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A Comprehensive Investigation of Nanocomposite Polymer Flooding at Reservoir Conditions: New Insights into Enhanced Oil Recovery
Recently, the polymer-nanoparticle combination has garnered significant interest in enhanced oil recovery (EOR) due to its promising experimental results. However, the previous research was mostly directed at silica, while alumina and zirconia nanoparticles have gotten the least consideration. Unlike previous works, this study aims to investigate the influence of three NPs: Silica (SiO2), Alumina (Al2O3), and Zirconia (ZrO2) on hydrolyzed polyacrylamide (HPAM). To this end, three nanocomposites were formulated: HPAM-SiO2, HPAM-Al2O3, and HPAM-ZrO2. Rheological evaluations were performed to examine the viscosity degradation of the three nanocomposites and HPAM under reservoir conditions. Furthermore, interfacial tension (IFT) at the oil–water interface and wettability studies were investigated. Moreover, sand-pack flooding was performed to examine the incremental oil recovery. The results revealed that the polymer viscosity was boosted by 110%, 45%, and 12% for HPAM-SiO2, HPAM-Al2O3, and HPAM-ZrO2 respectively under the investigation range of temperature. Moreover, the polymer viscosity was improved by 73%, 48%, and 12% for HPAM-SiO2, HPAM-Al2O3, and HPAM-ZrO2 respectively under the investigation range of salinity. Nanocomposites are also found to be a remarkable agent for reducing interfacial tension and changing the contact angle. The flooding experiments confirmed that the EOR by HPAM, HPAM-SiO2, HPAM-Al2O3, and HPAM-ZrO2, was 8.6%, 17.4%, 15.3%, and 13.6% of OOIP respectively. Moreover, the results of flooding experiments were well validated and matched by numerical simulation. Such findings of this work afford new insights into EOR and reinforce the promising outlook of such technique at the field scale.
Journal Article
Structural design and performance analysis of external gear pump for high viscosity polymer pumping
High-viscosity gear pumps are key equipment for transporting highly viscous polymer media, and their performance is significantly influenced by the coupling effect of medium viscosity and operational parameters. To address the issues of low pumping efficiency and insufficient equipment stability in the preparation process of aerospace composite materials, this study analyzes the fluid pumping characteristics of composites and the gear pump structure under high-viscosity conditions. A universal high-viscosity external gear pump suitable for GNP2200 aerospace composite preparation was designed, with design calculations performed on the core structure to determine key parameters. Experimental tests were conducted to evaluate the pump’s power under varying rotational speeds and medium viscosities. Theoretical calculations and simulation comparisons of the rotational speed were carried out across three viscosity ranges. In addition, volumetric efficiency, energy efficiency, and overall efficiency were computed based on actual working conditions, and the relationship between the dynamic viscosity of the medium and efficiency was analyzed via simulation to comprehensively evaluate the pump’s performance. The results indicate that the pumping capacity is closely related to medium viscosity, and the consistency between simulation and theoretical results validates the rationality of the structural design. When the dynamic viscosity is below 5000 cP, the pump achieves a maximum no-load efficiency of 98.5% and a minimum of 87.0%. Maintaining the speed within the range of 65–90 r/min leads to higher pumping efficiency, extended service life, and improved operational performance. This study provides theoretical and practical insights for the optimized design of high-viscosity gear pumps.
Journal Article
Numerical Simulation of the Rheological Behavior of Nanoparticulate Suspensions
Nanoparticles significantly alter the rheological properties of a polymer or monomeric resin with major effect on the further processing of the materials. In this matter, especially the influence of particle material and disperse properties on the viscosity is not yet understood fully, but can only be modelled to some extent empirically after extensive experimental effort. In this paper, a numerical study on an uncured monomeric epoxy resin, which is filled with boehmite nanoparticles, is presented to elucidate the working principles, which govern the rheological behavior of nanoparticulate suspensions and to simulate the suspension viscosity based on assessable material and system properties. To account for the effect of particle surface forces and hydrodynamic interactions on the rheological behavior, a resolved CFD is coupled with DEM. It can be shown that the particle interactions caused by surface forces induce velocity differences between the particles and their surrounding fluid, which result in increased drag forces and cause the additional energy dissipation during shearing. The paper points out the limits of the used simulation method and presents a correction technique with respect to the Péclet number, which broadens the range of applicability. Valuable information is gained for a future mechanistic modelling of nanoparticulate suspension viscosity by elucidating the interdependency between surface forces, shear rate and resulting drag forces on the particles.
Journal Article
Laboratory Investigation of Nanofluid-Assisted Polymer Flooding in Carbonate Reservoirs
In the petroleum industry, the remaining oil is often extracted using conventional chemical enhanced oil recovery (EOR) techniques, such as polymer flooding. Nanoparticles have also greatly aided EOR, with benefits like wettability alteration and improvements in fluid properties that lead to better oil mobility. However, silica nanoparticles combined with polymers like hydrolyzed polyacrylamide (HPAM) improve polymer flooding performance with better mobility control. The oil displacement and the interaction between the rock and polymer solution are both influenced by this hybrid approach. In this study, we investigated the effectiveness of the injection of nanofluid-polymer as an EOR approach. It has been observed that nanoparticles can change rock wettability, increase polymer viscosity, and decrease polymer retention in carbonate rock. The optimum concentrations for hydrolyzed polyacrylamide (2000 ppm) and 0.1 wt% (1000 ppm) silica nanoparticles were determined through rheology experiments and contact angle measurements. The results of the contact angle measurements revealed that 0.1 wt% silica nanofluid alters the contact angle by 45.6°. The nano-silica/polymer solution resulted in a higher viscosity than the pure polymer solution as measured by rheology experiments. A series of flooding experiments were conducted on oil-wet carbonate core samples in tertiary recovery mode. The maximum incremental oil recovery of 26.88% was obtained by injecting silica nanofluid followed by a nanofluid-assisted polymer solution as an EOR technique. The application of this research will provide new opportunities for hybrid EOR techniques in maximizing oil production from depleted high-temperature and high-salinity carbonate reservoirs.
Journal Article
Wrapper-based feature selection using regression trees to predict intrinsic viscosity of polymer
This paper introduces different types of regression trees for viscosity property forecasting in polymer solutions. Although regression trees have been extensively used in other fields, they do not have been explored to predict the viscosity. One key issue in the context of materials science is to determine a priori which characteristics must be included to describe the prediction model due to a large number of molecular descriptors is obtained. To deal with this, we propose a wrapper method to select the features based on regression trees. Thus, we use regression trees to evaluate different subsets of attributes and build a model from the subset of features that achieved the minimum error. In particular, the performance of eight regression tree algorithms, including both linear and non-linear models, is evaluated and compared to other forecasting approaches using a dataset composed of 64 polymers and 2962 molecular descriptors. The results show that regression trees with nearest neighbors based local models in leaves predict with high accuracy. Moreover, results have been compared to other forecasting approaches such as multivariate linear regression, neural networks and support vector machines showing remarkable improvements in terms of accuracy.
Journal Article
Effect of perforation shear on viscosity of polymer solution
Polymer flooding is a tertiary oil recovery technology that is very suitable for the characteristics of China’s reservoirs. However, due to the fast flow rate of polymer solution in near-well zone, the shear effect of perforation blasthole and the compacted zone results in serious loss of polymer viscosity. In this paper, the polymer used in Dagang Oilfield is studied by simulation experiment through the shearing process of perforating holes, and the influence of different perforating parameters on polymer viscosity loss is analyzed, so as to provide theoretical basis for the optimization design of perforating technology in field test. The experimental results show that, the shear effect of perforation blasthole on polymer is not obvious, and the viscosity retention rate of polymer solution is greater than 96%. The size and shape of perforation blasthole have no effect on viscosity loss of polymer solution. The shear effect of compacted zone on polymer is obvious, and the viscosity retention rate of polymer solution is lower than 64% for the target block. The viscosity loss of polymer solution increases with flow rate at compacted zone, and the decrease of permeability can increase viscosity loss of polymer solution. The higher the polymer concentration is, the stronger the shear resistance is, while the higher the molecular weight is, the weaker the shear resistance is. It is suggested that perforation gun and perforation method with deep perforation depth and low compaction degree be chosen to reduce the flow rate at compacted zone and viscosity loss of polymer solution.
Journal Article
Polymer viscoelasticity : basics, molecular theories, experiments and simulations
This book covers in great detail the Rouse-segment-based molecular theories in polymer viscoelasticity - the Rouse theory and the extended reptation theory (based on the framework of the Doi-Edwards theory) - that have been shown to explain experimental results in a consistently quantitative way. The explanation for the 3.4 power law of viscosity, quantitative line-shape analyses of viscoelastic responses and agreements between different sorts of viscoelastic responses, the consistency between the viscoelasticity and diffusion results, the clarification of the onset of entangelement, the discovery of the number of entanglement strands per cubed entanglement distance being a universal constant and the basic mechanism of the glass transition-related thermorheological complexity are discussed or shown in great detail. The mystery behind the success of the Rouse-segment-based molecular theories over the entropic region of a viscoelastic response is revealed by the Monte Carlo simulations on the Fraenkel chains. Specifically, the simulation studies give a natural explanation for the coexistence of the energy-driven and entropy-driven modes in a viscoelastic response and provide a theoretical basis resolving the paradox that the experimentally determined sizes of Rouse and Kuhn segments are nearly the same. This book starts from a very fundamental level; each chapter is built upon the contents of the previous chapters. Thus, the readers may use the book as a textbook and eventually reach an advanced research level. This book is also a useful source of reference for physicists, chemists and material scientists.
eBook
Development of Rizatriptan Mouth Dissolving Films: A Fast Absorbing Drug Delivery System for Effective Treatment of Migraine
[...]the development of novel dosage forms as alternative to conventional solid orals may address the issues of low bioavailability and patient compliance. [...]the MDFs obtained will be uniform in film properties like thickness, content uniformity along with good mechanical properties. [...]no works were reported so far on the influence of formulation variables such as plasticizers, film thickness and polymer viscosities on mechanical, chemical and drug release properties of MDFs. [...]the present investigation was undertaken to prepare RIZ MDFs using wet film applicator and evaluate them for the effect of various formulation variables on physico-mechanical, chemical and drug release properties. 2.MATERIALS AND METHODS: 2.1. Whereas, MDFs prepared with HPMC polymers were transparent with quick drying rates and good mechanical properties. [...]HPMC polymers with three different viscosity grades (E3, E5 and E15) were selected for preparation of RIZ MDFs.
Journal Article
Discussion on setting shear coefficient of viscous concentration parameter in numerical simulation of chemical flooding
Chemeor software is the only application of chemical flooding analog and digital simulation software in our factory at present. Viscosity parameter is the most important parameter affecting water cut and ultimate recovery in software. The polymer viscosity at zero shear rate is used in calculating viscous concentration parameters. Usually, after artificial shearing, the viscosity parameters of polymer are estimated, which are in accordance with the actual production. Because it is impossible to give a more accurate shear coefficient, Often, the initial calculated viscosity is quite different from the actual one. It has caused great difficulties for subsequent adjustment. In this paper, the shear behavior under different injection systems is discussed. Finally, the optimum initial operating viscosity shear coefficient is determined.
Journal Article