Effect of alcohol-treated CO2 on interfacial tension between CO2 and oil, and oil swelling

This paper investigates the extent to which alcohol-treated carbon dioxide (CO2 ), a mixture of alcohol and CO2 equilibrated at experimental pressure and temperature, can lead to greater interfacial tension reduction and greater oil swelling than can pure CO2 . Experimental measurements of interfacial tension and swelling behavior are made using a high-pressure, high-temperature visual cell at 70 °C. Two sets of fluid pairs are used: pure CO2 and oil, and alcohol-treated CO2 and oil. Two types of oil are used: a mixture of 35% hexane and 65% decane (C6 -C10 mixture), and pure decane (pure C10 ). Ethanol and methanol are used to prepare alcohol-treated CO2 . Numerical simulations are used to estimate a reduction in the minimum miscibility pressure when using alcohol-treated CO2 . Interfacial tension between alcohol-treated CO2 and oil is found to be 0.02 to 2.2 mN/m less than that between pure CO2 and oil. Simulation results suggest that alcohol-treated CO2 yields 0.2 to 1.2 MPa lower minimum miscibility pressure compared to pure CO2 . Alcohol-treated CO2 also is found to cause 6% to 43% more swelling of oil than does pure CO2 . Interfacial tension and swelling results suggest that alcohol-treated CO2 yields better miscibility with oil compared to pure CO2 .Cited as: Saira, Yin, H., Le-Hussain, F. Effect of alcohol-treated CO2 on interfacial tension between CO2 and oil, and oil swelling. Advances in Geo-Energy Research, 2021, 5(4): 407-421, doi: 10.46690/ager.2021.04.0

The impact of wettability and fluid saturations on multiphase representative elementary volume estimations of micro-porous media

The occurrence of multi-phase flows in porous media is a complex phenomenon that involves multiple scales, ranging from individual pores to larger continuum scales. Upscaling frameworks have emerged as a response to the need for addressing the disparity between micro-scale processes and macroscopic modelling. Determination of the representative elementary volume is important for understanding fluid dynamics in micro-porous materials. The size of the representative elementary volume for multiphase flow in porous media is significantly affected by wettability and fluid saturations. Previous studies have overlooked this aspect by conducting simulations under conditions of constant medium wettability and fluid saturations. This study uses finite volume simulations with a volume of fluid approach for two distinct asymptotic homogenization methods, namely hydrodynamic bounds of relative permeability and thermodynamic bounds of entropy production. Strong wetting conditions with high wetting phase saturation were found to require a smaller sample size to establish representative elementary volume, while mixed-wettability scenarios necessitate the largest sample sizes. These findings improve our understanding of multiphase fluid flow behaviour in micro-porous materials and aid in enhancing techniques for scaling up observations and predictive modelling in engineering and environmental fields.Document Type: Short communicationCited as: Hussain, S. T., Regenauer-Lieb, K., Zhuravljov, A., Hussain, F., Rahman, S. S. The impact of wettability and fluid saturations on multiphase representative elementary volume estimations of micro-porous media. Capillarity, 2023, 9(1): 1-8. https://doi.org/10.46690/capi.2023.10.0

Effect of fines migration on oil recovery from carbonate rocks

We perform single-phase and two-phase flooding on Edwards Brown rock samples. The single-phase injection was of seawater or CaCl2 brine, at successive salinities 0.63, 0.21, 0.07, 0.05, and 0 mol/L (distilled water). For CaCl2 brine experimental run, no significant fines migration or permeability decrease is observed. For seawater experimental run, distilled water injection is found to bring about the highest concentration of produced fines and most of the permeability decrease, with the ultimate permeability decrease being 99.94%. Therefore, distilled water injection is used to stimulate fines migration in the following two-phase experimental runs. Two-phase experiments are performed on four Edwards Brown rock samples using seawater or CaCl2 brine as the aqueous phase, and Soltrol® 130 or crude oil as the oleic phase. Rock samples are initially fully saturated with 0.63 mol/L of the selected aqueous solution. This is followed by injecting the selected oil at a constant rate for at least 20 pore volumes to displace brine. Next, selected brine is injected to displace oil, and finally distilled water. For CaCl2 brine, distilled water injection is found to recover no additional oil of either type of oil. However, for seawater, the fines production observed during distilled water injection is found to reduce water relative permeability by two orders of magnitude when Soltrol® 130 is used and by three orders of magnitude when crude oil is used. The seawater experimental runs also brought about additional oil recovery during distilled water injection: 18% when Soltrol® 130 is used and 3.4% when crude oil is used. This last result can be attributed to the plugging of pores due to fines migration, which can divert further injected water into previously unswept pores. Cited as: Almutairi, A., Saira, S., Wang, Y., Le-Hussain, F. Effect of fines migration on oil recovery from carbonate rocks. Advances in Geo-Energy Research, 2023, 8(1): 61-70. https://doi.org/10.46690/ager.2023.04.0

Asymptotic hydrodynamic homogenization and thermodynamic bounds for upscaling multiphase flow in porous media

This paper presents a novel technique for upscaling multiphase fluid flow in complex porous materials that combines asymptotic homogenization approach with hydrodynamicand thermodynamic bounds. Computational asymptotic homogenization has been widely utilised in solid mechanics as a method for analysing multiscale expansion and convergence coefficients in heterogeneous systems. Computations are performed over several volumes by increasing the size until convergence of the material parameters under different load scenarios is achieved. It works by simplifying the problem with a homogenization method and is ideally suited for estimating the representative elementary volume of microporous material by expanding algorithms. The validity of the method to include complex multiphase hydrodynamic processes and their interaction with the matrix structure of porous media lacks a sound theoretical foundation. To overcome this problem, a variational thermodynamic approach is used. Upper and lower bounds of entropy production are proposed to provide effective material properties with uncertainties. This allows multiple possibilities to address dynamics via thermodynamically linked processes. This work utilizes volume of fluid approach to model multiphase porous media flow in models based on micro-computerized tomography x-ray data of Bentheimer sandstone and Savonnieres carbonate. It is found that the representative elementary volume sizes obtained by the conventional asymptotic homogenization methods do not satisfy thermodynamic bounds which consistently require larger representative elementary volume sizes. For the Savonnieres carbonate the entropic bounds have not converged fully questioning the reliability of the effective properties obtained from the classical method.Document Type: Original articleCited as: Hussain, S. T., Regenauer-Lieb, K., Zhuravljov, A., Hussain, F., Rahman, S. S. Asymptotic hydrodynamic homogenization and thermodynamic bounds for upscaling multiphase flow in porous media. Advances in Geo-Energy Research, 2023, 9(1): 38-53. https://doi.org/10.46690/ager.2023.07.0

Adsorption/desorption characteristics for methane, nitrogen and carbon dioxide of coal samples from Southeast Qinshui Basin, China

This paper presents an experimental and modelling study of the adsorption/desorption of pure gases CH4, CO and N and their binary and ternary mixtures on coal samples obtained from southeast Qinshui Basin, China. Results show that the adsorbed amounts of N, CH4 and CO have approximate ratios of 1.0:1.3:2.4, respectively. No significant hysteresis from adsorption to desorption is observed for pure N and CH4 whereas significant hysteresis is measured for CO in CO -CH4 and CO-CH4-N mixtures and CH4 in the N -CH4 mixture. The experimental observations are modelled using three different models, namely the extended Langmuir (EL), the Langmuir-based ideal adsorbed solution (L-IAS) and the Dubinlin- Radushkevich-based ideal adsorbed solution (D-R-IAS). The models predict well the experimental observations for desorption tests. But the measurements for the low adsorbate capacity in binary and ternary mixtures are overestimated by the prediction models. It is found that the EL model predicts the CO -CH4 desorption test better while the D-R-IAS model is the best model for the CO-CH4- N adsorption

Passive cooling analysis of an electronic chipset using nanoparticles and metal-foam composite PCM: An experimental study

Thermal management of electronic components is critical for long-term reliability and continuous operation, as the over-heating of electronic equipment leads to decrement in performance. The novelty of the current experimental study is to investigate the passive cooling of electronic equipment, by using nano-enriched phase change material (NEPCM) with copper foam having porosity of 97 %. The phase change material of PT-58 was used with graphene nanoplatelets (GNPs) and magnesium oxide (MgO) nanoparticles (NPs), having concentrations of 0.01 wt. % and 0.02 wt. %. Three power levels of 8 W, 16 W, and 24 W, with corresponding heating inputs of 0.77 kW/ m2, 1.54 kW/ m2 and 2.3 kW/ m2, respectively, were used to simulate the heating input to heat sink for thermal characterization. According to results, at 0.77 kW/ m2 heating input the maximum base temperature declined by 13.03 % in 0.02 wt. % GNPs-NEPCM/copper foam case. At heating input of 1.54 kW/ m2, the maximum base temperature reduction of 16 % was observed in case of 0.02 wt. % GNPs-NEPCM/copper foam and 13.1 % in case of 0.02 wt. % MgO-NEPCM/copper foam. Similarly, at heating input of 2.3 kW/ m2, the maximum temperature of base lessened by 12.58 % in case of 0.02 wt. % GNPs-NEPCM/copper foam. The highest time to reach the set point temperature of 50 ⁰ C, 60 ⁰ C, and 70 ⁰ C was in case of GNPs-NEPCM/copper foam composites, while at all power levels MgO-NEPCM/copper foam gave comparable performance to GNPs based composite. Similar trend was observed in the study of enhancement ratio in operation time. From the results, it is concluded that the copper foam incorporation in NEPCM is an effective measure to mitigate the heat sink base temperature and can provide best cooling efficiency at low and higher heating loads

Physicians’ Understanding and Practices of Pharmacovigilance Qualitative Experience from a Lower Middle-Income Country

Developed countries have established pharmacovigilance systems to monitor the safety of medicines. However, in the developing world, drug monitoring and reporting are facing enormous challenges. The current study was designed to explore the challenges related to the understanding and practices of physicians in reporting adverse drug reactions in Lahore, Pakistan. Through the purposive sampling technique, 13 physicians were interviewed. All interviews were audio-recorded, transcribed verbatim, and analyzed for a thematic content analysis. The thematic content analysis yielded six major themes: (1) Familiarity with medication safety and adverse drug reaction (ADR) concept, (2) Knowledge about pharmacovigilance activities, (3) Practices related to ADR reporting, (4) Barriers impeding ADR reporting, (5) Acknowledgement of the pharmacist’s role, and (6) System change needs. The majority of the physicians were unaware of the ADR reporting system; however, they were ready to accept practice changes if provided with the required skills and training. A lack of knowledge, time, and interest, a fear of legal liability, poor training, inadequate physicians’ and other healthcare professionals’ communication, and most importantly lack of a proper reporting system were reported as barriers. The findings based on emerging themes can be used to establish an e�ective pharmacovigilance system in Pakistan. Overall, physicians reported a positive attitude towards practice changes, provided the concerned authorities support and take interest in this poorly acknowledged but most needed component of the healthcare system

Insights, Trends and Challenges Associated with Measuring Coal Relative Permeability

Due to the poroelasticity of coal, both porosity and permeability change over the life of the field as pore pressure decreases and effective stress increases. The relative permeability also changes as the effective stress regime shifts from one state to another. This paper examines coal relative permeability trends for changes in effective stress. The unsteady-state technique was used to determine experimental relativepermeability curves, which were then corrected for capillary-end effect through history matching. A modified Brooks-Corey correlation was sufficient for generating relative permeability curves and was successfully used to history match the laboratory data. Analysis of the corrected curves indicate that as effective stress increases, gas relative permeability increases, irreducible water saturation increases and the relative permeability cross-point shifts to the right

Impact of diabetes-related knowledge and medication adherence on quality of life among type 2 diabetes patients in a tertiary health facility in Multan, Pakistan

Purpose: To assess the impact of drug adherence and diabetes-related knowledge on the quality of life (QoL) of type 2 diabetes patients in a hospital in Pakistan.Methods: A cross-sectional study was conducted in City Hospital, Multan, Pakistan between March and September 2020. A total of 151 patients diagnosed with type 2 diabetes mellitus (T2DM) were recruited. Medication adherence, diabetes-related knowledge, and QoL were assessed by Drug attitude inventory-10 (DAI-10), the Michigan Diabetes Knowledge Test (MDKT), and EQ-5D-3L tools, respectively. The association between sociodemographic data and study variables was assessed by independent t-test and one-way ANOVA.Results: Among the 151 patients, 53 % were males. The mean MDKT score was 0.33 ± 0.18, indicating poor knowledge of diabetes. An overall moderate level of adherence was observed among the participants (mean adherence score, 6.14 ± 1.39). Mean QoL score was 1.31 ± 0.28, and the Visual Analog Scale score (VAS) was 59.6 ± 12.21, indicating a good to moderate QoL among the study participants. Study participants with a longer duration of diabetes and poor adherence to their medications showed poor QoL (p = 0.01, p = 0.004 respectively).Conclusion: Overall, the patients reported poor knowledge, moderate adherence, and good to moderate QoL. Moreover, patients with poor adherence to medication, longer duration of diabetes, and poorly controlled HbA1c showed poor QoL

Passive Cooling Analysis of an Electronic Chipset Using Nanoparticles and Metal-Foam Composite PCM: An Experimental Study

Thermal management of electronic components is critical for long-term reliability and continuous operation, as the over-heating of electronic equipment leads to decrement in performance. The novelty of the current experimental study is to investigate the passive cooling of electronic equipment, by using nano-enriched phase change material (NEPCM) with copper foam having porosity of 97. The phase change material of PT-58 was used with graphene nanoplatelets (GNPs) and magnesium oxide (MgO) nanoparticles (NPs), having concentrations of 0.01 wt. and 0.02 wt.. Three power levels of 8 W, 16 W, and 24 W, with corresponding heating inputs of 0.77 kW/m2, 1.54 kW/m2 and 2.3 kW/m2, respectively, were used to simulate the heating input to heat sink for thermal characterization. According to results, at 0.77 kW/m2 heating input the maximum base temperature declined by 13.03 in 0.02 wt. GNPs-NEPCM/copper foam case. At heating input of 1.54 kW/m2, the maximum base temperature reduction of 16 was observed in case of 0.02 wt. GNPs-NEPCM/copper foam and 13.1 in case of 0.02 wt. MgO-NEPCM/copper foam. Similarly, at heating input of 2.3 kW/m2, the maximum temperature of base lessened by 12.58 in case of 0.02 wt. GNPs-NEPCM/copper foam. The highest time to reach the set point temperature of 50 °C, 60 °C, and 70 °C was in case of GNPs-NEPCM/copper foam composites, while at all power levels MgO-NEPCM/copper foam gave comparable performance to GNPs based composite. Similar trend was observed in the study of enhancement ratio in operation time. From the results, it is concluded that the copper foam incorporation in NEPCM is an effective measure to mitigate the heat sink base temperature and can provide best cooling efficiency at low and higher heating load