Investigation on the effect of CuO nanoparticles on the IFT and wettability alteration at the presence of [C12mim][Cl] during enhanced oil recovery processes

In the current study, the effect of CuO nanoparticles (CuO-NPs) at the presence of dodecyl-3-methylimidazolium chloride ([C12mim][Cl]) is investigated on the interfacial tension (IFT) reduction, wettability alteration, and even tertiary oil recovery. Since the prepared solutions with CuO-NPs are completely dark and it is impossible to measure the IFT of these solutions in the presence of crude oil using the pendant drop method (since one of the phases must be transparent for IFT measurement using the pendant drop method), n-heptane (representative of saturates) and toluene (representative of aromatics) are used only for IFT measurement of solutions prepared by CuO-NPs, while rest of the experiments are performed using crude oil. The obtained results reveal that CuO-NPs are not stable in the aqueous solution in the absence of surfactant which means fast precipitation of CuO-NPs and a high risk of pore plugging. In this way, the stability of CuO-NPs is investigated at the presence of dodecyl-3-methyl imidazolium chloride ([C12mim][Cl]) as an effective surfactant for stabilizing the CuO-NPs in the aqueous solution (more than 1 month without precipitation using 1000 ppm of IL). Further measurements reveal that although the presence of IL in the aqueous solution can reduce the IFT of oil/aqueous solution system, especially for the aqueous solutions prepared by formation brine (0.65 mN.m−1), the presence of CuO-NPs has no considerable effect on the IFT. On the other hand, not only the contact angle (CA) measurements reveal the considerable effect of IL on the wettability alteration toward water-wet condition (68.3° for IL concentration of 1000 ppm) but also the addition of CuO-NPs can significantly boost the wettability alteration toward strongly water-wet condition (23.4° for the concentration of 1000 ppm of CuO-NPs). Finally, several core flooding experiments are performed using different combinations of chemicals to find the effect of these chemicals on the tertiary oil recovery factor. The results reveal that the presence of CuO-NPs can enhance the oil recovery of injected chemical slug (aqueous solution prepared by dissolution of IL with an oil recovery factor of 10.1% based on Original oil in place (OOIP)) to 13.8, %, 16.9%, and 21.2% based on OOIP if 500, 1000, 2000 ppm of CuO-NPs existed in the solution concomitant with 1000 ppm of [C12mim][Cl].

Obtaining and plasma-electrolyte modification of fibers of ultralight magnesium alloy

The results of researches for the transformation to fiber state the Mg-8Li-1Al-0.6Ce-0.3Y ultralight magnesium alloy by the Pendant Drop Melt Extraction (PDME), and subsequent modifying obtained fibers by Plasma-Electrolytic Treatment (PET) are presented. The results demonstrate possibility of successful application of the above-mentioned methods in relation to chemically active materials. Purposeful modifying of ultralight magnesium alloys by PDME and PET methods is capable to significantly expand areas of using to these materials.

Automated determination of interfacial tension and contact angle using computer vision for oil field applications

Contact angle and surface tension are the two most widely used surface analysis approaches for reservoir fluid characterization in petroleum industries. The pendant drop method has among the most widely used techniques for the estimation of surface tension. The present work utilizes a python-based computer program to automatically determine interfacial tension (IFT) and contact angle from the pendant drop image acquired from a typical pendant drop apparatus. The proposed program uses python-based image processing libraries for the analysis of the pendant drop image. Also, the program is tested on images acquired from the standard solutions for the IFT and contact angle calculation showing promising results with a standard deviation of less than 1.7 mN/m.

Vapor-liquid interfacial properties of the system cyclohexane + CO2: Experiments, molecular simulation and density gradient theory

Properties of the vapor-liquid interface of the binary mixture cyclohexane + CO2 as well as for the two pure substances are reported. The data were obtained from pendant drop experiments (Exp), molecular dynamics (MD) simulation, and density gradient theory (DGT) in combination with the PCP-SAFT equation of state. The following interfacial properties were studied: surface tension (Exp, MD, DGT), relative adsorption (Exp, MD, DGT), enrichment (MD, DGT), and interfacial thickness (MD, DGT). The measurements were carried out at temperatures between 303.15 K and 373.15 K and pressures up to 6 MPa. Furthermore, bulk VLE properties were computed by MD and PCP-SAFT and compared to experimental data from the literature. Data from experiment, MD, and DGT were found to be in good agreement throughout.

Acoustic Characterization Of Sudan Black Nanobubbles For Multimodal Ultrasound & Photoacoustic Imaging

Dyed, shelled, nanobubbles (NBs) have recently been proposed as contrast agents for multimodal ultrasound-photoacoustic (US-PA) imaging. However, changes to the shell composition due to the presence of the dye can modify the response of bubbles to ultrasound. In this work, the effects of the dye, Sudan Black B, on a formulation of lipid shelled NBs are studied. Formulations were produced with increasing concentration of Sudan Black B. The size and concentration of activated NBs were tested. The surface tension of bulk lipid solution was measured using pendant drop tensiometry and activated bubble solutions were measured for single bubble and bubble population response to incident ultrasound. While results show no statistically significant effect of Sudan Black concentration on bubble concentration or size, surface tension increased linearly with dye concentration to a maximum increase of 13%. With the addition of Sudan Black B, single bubble experiments show an increase in the contribution of bubble growth signals, a decrease in contribution of nonlinear signals, and a decrease in bubble destruction. The results presented in this work indicate that the presence of Sudan Black B in the lipid shell of a nanobubble may increase the shell permeability impacting stability of the bubble population and their potential for multimodal US-PA imaging.

In-situ hydrogen wettability characterisation for Underground Hydrogen Storage

Hydrogen storage in subsurface aquifers or depleted gas reservoirs represents a viable seasonal and/or long-term energy storage solution. However, currently, there is a scarcity of subsurface petrophysical data for the hydrogen system, limiting modelling work and industrial rollout. In this work, we address the knowledge gap by determining the wettability and Interfacial Tension (IFT) of the hydrogen-brine-quartz system using a multi-modal, in-situ approach. We utilise the captive bubble, pendant drop and in-situ 3D micro-Computed Tomography (CT) methods to rigorously characterise a hydrogen-brine-Bentheimer rock system, applicable to high quartz sandstone storage systems generally. The captive bubble method determined the effective contact angle ranged between 29°-39° for pressures 6.89-20.68MPa and salinities from distilled water to 5000ppm NaCl brine. In-situ methods confirmed the water-wet system with the mean of the macroscopic and apparent contact angle distributions being 39.77° and 59.75° respectively. Further confirmation of the water-wet system was provided by curvature analysis of fluid clusters. The pendant drop method determined that IFT decreased with increasing pressure in distilled water from 72.45 mN/m at 6.89MPa to 69.43 mN/m at 20.68MPa. No correlation was found between IFT and salinity for the 1000ppm and 5000ppm brines. Our fundamental studies provide insights into the physics of hydrogen wetting in multiphase environments of subsurface reservoirs. With this, we can make informed estimates of relative permeability and capillary pressure for the hydrogen-brine system to model the storage capacity and withdrawal rate of hydrogen in target reservoirs.

Aspects of Coatings on Buckypaper as a Study into the Expected Effects of Coatings on Carbon Nanotube Wires

Buckypaper (BP) was used as an accumulation of nanotubes to simulate as carbon nanotube (CNT) wires to study the interaction between four different insulating coating materials and CNTs. The wettability and electrical conductivity performance of each CNT/coating pair was assessed. The BP was prepared by filtering a sonicated solution of single-walled carbon nanotubes and N,N-Dimethylformamide, through a polytetrafluoroethylene (PTFE) membrane of 0.45 µm pore size. It was observed with Scanning Electron Microscopy, its chemical composition determined by X-ray Photoelectron Spectroscopy, its imperfections and purity measured by Raman Spectroscopy and the porosity (%) and pore distribution obtained by Nitrogen Physisorption. The results showed similar porosity and surface structure to that of reported CNT wires. The surface free energy of the BP was obtained through the Owens-Wendt method, and surface tension of the coatings was calculated with pendant drop measurements to find the adhesion and wettability parameters. Epoxy resin showed the highest wettability and adhesion, which resulted in infiltration into the BP that decreased electrical conductivity by 65%. In contrast, the insulating varnish showed much lower level of wettability and adhesion which resulted in the lowest decrease in conductivity (9.3%).