0.3 and 0.5% of protein, wax and glycerol respectively. It was proved that the addition of polyphenols into films causes a significant effect only on solubility and transparency characteristics. Edible films have suitable properties as a barrier for the goods they could be applied on. It is proposed for use in foods such as fresh or minimally processed fruits and vegetables.

Interaction of rock-bolt supports while weak rock reinforcing by means of injection rock bolts

Purpose is to analyze changes in shape and dimensions of a rock mass area, fortified with the help of a polymer, depending upon the density of injection rock bolts as well as the value of initial permeability of enclosing rocks to substantiate optimum process solutions to support roofs within the unstable rocks and protect mine workings against water inflow and gas emission. Methods. Numerical modeling method for coupled processes of rock mass strain and filtration of liquid components of a polymer has been applied. The model is based upon fundamental ideas of mechanics of solids and filtration theory. The problem has been solved using a finite element method. Its solution took into consideration both the initial permeability and the permeability stipulated by mine working driving, injection time of reagents and their polymerization, and effect of po-lymer foaming in the process of mixing of its components. Changes in physicomechanical and filtration characteristics of rock mass during polymer hardening were simulated. It has been taken into consideration that a metal delivery pipe starts operating as a reinforcing support element only after the polymer hardening. Findings. If three and five injection rock bolts are installed within a mine working section then stresses, permeability coefficients, pressure of liquid polymeric composition, and geometry of the fortified area of rock mass have been calculated. It has been shown that rock bolt location is quite important to form a rock-bolt arch. It has been demonstrated for the assumed conditions that if five injection rock bolts are installed within the mine working roof then close interaction between rock-bolt supports takes place; moreover, the integral arch is formed within the mine working roof. Originality. Dependence of change in the polymer reinforced area upon a value of initial permeability of enclosing rocks has been derived. It has been shown that in terms of low values of initial permeability, geometry of rock-bolt supports as well as its size is identified only by means of a value of the unloaded zone around the mine working. In this context, initial permeabi-lity increase results in the enlarged diameter of the reinforced rock mass area in the neighbourhood of the injection rock bolt. Practical implications. The findings are recommended to be applied while improving a method to support the mine working roof and decrease water inflow as well as gas emission from the rocks, being undermined, into the working.

Effect of Chitosan Nanoparticles Incorporating Antioxidants from Salvia hispanica L. on the Amaranth Flour Films.

SUMMARYResearch backgroundAmaranth (Amaranthus hypochondriacus) flour produces films with excellent barrier properties against water vapor, allowing food preservation, but the mechanical properties are poor compared to synthetic films. One strategy to improve these properties is the incorporation of nanoparticles. The particles can also serve as a vehicle for the addition of antioxidant agents into the films. The objective of this work is to optimize the formulation for the preparation of amaranth flour films treated with antioxidant chia (Salvia hispanica L.) extract-loaded chitosan particles using response surface methodology (RSM).Experimental approachChitosan nanoparticles with the extract were synthesized by ionic gelation, and the films were made by the casting method. Three independent variables were assigned: amaranth flour (4-6%), glycerol (25-35%) and chitosan nanoparticles loaded with the chia extract (0-0.75%). We then evaluated the physical (thickness), mechanical (tensile strength, Young´s modulus and elongation), barrier (water vapor permeability, moisture and water solubility) and antioxidant properties of the films. The experimental results of the properties were analyzed using a Box-Behnken experimental design generating 15 runs with three replicates at the central point.Results and conclusionsSecond and third order polynomial models were obtained from the ANOVA analysis of the evaluated responses, and high coefficients of determination were found (0.91–1.0). The water vapor permeability of the films was 0.82−2.39·10-7 (g·mm)/(Pa·s·m2), tensile strength was 0.33−1.63 MPa and antioxidant activity 2.24−5.65%. The variables had different effects on the films: glycerol negatively affected their properties, and the permeability values increased with increased amaranth flour content. The nanoparticles improved the mechanical, barrier and antioxidant properties of the films compared to the films without nanosystems. The optimal formulation was 4% amaranth flour, 25% glycerol and 0.36% chitosan nanoparticles. The optimized films had better mechanical (1.62 MPa) properties, a low water vapor permeability value (0.91·10-7 (g·mm)/(Pa·s·m2)) and moderate antioxidant activity (6.43%).Novelty and scientific contributionThe results show the effect of chitosan nanoparticles on the properties of amaranth flour films for the first time. The resulting equations are useful in the design of food packaging.

The challenge in measuring low-permeability materials: a comparison of different approaches

Abstract. The German repository site selection procedure calls for a radioactive waste containment zone with a low-permeability host rock (kf<10-10 m s−1, StandAG §23, 5) and long-term sealing by barrier materials (EndlSiAnfV, 2020; ESK, 2019). The potential host rocks, clay and rock salt, as well as the considered barrier materials, bentonite and compacted crushed salt, show permeability in the range of kf∼10-16 m s−1 (K∼10-21 m2). These low values suggest that advective flow is as slow as diffusive mass flux. Measuring such low permeability with adequate accuracy challenges measurement setups and respective error evaluation. Methodologies. Several low-permeability measurements are carried out by transient tests, e.g. by monitoring controlled fluid pressure changes in: (1) pressure decay and (2) oscillating pulse tests. The first method (1) deviates permeability from the time needed to compensate pressure differences through the sample. The latter (2) monitors phase shift and amplitude attenuation of controlled pressure pulses passing through the sample. Any permeability measurement needs to be post-processed, e.g. for: (1) material-intrinsic controls (saturation state, storativity, the fluids' compressibility, etc.), (2) environmental controls (temperature, confining pressures, etc.) and (3) theoretical considerations (Klinkenberg correction, multi-phase wetting angles, etc.). Salts. A porosity-permeability relation was found down to K=10-19 m2 (e.g., Popp et al., 2007). Testing fluids were NaCl brine, oils, He and N2 as a fluid. As a matter of current research, a critical, low-permeability value might be associated with the so-called “percolation threshold” that defines the minimal requirements for an interconnected pore system (e.g., DAEF, 2016). Clays. A major challenge is the long duration of sample saturation (up to several months) and pressure equilibration (often days), as well as precise, temperature-compensated measuring and the determination of the samples' storativity (e.g., Winhausen et al., 2021). Testing fluids are commonly designed mixtures mimicking the rocks' pore waters. Geotechnical barrier materials. The permeability testing performed is similar to that of salt and clays mentioned above. However, both barrier materials, crushed salt and bentonite, have significant permeability early after emplacement. This is beneficial, as it allows the outflow of unwanted canister corrosion gases. Eventually, the permeability drops by orders of magnitude and the barriers become tight seals in the long-term. Here, identifying the gas entry/breakthrough pressure has been valuable (e.g., Rothfuchs et al., 2007). Figure 1 shows a preliminary sensitivity analysis as an example of pressure decay measurements. It suggests that the pressure equilibration term (c), and hence the test duration, is most sensitive to the calculation of low permeability. However, the large variation of (representative) material and environmental controls make permeability measurements complex. This workshop aims to encourage discussions on uncertainty and sensitivity of the influencing controls, such that it may lead to a “best-practice” guide for permeability measurements.

Investigation of Duplex Brass Membranes with Metallography, Permeability and Treatments: Work-Hardening, Annealing and Quenching

This paper consists of the fabrication and investigation of metal membranes and the study of their behaviour and applications in gas separation processes. The scope is to produce and characterize the porous crystal structure of brass alloy (standardization: DIN 17660) membranes and measure their permeability with helium as a penetrant medium. Another part of this study is to alter the brass alloy’s structure throughout metallurgical treatments and investigate how the permeability is allied to the structure’s alteration. This work merges the knowledge and technology of inorganic porous materials science in metallurgy. The novelty of the current research resides in the process to alternate the brass alloy structure throughout metallurgical treatments and how it is allied to the permeability of the membrane, which is of interest to be investigated. The results of the research are analysed and compared conducting the final inferences. All metallurgical treatments resulted in low permeability values when compared to a non-treated specimen. Specifically, the drop in permeance ranged from 76 up to 99.56%. It is noted that consecutive treatments contributed to even further decreases.

Crack formation behavior of composite fly ash – bentonite (FAB) in landfill liner system

This study aims to investigate the influence of different mixtures on the phenomenon of desiccation cracking in bentonite-fly ash mixtures as a landfill liner system. Fly ash is quite potential to be used as a landfill liner mixture because it has a low hydraulic permeability or conductivity value. This study uses class F fly ash from the Paiton power plant production process, Indonesia, which has been distributed commercially. Desiccation test was conducted in this study. The composition of fly ash and bentonite which is used are pure fly ash (FAB0), fly ash and bentonite 15% (FAB15), fly ash and bentonite 20% (FAB20) and fly ash and bentonite 25% (FAB25). The smallest CIF value is found in the pure fly ash layer. However, the pure fly ash cannot be used as landfill liner because the high permeability value. Therefore, the addition of bentonite will increase the possibility of crack formation. This study reveals that the addition bentonite in the fly ash composite will increase the crack. However, determining appropriate mixture composition is critical when working on the landfill liner system.

Multilayer Films Based on Poly(lactic acid)/Gelatin Supplemented with Cellulose Nanocrystals and Antioxidant Extract from Almond Shell By-Product and Its Application on Hass Avocado Preservation.

In this work, poly(lactic acid) (PLA)/gelatin/PLA multilayer films supplemented with cellulose nanocrystals and antioxidant extract from almond shell (AS) by-products were developed by solvent casting technique for active food packaging. The almond shell antioxidant extract (ASE) was obtained by microwave-assisted extraction, while cellulose nanocrystals (CNCs) were extracted from AS by a sequential process of alkalization, acetylation and acid hydrolysis. Four formulations were obtained by adding 0 (control), 6 wt.% of ASE (FG/ASE), 4.5 wt.% of CNCs (FG/CNC) and 6 wt.% + 4.5 wt.% of ASE + CNCs, respectively, (FG/ASE + CNC) into fish gelatin (FG). PLA/FG/PLA multilayer films were prepared by stacking two outer PLA layers into a middle FG film. A surface modification of PLA by air atmospheric plasma treatment was optimized before multilayer development to improve PLA adhesion. Complete characterization of the multilayers underlined the FG/ASE + CNC formulation as a promising active reinforced packaging system for food preservation, with low values of transparency, lightness and whiteness index. A good adhesion and homogeneity of the multilayer system was obtained by SEM, and they also demonstrated low oxygen permeability (40.87 ± 5.20 cm3 mm m−2 day) and solubility (39.19 ± 0.16%) values, while mechanical properties were comparable with commercial plastic films. The developed multilayer films were applied to Hass avocado preservation. The initial degradation temperature (Tini), DSC parameters and in vitro antioxidant capacity of the films were in accordance with the low peroxide and anisidine values obtained from avocado pulp after packaging for 14 days at 4 °C. The developed PLA/FG/PLA films supplemented with 6 wt.% ASE+ 4.5 wt.% CNCs may be potential bioactive packaging systems for fat food preservation.

New Blood-Brain Barrier Models Using Primary Parkinson's Disease Rat Brain Endothelial Cells and Astrocytes for the Development of Central Nervous System Drug Delivery Systems.

Parkinson's disease (PD) is a progressive neurodegenerative disorder characterized by motor system defects due to the loss of dopaminergic neurons. A significant contributor to the current limited therapeutic treatments for PD is the poor penetration of potential drugs through the blood-brain barrier (BBB). The BBB is a highly specialized neurovascular system that separates components of the circulating blood from neurons. There is a great need to develop in vitro BBB models that retain fundamental characteristics and reliably predict the permeability of drug candidates. BBB breakdown may initiate and/or contribute to neuronal dysfunction and loss in diseases such as PD. However, there is no in vitro BBB model that mimics the pathological state of PD. To construct in vitro BBB models for drug delivery systems in the developing central nervous system (CNS), we isolated high purity endothelial cells from both normal and PD rat brain microvessels. The primary rat endothelial cell cultures maintained the properties of their in vivo counterparts. We developed and characterized in vitro rat endothelial cell and C6 glial cell coculture BBB models. We further examined the morphological and functional integrity of the barriers. The in vitro coculture BBB models we established displayed the typical cytoarchitecture and cellular markers by immunofluorescence staining and electron microscopy, high transendothelial electrical resistance (>300 Ω cm2), and a low permeability value (<3 × 10-6 cm/s). Our new models can be used to study BBB dysfunctions in relation to the pathogenesis and progression of PD, as well as a screening tool to test candidate drugs for PD treatment.

Linear and Nonlinear Biphasic Mechanical Properties of Goat IVDs Under Different Swelling Conditions in Confined Compression.

To define technical specifications for artificial substitutes, it is necessary to model their mechanical behaviour. Here we studied the linear and nonlinear biphasic models for Nucleus Pulposus (NP) and Annulus Fibrosus (AF). The associated material parameters were obtained using confined compression stress relaxation tests on goat intervertebral disc (IVD) samples. The first parameter, aggregate modulus HA0, which essentially describes load-bearing capacity of the solid phase, was larger for AF (HA0 = 0.53±0.06 MPa) than for NP (HA0 = 0.26±0.04 MPa). For hydraulic permeability, which quantifies the ability to transmit interstitial fluid, it was the opposite (k0 = (0.20±0.07) × 10-15 m4/Ns for AF and k0 = (0.67±0.08)×10-15 m4/Ns for NP). The values of nonlinearity coefficients, nonlinear stiffening coefficientβ and non-dimensional nonlinear permeability coefficient M, reflected that these tissues had nonlinear elastic behaviour and permeability. Also, investigating the effect of swelling conditions in sample preparation showed that for both AF and NP, confined-swollen samples had higher aggregate modulus and lower permeability values compared to the free-swollen ones. The quantitative description of the nonlinear properties of AF and NP provided a better understanding of IVD behaviour as well as technical specifications for their artificial substitutes.

Prediction of Ovarian Follicular Dominance by MRI Phenotyping of Hormonally Induced Vascular Remodeling

In the mammalian female, only a small subset of ovarian follicles, known as the dominant follicles (DFs), are selected for ovulation in each reproductive cycle, while the majority of the follicles and their resident oocytes are destined for elimination. This study aimed at characterizing early changes in blood vessel properties upon the establishment of dominance in the mouse ovary and application of this vascular phenotype for prediction of the follicles destined to ovulate. Sexually immature mice, hormonally treated for induction of ovulation, were imaged at three different stages by dynamic contrast-enhanced (DCE) MRI: prior to hormonal administration, at the time of DF selection, and upon formation of the corpus luteum (CL). Macromolecular biotin-bovine serum albumin conjugated with gadolinium-diethylenetriaminepentaacetic acid (b-BSA-GdDTPA) was intravenously injected, and the dynamics of its extravasation from permeable vessels as well as its accumulation in the antral cavity of the ovarian follicles was followed by consecutive T1-weighted MRI. Permeability surface area product (permeability) and fractional blood volume (blood volume) were calculated from b-BSA-GdDTPA accumulation. We found that the neo-vasculature during the time of DF selection was characterized by low blood volume and low permeability values as compared to unstimulated animals. Interestingly, while the vasculature of the CL showed higher blood volume compared to the DF, it exhibited a similar permeability. Taking advantage of immobilized ovarian imaging, we combined DCE-MRI and intravital light microscopy, to reveal the vascular properties of follicles destined for dominance from the non-ovulating subordinate follicles (SFs). Immediately after their selection, permeability of the vasculature of DF was attenuated compared to SF while the blood volume remained similar. Furthermore, DFs were characterized by delayed contrast enhancement in the avascular follicular antrum, reflecting interstitial convection, whereas SFs were not. In this study, we showed that although DF selection is accompanied by blood vessel growth, the new vasculature remained relatively impermeable compared to the vasculature in control animal and compared to SF. Additionally, DFs show late signal enhancement in their antrum. These two properties may aid in clinical prediction of follicular dominance at an early stage of development and help in their diagnosis for possible treatment of infertility.

Impact of diagenesis on the reservoir rock quality of the Cachiri Group tight sandstones in Cesar sub basin (Colombia): A case of study from ANH-CR-MONTECARLO 1X well

Basal sandstones of the studied interval in the Cesar Sub-basin (Colombia), have reported manifestations of hydrocarbons in the ANH CR MONTECARLO 1X well, so they have been studied as a possible unconventional reserve rock. Diagenesis plays an important role in assessing the quality of a reservoir rock, so this study presents an analysis of the diagenetic evolution in basal sandstones of the Cachiri Group in Cesar Sub-basin. Based on the petrographic and core data, diagenetic products have been determined, and how these have intervening in the quality as a possible reservoir rock. These sandstones with fine to medium grain sizes, poor to the moderate selection, are classified as arches and lithic arches. Core data porosity reveals a range between 0.06 and 2.1% and a permeability of 0.02–0.049 millidarcys (mD). These low porosity and permeability values are mainly controlled by the mechanical compaction process. Cement precipitation (carbonate, silica) also leads to a reduction in the porosity and permeability of these rocks. Other diagenetic products that can be evidenced in these sandstones are related to the metasomatism of feldspar grains by carbonate and ferrous carbonate, and dissolution of feldspar and lithic fragments.

MECHANICAL PROPERTIES OF POLYSULFONE-ZnO NANOCOMPOSITE MEMBRANE

Large quantities of wastewater are generated by the petroleum refining process. Micron-scale emulsion droplets and submicron droplets are difficult to remove from oil-refined wastewater, and addressing these issues has been a major challenge for researchers. Membrane technology is widely used in water treatment because it is very selective and effective in the filtration process. his research focuses on oil refinery water treatment using a polysulfone membrane (PSF)-nano-ZnO membrane with the addition of polyethylene glycol (PEG). This research aims to determine the PEG ratio that produces the optimum PSF-ZnO membrane in terms of mechanical properties, including thickness, tensile strength, and molecular weight cut-off (MWCO) value. The membranes with the optimum clearance were obtained at 3% PEG with a thickness of 0.0077 mm, Young's modulus of 8800 N/m2, and Morphological analysis was performed using the SEM (Scanning Electron Microscopy) method on the membrane which had the highest and lowest permeability values.. The best membrane MWCO value was achieved by the addition of 19% PSF-nano-ZnO 1% wt at 5 minutes of UV irradiation. This shows that the addition of PEG composite affects pore openings. The membrane formed with variations in PEG concentrations affecting the thickness of the membrane. Higher concentrations make the membrane thicker, resulting in a higher Young’s modulus.

CO2 Capture and Storage Performance Simulation in Depleted Shale Gas Reservoirs as Sustainable Carbon Resources

Underground carbon capture and sequestration (CCS) is a useful technique for separating this kind of greenhouse gas from atmosphere and store it under the surface of the earth. As a matter of fact, CO2 can be transferred to underground petroleum reservoirs which are initially contained oil and gas, or aquifers which are initially saturated with water. This kind of CCS takes place using an injection well which is drilled from surface to the target underground bedrocks. A shale gas reservoir (SGR) is a type of petroleum gas reservoir in which natural gas is stored in ultra-tight pores of the shale rock. In this study, a flow modeling analysis in SGR with a multi-stage fractured horizontal well (MSFHW) is conducted using numerical simulation. In this shale layer, a horizontal well is drilled and several transverse hydraulic fractures, for increasing the flow efficiency between the well and porous medium, are created. The studied SGR – a depleted reservoir acting as a macroscopic sustainable material for the CCS – is initially saturated with methane gas, and carbon dioxide is required to be injected for the storage. The most outstanding results of this study is about sensitivity analyses for SGR permeability with different conditions of gas adsorption and stress-dependent permeability which are from important features of SGRs. The results show a minor reduction in cumulative gas injection due to the effect of stress-dependent permeability in all measures for reservoir permeabilities. Furthermore, gas sorption shows a considerable positive correlation with CO2 storage response in high-permeability SGR and a minor increasing effect on SGRs with lower permeability values.

Physical properties of Cretaceous to Eocene platform-to-basin carbonates from Albania

Understanding acoustic velocities of sedimentary deposits is crucial for realistic subsurface imaging. The velocities rely on mineralogy, density, as well as pore volume (porosity) and pore structure. In carbonate rocks, both depositional and diagenetic histories exert a significant control on these characteristics. In order to determine this control, petrographic analysis (thin sections) associated with the analysis of the carbonate content, grain density, permeability, porosity, and acoustic measurements were performed on samples from Cretaceous to Eocene carbonate platform-to-basin series of Albania. Rock facies showed two depositional associations and four pore-type associations. Very low average permeability (<1 mD) and variable porosity values (0–14%) characterize the samples. Pore type and diagenetic alteration steered the porosity-permeability distribution. Modelling of the velocity-porosity relationship, using the differential effective medium theory (DEM), revealed that variations in the acoustic velocity were mainly driven by variations in porosity and pore type, while facies and mineralogy were of minor importance.The Albanian dataset was compared with petrophysical data retrieved from time- and deep-water facies equivalent carbonate series of the Gargano Promontory in Italy. The comparison demonstrates that the variation in acoustic velocity is limited within the Albanian samples due to the pronounced infill of primary and secondary pores. Acoustic velocity data, on the other hand, are more scattered for the Gargano and this is essentially related to the higher porosity due to the preserved primary macro-intergranular and micro-intercrystalline pores, and/or to significant development of secondary mouldic pores.This study contributes to the understanding of heterogeneities and spatial distribution of pore types resulting in different petrophysical signatures of Cretaceous platform to deep-water carbonates. The data provide a better insight into possible variations in reservoir quality and seismic signature of these types of carbonates in subsurface reservoirs.

Post Treatment Acidizing Study on Carbonate Rock with Wormhole Radius Method

The problem that generally occurs in production activities is that wells in producing conditions has a low production rate. This could be due to the low permeability value of the reservoir or the increase of the skin factor of the reservoir due to formation damage. This matrix acidizing stimulation method is considered as an effective method in terms of activity costs and the success ratio in carbonate rocks. One of the successes of increasing the permeability around the well area depends on how far the wormholes are formed around the well. The results showed that the fractal dimension and wormhole radius model approach can be used to analyze the post treatment skin effect after validating the field data. Further analysis was carried out by involving limestone and dolomite reservoirs which have different characteristics in terms of porosity, permeability and fractal dimensions. The two reservoirs require different volumes of acid injection to produce the same reduction in skin factor. In this research, it is found that the parameters of permeability ratio, fractal dimensions, acid concentration, rock porosity and type of lithology affect the post treatment skin factor.

Sulfonated polyvinylidene fluoride and functional copolymer based blend proton exchange membrane for fuel cell application and studies on methanol crossover

Copolymers of poly(methyl methacrylate)-co-poly (2-acrylamido-2-methyl-1-propane sulfonic acid (PMMA-co-PAMPS) have been prepared via radical polymerization with different MMA to AMPS mol ratio and blended with polyvinylidene fluoride (PVDF) and sulfonated PVDF (S-PVDF) in a different weight ratio to prepare proton exchange membranes (PEMs) by simple solution casting method for fuel cells application (PEMFCs). Five different PEMs have been prepared from only PMMA-co-PAMPS, blending PMMA-co-PAMPS with PVDF, and also by blending PMMA-co-PAMPS with S-PVDF to get the suitable membrane for PEMFCs application. We have also studied the effect of PVDF and S-PVDF in the blend membranes on the water uptake, mechanical stability, thermal stability, proton conductivity (Km), and methanol permeability (PM) properties. PEMs prepared by blending with S-PVDF exhibited high Km and low PM value. PEM-5 membrane prepared by blending S-PVDF with PMMA-co-PAMPS (30:70 w/w) exhibited Km at room temperature 5.7 × 10−2 S/cm, PM value 5.24 × 10−7 cm2/s and maximum power density 477 mW/cm2. This PM value is much lower than that of the Nafion® 117 membrane (22 × 10−7 cm2/s). This low PM, high Km and high selectivity make the S-PVDF blend membranes a good candidate in PEMFCs or direct methanol fuel cells (DMFCs) application.

Effect of the Flow Rate on the Relative Permeability Curve in the CO2 and Brine System for CO2 Sequestration

The relative permeabilities of CO2 and brine are important parameters that account for two-phase flow behavior, CO2 saturation distribution, and injectivity. CO2/brine relative permeability curves from the literature show low endpoint CO2 permeability values and high residual brine saturation values. These are the most distinguishing aspects of the CO2/brine relative permeability from oil/water and gas/oil. In this study, this aspect is investigated experimentally by employing a wide range of CO2 injection flow rates. As a result, all the measurements align with previous studies, having low endpoint relative permeability and high residual brine saturation values. They have obvious relationships with the changes in CO2 flow rates. As the CO2 flow rate increases, the endpoint relative permeability increases, the residual brine saturation decreases, and they converge to specific values. These imply that a high CO2 injection flow rate results in high displacement efficiency, but the improvement in efficiency decreases as the flow rate increases. The reasons are identified with the concept of the viscous and capillary forces, and their significance in the CO2 injection into a reservoir is analyzed.

Metal industry waste desiccation behavior with the addition of bentonite as a landfill liner

The existence of garbage in the environment can cause pollution. Therefore, it is necessary to carry out waste management, one of which is by building a landfill. Landfill liner should have a permeability coefficient <10−6 cm/sec to prevent contamination. Currently, the affordable material used as landfill liner is clay, but it is quite rare. An alternative material we can use is metal industrial waste, which has not been utilized. Metal industrial waste has a permeability coefficient, namely 25.34560 x 10−6 cm/s. In order to reduce the permeability coefficient value, metal industrial waste is added with bentonite material, which has a low permeability value with variations of 0%, 5%, 10%, 15%, 20%, and 25% addition of bentonite. Digital image processing techniques are used to calculate crack intensity factor (CIF) values using the Matlab 2019 software. The results showed that the permeability value that fulfilled was the variation of 20% bentonite addition of 0.8059 x 10−6 cm/s and 25% of 0.5059 x 10−6 cm/s. While the CIF results showed that only the variation of 25% bentonite addition were not eligible because they had a crack area >4%. Thus it can be concluded that the best composite is metal industrial waste with 20% bentonite.