scholarly journals Experimental Study on the Effect of Long-Term Water Injection on Micropore Structure of Ultralow Permeability Sandstone Reservoir

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Shiyuan Qu ◽  
Hanqiao Jiang ◽  
Junjian Li ◽  
Lin Zhao ◽  
Changhui Wu
Keyword(s):  
Pore Radius ◽  
Water Injection ◽  
Average Pore ◽  
Average Pore Radius ◽  
Flow Channels ◽  
Pore Structures ◽  
Before And After ◽  
The Right ◽  
Ultralow Permeability

During the long-term waterflooding (LTWF) in oil reservoirs, the formation is subject to permeability reduction as clay release and fine migration. At present, the mechanisms of permeability impairment in both macroscopic and microscopic pore structures in ultralow permeability reservoirs under LTWF are unclear. This statement epitomizes the main objective of this work: to understand how long-term waterflood changes porous structures and thus compromises permeability. The standard core flow experiments in conjunction with a couple of tests consisting of online nuclear magnetic resonance (NMR), high-pressure mercury intrusive penetration (HPMIP), X-ray diffraction (XRD), and scanning electron microscope (SEM) were performed to determine the mineral compositions, macrophysical properties, and micropore structures of two kinds of cores with different natures of pore distribution (i.e., unimodal and bimodal) before and after LTWF in Yan Chang field China. Results showed that the permeability decreased while the porosity increased after the LTWF. With respect to the pore size distribution, the small pores (SPs) decreased and the large pores (LPs) increased for both cores. For the unimodal core, the distribution curve shifted upwards with little change in the radius of the connected pores. For the bimodal core, the curve shifted to the right with an increasing radius of connected pores. With respect to the characteristic parameters, the average pore radius, median pore radius, structural coefficient, and tortuosity increased, while the relative sorting coefficient decreased. The relative changes of the parameters for the unimodal core were much smaller than those for the bimodal core. With respect to the clays, chlorite accounted for a majority proportion of the clays, and its content increased after LTWF. According to these changes, the mechanism of LTWF at different stages was interpreted. At the early stages, the blockage of the released clays occurred in SPs. Some of the middle pores (MPs) and LPs became larger due to the release and some of them became smaller due to the accumulation. At the middle stage, the blockage of SPs weakened. Some flow channels formed by MPs and LPs became dominant flow channels gradually. The effluxes of particles occurred, resulting in a significant increase in porosity. At the late stage, the stable flow channels have formed. The higher response of the bimodal core to LTWF could be attributed to its higher content of chlorite, which was more likely to accumulate. This study clarifies the mechanism of fine-migration-induced formation damage in microscopic pore structures and the migration pattern of clay minerals in ultralow permeability reservoirs. The work provides potential guidance for optimizing waterflood strategies in ultralow permeability reservoirs.

scholarly journals ACTIVITY TEST AND REGENERATION OF NiMo/Z CATALYST FOR HYDROCRACKING OF WASTE PLASTIC FRACTION TO GASOLINE FRACTION

2010 ◽  
Vol 5 (3) ◽  
pp. 261-268 ◽  
Author(s):  
Rodiansono Rodiansono ◽  
Wega Trisunaryanti
Keyword(s):  
Natural Zeolite ◽  
Pore Radius ◽  
Total Pore Volume ◽  
Acid Sites ◽  
Gasoline Fraction ◽  
Total Acid ◽  
Average Pore ◽  
Average Pore Radius ◽  
Activity Test ◽  
Hydrogen Stream

Activity test and regeneration of NiMo/active natural zeolite catalyst for hydrocracking of waste plastic fraction of polyprophylene (PP) type have been carried out. The catalysts was prepared by loading Mo followed by Ni Metals onto the natural zeolite (Z) sample, then calcined at 500oC, oxidized and reduced at 400oC under nitrogen, oxygen and hydrogen stream, respectively. The characterization of catalysts including spesific surface area, average pore radius, and total pore volume were performed by gas sorption analyzer, amount of total acid sites was determined by gas sorption method, and acid site strength was confirmed by IR spectroscopy. The hydrocracking process was carried out in a semi-flow reactor system at 360 oC and catalyst:feed ratio 0.5 under hydrogen stream (150 mL/hour). The feed was vaporized from the pyrolisis reactor into the hydrocracking reactor. A liquid product was collected and analyzed by gas chromatography (GC) and gas chromatography-mass spectroscopy (GC-MS). The characterization results showed that spesific surface area, average pore radius, and total pore volume of the Z sample decreased after loading of the Ni and Mo metals. Amount of total acid sites of the NiMo/Z catalyst was higher than that of the Z sample. The activity of NiMo/Z catalyst decreased after several continously runs. Its regeneration produced the NiMo/Z reg catalyst with similar activity and selectivity to the fresh catalyst (NiMo/Z). The activity of catalysts at the optimum condition followed the order of NiMo/Z reg>NiMo/Z>Z (conversion of hydrocarbon C>12) and NiMo/Z reg>NiMo/Z>Z (total yield of gasoline fraction). The selectivity of catalysts for C7-C8 product followed the order of Z>NiMo/Z>NiMo/Z reg. Keywords: activity, polyprophylene, catalyst, gasoline fraction.

scholarly journals Structure, Texture and Catalytic Properties of CuO/Fe2O3 and CuFe2O4

1996 ◽  
Vol 13 (6) ◽  
pp. 469-477 ◽  
Author(s):  
A.M. Youssef ◽  
G.E. Badr ◽  
Th. El-Nabarawy
Keyword(s):  
Pore Radius ◽  
Catalytic Properties ◽  
Textural Properties ◽  
Nitrogen Adsorption ◽  
Average Pore ◽  
Average Pore Radius ◽  
Temperature Range ◽  
Thermal Product ◽  
Xrd Patterns ◽  
Co Precipitation

CuO/Fe2O3 (1:1) was prepared by co-precipitation. Six thermal products (I–VI) were obtained by calcination in the temperature range 300–800°C. The structures of I–VI were determined from XRD patterns and they were also identified from electrical conductivity measurements in the temperature range 313–523 K. The textural properties were determined from nitrogen adsorption at 77 K and the acidities of the thermal product were measured by pyridine chemisorption at 423 K. The decomposition of H2O2 over the catalysts I–VI was followed in the temperature range 303–323 K. Conversion of 2-propanol was investigated at 523 K. Calcination of CuO/Fe2O3 at 600°C resulted in partial transformation to CuFe2O4, this transformation predominating at 700°C and being complete at 800°C. Two mechanisms of electrical conduction are involved for catalysts calcined at 600–800°C depending on the temperature at which σ is measured. The surface area decreases and the average pore radius increases with increasing calcination temperature due to sintering and spinel formation. A mechanism is suggested for H2O2 decomposition and the activity and selectivity of the catalysts towards the conversion of 2-propanol are discussed.

scholarly journals ANALISIS KINERJA KEUANGAN BADAN USAHA MILIK NEGARA(BUMN) PASCA PRIVATISASI

2019 ◽  
Vol 5 (1) ◽  
pp. 1
Author(s):  
Abubakar Arif ◽  
Husein Ukassa
Keyword(s):  
Financial Performance ◽  
Full Scale ◽  
Time Interval ◽  
Return On Equity ◽  
Paired Samples ◽  
Good Corporate Governance ◽  
Before And After ◽  
The Right ◽  
Turn Over

<p class="Style1"><em>This research was aimed to know the financial's performance of state company (BUMN) before and after privatized, so that it could be known whether privatizes was the right solution to fix BUMN'S perfonnance. This observational data acquired from BUMN's corporate which was privatized upon year 2002 by Initial Public Offering's methods (IPO), the firms among those were PT. Kimia Farma Tbk. , PT. Indofarma Thk. , PT. Tambang Batubara Bukit Asam Tbk. , and PT. Perusahaan Gas Negara Thk The sample on this research was the financial performance of BUMN's corporate which was privatized with time interval of three years (period) before and after privatizes. The financial performance measured by eight indicators, that amongst those: Return On Equity (ROE), Return On Investment (ROI), Cash Ratio, Collection Periods, Inventory Turn Over, Full scale Revaluation Turn Over, Equities Totaled ratio to Full Scale Revaluation. The analysis's method data that is utilized is one sample ofKolmogrov Smirnov, and Paired Samples Test. The results of the analysis found that BUMN's financial performance which privatized by <strong>IPO </strong>method was not made much progress, even some indicator of finance's performance decreased. It even bastioned by yielding hypothesizing examination that shows that there were not differentiate and poor relationship in finance's performance before and after privatized. However, privatizes is supposed to not only aims to close deficit RAPBN, but in long-term the managements of corporate performance shall get to show openness, independence, naturalness, and accountabilities to reach good corporate governance. Nevertheless, in world trade there are just a firm that have good performance will gets to pull investor candidate to imbed its capital</em></p>

Effect of Membrane Pore Size and Membrane-Solute Interactions on Lysozyme Ultrafiltration

2006 ◽  
Vol 514-516 ◽  
pp. 1483-1487
Author(s):  
Vitor Magueijo ◽  
Viriato Semião ◽  
Maria Norberta de Pinho
Keyword(s):  
Molecular Weight ◽  
Pore Size ◽  
Pore Radius ◽  
Double Layers ◽  
Hydraulic Permeability ◽  
Average Pore ◽  
Average Pore Radius ◽  
Electric Double Layers ◽  
Membrane Pore ◽  
Cellulose Acetate Membranes

A model based on steric hindrance mechanisms [1] is used to determine the pore sizes of two ultrafiltration (UF) membranes. The lysozyme rejection coefficients of those membranes are predicted through the same model after modification of the pore size and solute radius by taking into account the development of electric double layers. Two asymmetric cellulose acetate membranes M1 and M2 were prepared and characterized. Membrane M1 has an hydraulic permeability of 2.1x10-6 m/s/bar, a molecular weight cut-off (MWCO) of 30,000 Da and an average pore radius of 2.6 nm. Membrane M2 has an hydraulic permeability of 5.9x10-6 m/s/bar, a molecular weight cut-off (MWCO) of 60,000 Da and an average pore radius of 5.3 nm. Aqueous solutions of lysozyme containing a NaCl concentration of 0.1M were ultrafiltrated through membranes M1 and M2. The predicted lysozyme rejections considering the development of electric double layers on the protein and membrane pore surfaces, are in good agreement with the experimental results.

Porous alumina ceramics by spray-pyrolyzed powder from aluminum sulfate and aluminum nitrate solutions

1994 ◽  
Vol 9 (7) ◽  
pp. 1709-1713 ◽  
Author(s):  
Kiyoshi Okada ◽  
Akihiro Tanaka ◽  
Shigeo Hayashi ◽  
Keiji Daimon ◽  
Nozomu Otsuka
Keyword(s):  
Pore Size ◽  
Aluminum Sulfate ◽  
Pore Radius ◽  
Nitrate Solution ◽  
Sulfate Solution ◽  
Aluminum Nitrate ◽  
Alumina Ceramics ◽  
Average Pore ◽  
Average Pore Radius ◽  
Nitrate Solutions

Porous α-alumina ceramics were prepared using the spray-pyrolyzed powder from aluminum nitrate solution and aluminum sulfate solution. Porosity and pore size distribution of the samples were examined with respect to the forming pressure and firing temperature. The porosity obtained changed from around 80% in the green compacts to 60–70% in the fired bodies fired at 1500 °C. The porosity of 30–40% remained even by firing at 1700 °C. Although there was no significant difference in the porosity of the fired bodies prepared from the sulfate and nitrate solutions, the fired bodies prepared from the nitrate solution showed apparently larger pore size than those from the sulfate solution. Fired bodies with an average pore radius from 0.2 to 0.8 μm can be prepared by this method. The four-point bending strength of the fired bodies, which had a porosity of 57% and an average pore radius of 0.23 μm, was 35 MPa.

scholarly journals Критерий подобия сверхзвукового обтекания цилиндра с передней высокопористой ячеистой вставкой

2018 ◽  
Vol 44 (6) ◽  
pp. 3
Author(s):  
С.Г. Миронов ◽  
Т.В. Поплавская ◽  
С.В. Кириловский ◽  
А.А. Маслов
Keyword(s):  
Mach Number ◽  
Drag Coefficient ◽  
Pore Diameter ◽  
Pore Radius ◽  
Aerodynamic Drag ◽  
Similarity Criterion ◽  
High Porosity ◽  
Average Pore ◽  
Average Pore Radius ◽  
Supersonic Airflow

AbstractWe have experimentally and numerically studied the influence of the ratio of the diameter of a cylinder with a frontal gas-permeable porous insert made of nickel sponge to the average pore diameter in the insert on the aerodynamic drag of this model body in supersonic airflow ( M _∞ = 4.85, 7, and 21). The analytical dependence of the normalized drag coefficient on a parameter involving the Mach number and the ratio of cylinder radius to average pore radius in the insert is obtained. It is suggested to use this parameter as a similarity criterion in the problem of supersonic airflow past a cylinder with a frontal high-porosity cellular insert.

scholarly journals Analysis of a flat capillary evaporator with a bi-layered porous wick

2020 ◽  
Vol 24 (3 Part B) ◽  
pp. 1951-1962
Author(s):  
Paulo Santos ◽  
Thiago Alves ◽  
Amir Oliveira ◽  
Edson Bazzo
Keyword(s):  
Pore Radius ◽  
Thermal Control ◽  
Working Fluid ◽  
Predictive Tool ◽  
Average Pore ◽  
Average Pore Radius ◽  
Porous Wick ◽  
Liquid Feeding ◽  
Design Variables ◽  
Mass And Heat Transfer

A numerical evaluation of the heat and mass transfer concerning a flat capillary evaporator provided by a bi-layered porous wick is presented. The wick has a shape of a flat disc and is assembled between the liquid feeding channel and the vapor chamber. An external heat input is applied into the upper surface of the bi-layered wick, where the working fluid evaporates. The mass and heat transfer are modeled using the mass and energy conservation equations. The model allows to verify the effect of design variables, such as working fluids, dimensions, permeability, average pore radius and thermal conductivity of the wick, in the performance of the capillary evaporator. It can be used as a predictive tool to design similar capillary pumping systems for thermal control of satellite or electronics systems in general.

Estimation of Elastic Constants of Restoration Mortars, Used on Historic Masonries Restoration Interventions, VIA Ultrasonic Technique and Correlation to their Mechanical and Microstructure Parameters

2004 ◽  
Vol 852 ◽  
Author(s):  
Antonia Moropoulou ◽  
Asterios Bakolas ◽  
Eleni Aggelakopoulou ◽  
Anastasia Odatzidou ◽  
Christos Teas ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Modulus Of Elasticity ◽  
Dynamic Modulus ◽  
Pore Radius ◽  
Capillary Rise ◽  
Microstructural Characteristics ◽  
Average Pore ◽  
Average Pore Radius ◽  
Cumulative Volume

ABSTRACTEight syntheses of mortars used for restoration interventions in historic masonry were produced using the traditional materials of aerial lime and artificial pozzolanic additives. The mortars were aged over a 15-month period and then tested for properties related to chemical and mechanical stabilization using the following four analytical techniques: ultrasonic velocity propagation and the mortars' dynamic modulus of elasticity (Ed), mercury intrusion porosimetry for evaluation of microstructural characteristics (percentage open porosity, bulk density, average pore radius, total cumulative volume, and specific surface area), water capillary rise tests for the determination of total cumulative volume accessible to water and capillary rise coefficients of the mortars, and conventional mechanical tests for the determination of the mortars' flexural and compressive strength. Performance is correlated to the mortars' chemical composition, microstructural characteristics (as measure by average pore radius) and mechanical characteristics as measured by dynamic modulus of elasticity (Ed) and flexural and compressive strength (Fc).

Impact of guidelines on antibiotic prescribing approach in primary care—a 10-year study

2020 ◽  
Author(s):  
Nives Radošević Quadranti ◽  
Vera Vlahović-Palčevski ◽  
Branislava Popović ◽  
Ines Diminić-Lisica
Keyword(s):  
Antimicrobial Drug ◽  
Antibiotic Prescribing ◽  
Diagnostic Uncertainty ◽  
Before And After ◽  
Prescribing Behaviour ◽  
Decision Making Processes ◽  
General Data ◽  
The Right ◽  
Structured Questionnaire

Abstract Background Publication and implementation of clinical guidelines is an important educational measure that considerably helps physicians in choosing appropriate antimicrobial drug. Objectives To evaluate long-term changes in antimicrobial prescribing habits before and after publishing the guidelines and to determine the factors that influence physician’s decision to prescribe an antimicrobial drug. Methods The study among general practitioners in Primorsko-Goranska County was conducted in three periods (January 2009, January 2011 and April 2019) by using a structured questionnaire that included general data about the physician, questions about their habits in antibiotic prescribing, criteria that influenced decision to prescribe antibiotics and antimicrobial agent(s) preferred in treating common infections. Results Concomitant chronic (non-pulmonary) disease was the most important factor influencing decision to prescribe an antimicrobial drug. Over 88% of physicians that completed the survey declared themselves as rational prescribers of antimicrobials but more than half of them (53.3%) sometimes prescribed an antibiotic even though it was not indicated compared to 75% of self-reported non-rational prescribers (P ˂ 0.05). Self-reported adherence to the guidelines increased from 34.6% in 2011 to 51.8% in 2019. Conclusion The research showed improvement in physicians’ knowledge in choosing the right antibiotic based on the analysis of answers but indicated the necessity for improving communication skills and empowering physicians not to prescribe antibiotics ‘just in case’ because of diagnostic uncertainty or patient demand. Further qualitative research is needed to understand physicians’ prescribing behaviour and decision-making processes in order to develop interventions that will effectively improve the use of antibiotics.

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