Nuclear Magnetic Resonance Nmr Research Articles

Holistic analysis of glyphosate formulations with nuclear magnetic resonance, similarity calculations and differential NMR

Glyphosate is the most widely used herbicide in the world. Due to varying formulations, common adulteration and illegal trade there is an extreme need to monitor the composition of formulations to ensure the safety. Similarity calculations and differential NMR allowed the assessment of all organic compounds of the mixture, down to the detection limit in the submicrogram range. Glyphosate, isopropylamine and polyoxyethylene tallow amines (POEA) were among the compounds detected together with components classified as impurities such as methanol and acetone. The quantities of the analyzed compounds range from several dozens of milligrams of glyphosate down to submicrogram quantities of methanol and acetone in the NMR tube. Glyphosate was quantified using a fitted calibration curve that in comparison to classic qNMR experiments needed shorter measuring times. Among the co-formulants, the one of greatest environmental interest is polyoxyethylene tallow amine especially because it might be more harmful than glyphosate itself. This work illustrates the value of NMR, with calculation of similarities and differential NMR for the rapid comparison and assessment of samples taking into account major and minor components in the formulations, many of these being industrial secrets.

Assessing the complementarity of time domain NMR, solid-state NMR and dynamic vapor sorption in the characterization of polysaccharide-water interactions

Characterizing the hygroscopic behavior of macromolecular assemblies is crucial for understanding biological processes as well as to develop tailor-made polysaccharides-based products. In this work, assemblies consisting of nanocelluloses (CNC or CNF) and/or glucomannan in different ratio were studied at different water activity levels, using a multi-analytical approach that combined Dynamic Vapor Sorption (DVS), Time-Domain Nuclear Magnetic Resonance (TD-NMR) and solid-state NMR (ss-NMR). The water retention capacity of the films, as a function of their composition, showed that an enrichment in konjac glucomannan in association with cellulose increased the water absorption capacity but decreased the water retention capacity. In addition, the combination of CNC and glucomannan appears to reduce the water absorption capacity of each polymer. Correlating the findings from the various methods allowed us to propose the use of TD-NMR data for predicting the water retention capacity. These results, summarized in a schematic representation, offer new insights into the organization of water molecules in polysaccharide assemblies in various humidity conditions.

The Advantages on Using GGBS and ACBFS Aggregate to Obtain an Ecological Road Concrete

This work aims to show the advantages of using GGBS (Ground Granulated Blast Furnace Slag) and ACBFS aggregate (Air-Cooled Blast Furnace Slag) on the tensile strength and durability properties of infrastructure concrete at the reference age of 28 days. Three concrete mixes were prepared: the first one was a control sample; the second one had 15% GGBS (instead of Portland cement) and 25% ACBFS (instead of natural sand); and the third had 15% GGBS (instead of Portland cement) and 50% ACBFS (instead of natural sand). The studies on mortars focused on the ratio of compressive strength (CS) in correlation with the specific surface area (obtained by the Blain method). The microstructure of the prepared mortars was examined at the age of 28 days by X-ray diffraction, SEM electron microscopy with an energy-dispersive EDX spectrometer, and NMR nuclear magnetic resonance relaxometry. The results of the tests carried out afterwards on the concretes containing slag (15% GGBS and 25% or 50% ACBFS) showed values that met high-quality criteria for exfoliation (S56 < 0.1 kg/m2), carbonation, and gelling G100 (with a loss of resistance to compression η < 25%). The slag concretes showed a degree of gelation of G100 (with a loss of compressive strength below 25%), low volume losses below 18,000 mm3/5000 mm2 (corresponding to wear class 4, grade I), and moderate penetration of chlorine ions (according to the RCPT test). All of these allow the concrete with slag (GGBS/ACBFS) to be recommended as an ecological road concrete. Our study proved that a high-class road concrete of BcR 5.0 can be obtained, with tensile strengths of a minimum 5 MPa at 28 days (the higher road concrete class in Romania, according to national standards).

Estimation of Petrophysical Parameters of Carbonates Based on Well Logs and Laboratory Measurements, a Review

The purpose of this review paper is to show the possibilities of carbonate reservoir characterization using well logging and laboratory measurements. Attention was focused on standard and new methods of well logging acquisition and interpretation including laboratory experiments to show a part of the history of carbonate rock investigations as hydrocarbon or water reservoirs. Brief information on the geology, mineralogy and petrography of carbonate rocks was delivered. Reservoir properties, i.e., porosity (including fracturing), permeability, and saturation, were defined to emphasize the specific features of carbonates, such as fractures, and vugs. Examples of methodologies were selected from the commonly used laboratory techniques (thin sections examination, mercury and helium porosimetry, X-ray diffraction—XRD) combined with the standard well logs (bulk density—RHOB, neutron porosity—NPHI, sonic slowness—DT, and deep resistivity—Rd) to show the methods that have been used since the very beginning of the scientific and engineering studies of carbonates. Novelty in well logging, i.e., resistivity and acoustic imaging, nuclear magnetic resonance–NMR, dipole shear sonic imaging–DSI, and a spectral neutron-gamma log-geochemical device–GLT combined with modern laboratory investigations (NMR laboratory experiments, scanning electron microscopy SEM), showed how continuous information on mineral composition, porosity and saturation could be obtained and juxtaposed with very detailed laboratory data. Computed X-ray tomography (CT) enabling the 2D and 3D analyses of pores and fractures was presented as a quantitative methodology, effective in pore space characterization, revealing rock filtration abilities. Deep learning and artificial intelligence were used for joining various types of data. It was shown that thanks to new computational technologies original data from very small samples (micro scale), extensively describing the flow ability of the reservoir, could be extended to mezzo scale (core samples) and macro scale (well log images). Selected examples from the published papers illustrated the review. References cited in the text, together with the issues included in them, were the rich source of the practical knowledge processed These were checked by the authors and could be used in other projects.

Variable-temperature solid-state NMR analysis of woody materials in the presence of small hydroxyl molecules

Interactions between the hierarchical structure of Japanese cypress and small hydroxylic solvents with high polarity were studied using variable-temperature 13C cross-polarization and magic-angle spinning nuclear magnetic resonance (CP/MAS) NMR spectroscopy, including low-temperature measurements. 13C CP/MAS NMR spectra were enhanced by dipolar interactions closely related to 1H–13C magnetization transfer, providing information about the interaction between woody materials and small hydroxyl molecules. The change in interaction was particularly near the melting point of the hydroxylic solvent, where a decrease in the intensity of the cypress carbohydrate signal and the appearance of the signal of solvent molecules were observed. The trend of signal intensity in the variable-temperature 13C CP/MAS NMR spectra of cypress and cellulose fibers in the presence of hydroxylic solvents indicated that the decrease in the carbohydrate signal intensity due to the transfer of magnetization near the melting point of the hydroxyl molecule is greater when the size of the hydroxyl molecule is smaller. Furthermore, molecular association in the nanopores of the hierarchical structure allowed the hydroxyl molecular signals of the impregnated cypress to appear above the melting point.

Dispersion and weak retardation performance of sulfate-based starch maleic acid monoesters in cement

To reduce the influence of a sulfate-based starch water-reducing agent on the setting time of cement, a novel starch-based water-reducing agent, namely sulfate-based starch maleic acid monoester (SAMAS), was designed to adjust its hydrophilicity by maleic acid monoester. Gel permeation chromatography, Fourier transform infrared spectroscopy, and 1H NMR nuclear magnetic resonance spectroscopy were used to characterize the prepared SAMAS, while Zeta potential, UV–Vis absorption, X-ray photoelectron spectroscopy, X-ray diffraction, cement paste fluidity, and setting time measurements were conducted to investigate its dispersion performance, retardation performance, adsorption behavior, and mechanism of action. SAMAS exhibited good dispersion performance and did not significantly prolong the setting time of the cement. In addition, the dispersion performance of SAMAS was found to depend mainly on steric hindrance, and its weak retardation performance originated from the hydrophilic regulation of the maleic acid monoester groups, which ensures the normal progress of the cement hydration reaction by hindering the formation of a hydration film.

Synthesis, characterization, and corrosion inhibition activity of new imidazo[1.2-a]pyridine chalcones

In this work, two new Imidazo[1.2-a]pyridine chalcones (IMZs) namely, 1-(3-methylpyrazin-2-yl)-3-(2-phenylimidazo[1,2-a]pyridin-3-yl)prop-2-en-1-one (IMZ1) and 3-(2-(4-chlorophenyl)imidazo[1,2-a]pyridin-3-yl)-1-(3-methylpyridin-2-yl)prop-2-en-1-one (IMZ2) were synthesized and characterized by spectroscopic methods namely, High Performance Liquid Chromatography (HPLC) coupled to Mass Spectrometry (MS) and NMR Nuclear Magnetic Resonance (1H and 13C) and investigated as corrosion inhibitors for mild steel (MS). The study included surface morphology, electrochemistry, gravimetric, theoretical, and computational analyses.Electrochemical results (Electrochemical impedance spectroscopy (EIS) and Potentiodynamic polarization (PDP)) demonstrate that IMZs are effective MS inhibitors in 1 M HCl. PDP studies demonstrated Imidazo[1,2-a]pyiridine chalcones at the ideal 1 mM concentration decreased the icorr from 0.948 mA/cm2 (blank) to 0.069 mA/cm2 and 0.051 mA/cm2 for IMZ1 and IMZ2, respectively, with the assistance of a mixed type inhibitor with cathodic predominance. Similarly, the maximal efficiencies of IMZ1 and IMZ2 ligands were 92.43 and 95.40 percent, respectively. Langmuir isotherm and adsorption thermodynamics investigation indicated that the chosen inhibitors adsorb on the metal surface by forming covalent bonds with adsorption constants on the order of 104 M−1. The potential sites for molecule adsorption on the metal surface were identified by theoretical and computational studies, offering new knowledge about the corrosion prevention process.

Characterization of Capecitabine Loaded Stealth Liposomes by Nuclear Magnetic Resonance

Background Liposomes are lipid aggregates with a careful choice of lipid composition and process parameters. Liposomes are formulated by optimization of process parameters of liposomes to achieve desired bioavailability and to improve stability. Objectives The main objective of the present research was to formulate colon targeting capecitabine loaded stealth liposomes characterized by using Nuclear magnetic resonance NMR techniques to determine the fractions of the drug capecitabine CAP encapsulated in the liposomal suspension.Methods Liposome properties were evaluated by NMR. 31P-NMR 31Phosphorus NMR in combination with the use of chemical shift reagents were used for the identification of lamellarity of liposomes which can have a strong effect on both encapsulation efficiency and the efflux rate of encapsulated active compounds.Results The results suggested that capecitabine remained intact during the loading process and the liposomal drug was present in a soluble form. Conclusion 31P-NMR was found to be an effective method to study the lamellarity of liposomes and to determine the distributed fractions of encapsulated capecitabine.

Preparation, characterization, and structural studies of new sodium gallium tungstate phosphate glasses

A new glass forming region in the quaternary system Na2O-P2O5-WO3-Ga2O3 along the composition line (NaPO3)80-x(Ga2O3)20(Na2WO4)x (x = 0, 5, 10, 15, 20 and 25 mol%) has been prepared and characterized by X-ray diffraction, Differential Scanning Calorimetry (DSC), Raman scattering and 31P, 23Na and 71Ga nuclear magnetic single and double resonance NMR techniques. The partial substitution of the NaPO3 component by Na2WO4 produces a significant increase of molar volume (decreased oxygen packing density), whereas the glass transition temperatures Tg pass through a shallow maximum near x = 10 to 15. While in the x = 0 sample the structure is dominated by Q1 units linked to gallium in four-, five- and six-coordination, the gradual substitution of phosphate by tungstate significantly affects network reconstruction, eliminating P-O-P linkages, the concentration of which is found to be greatly diminished above the x = 10 level. While the structure of these glasses is dominated by Q0 units, connected to both gallium and tungstate species, 71Ga{31P} REDOR data suggest significant decreases in the extent of gallium-phosphorus connectivity with increasing Na2WO4 content. Finally, monotonic changes in both 23Na chemical shifts and 23Na-31P second moment values, M2(Na-P), indicate that the anionic surroundings of the sodium ions evolve from a pure phosphate to a mixed phosphate/tungstate environment.

Microstructure, rheological and water mobility behaviour of plant-based protein isolates (pea and quinoa) and locust bean gum mixtures

This work reports the impact of locust bean gum (LBG) in the continuous phase of plant-based proteins, i.e. quinoa protein (QPI) and pea protein isolates (PPI). Experimental measurements such as confocal microscopy, rheological analysis and water mobility via nuclear magnetic resonance (nmr) spin-spin relaxation time (T2) were carried out. The influence of LBG on the rheological properties of QPI and PPI is consistent with an exchange-based nmr interpretation of T2 for biopolymer and water. Addition of LBG increased the viscoelastic properties (storage and loss modulus) and shear viscosities of the mixtures. LBG interacted with both plant proteins, resulting in the formation of more dense protein networks and protein coacervates. A stronger interaction between the PPI and LBG was observed, resulting in higher shear viscosities with lower water mobility as compared to QPI:LBG formulations. Results indicated that the interaction between the protein and polysaccharide played a significant role in the microstructure, its rheological properties and consequently water mobility.

Identifying the structure of a plaster mortar mixtures on the basis of NMR investigations

Starting from the concept of sustainable development, the research program aims to establish a waste management by reducing the construction materials used in the preparation of plaster mortars. Thus, the chosen material, respectively the used paint plays an important role in replacing the main components of the plaster mortar recipe. Following the research in the laboratory of the Faculty of Construction, it was concluded that used paint can replace water or cement in the recipe in different percentages, a fact recorded in an article published in early 2022 [1]. In the future, this research can help reduce the raw materials used to make plaster mortars, an ambitious plan and a step towards the transition to the circular economy. By reducing the amount of raw materials by recycling used paint, we protect the environment. During the investigations, the 3 mortar recipes: CSIV, CSIV10C, CSIV20P are presented from the point of view of nuclear magnetic resonance NMR. According to the research program, the tracking of behavior over time was done by analyzing the samples at 3 days, 7 days and 28 days.

Identification of Linomide Derivatives as Potential Anticancer Therapeutics using Molecular Docking Studies.

12 analogs bearing a structural similarity to Linomide, a bonafide anticancer agent were synthesized wherein cyclization of substituted dianilides rendered 4-hydroxyquinolin-2(1H)-ones that were subjected to a Mannich reaction to yield 4-hydroxy-3-(substituted-1-ylmethyl) quinolin-2(1H)-one analogs. Characterization was performed using IR, 1H nuclear magnetic resonance and 13C NMR spectral analysis. Subsequently, in vitro anticancer studies revealed that Compound 4b showed maximum cytotoxicity with IC50 values of 1.539 μM/ml and 1.732 μM/ml against A549 and K562 cell lines respectively. This, however, is lower in comparison with standard Paclitaxel (IC50 values of 0.3 μM/ml for both cell lines). Surprisingly, docking studies at the active site of EGFRK revealed Compound 4b possessed a MolDock Score of -110.2253 that is highly comparable to the standard 4-anilinoquinazoline (MolDock Score of -112.04). Our computational and biological data thus provides an insight on the cytotoxicity of these derivatives and warrants future research that can possibly lead to the development of potent anticancer therapeutics.

Synthesis, In Silico and Pharmacological Evaluation of New Thiazolidine-4-Carboxylic Acid Derivatives Against Ethanol-Induced Neurodegeneration and Memory Impairment

IntroductionSeveral studies revealed that alcohol utilization impairs memory in adults; however, the underlying mechanism is still unclear. The production of inflammatory markers and reactive oxygen species (ROS) plays a major role in neurodegeneration, which leads to memory impairment. Therefore, targeting neuroinflammation and oxidative distress could be a useful strategy for abrogating the hallmarks of ethanol-induced neurodegeneration. Moreover, several studies have demonstrated multiple biological activities of thiazolidine derivatives including neuroprotection.MethodsIn the current study, we synthesized ten (10) new thiazolidine-4-carboxylic acid derivatives (P1-P10), characterized their synthetic properties using proton nuclear magnetic resonance (1H-NMR) and carbon-13 NMR, and further investigated the neuroprotective potential of these compounds in an ethanol-induced neuroinflammation model.ResultsOur results suggested altered levels of antioxidant enzymes associated with an elevated level of tumor necrosis factor-alpha (TNF-α), nuclear factor-κB (p-NF-κB), pyrin domain-containing protein 3 (NLRP3), and cyclooxygenase-2 (COX-2) in ethanol-treated animals. Ethanol treatment also led to memory impairment in rats, as assessed by behavioral tests. To further support our notion, we performed molecular docking studies, and all synthetic compounds exhibited a good binding affinity with a fair bond formation with selected targets (NF-κB, TLR4, NLRP3, and COX-2).DiscussionOverall, our results revealed that these derivatives may be beneficial in reducing neuroinflammation by acting on different stages of inflammation. Moreover, P8 and P9 treatment attenuated the neuroinflammation, oxidative stress, and memory impairment caused by ethanol.

A machine learning framework for low-field NMR data processing

Low-field (nuclear magnetic resonance) NMR has been widely used in petroleum industry, such as well logging and laboratory rock core analysis. However, the signal-to-noise ratio is low due to the low magnetic field strength of NMR tools and the complex petrophysical properties of detected samples. Suppressing the noise and highlighting the available NMR signals is very important for subsequent data processing. Most denoising methods are normally based on fixed mathematical transformation or hand-design feature selectors to suppress noise characteristics, which may not perform well because of their non-adaptive performance to different noisy signals. In this paper, we proposed a “data processing framework” to improve the quality of low field NMR echo data based on dictionary learning. Dictionary learning is a machine learning method based on redundancy and sparse representation theory. Available information in noisy NMR echo data can be adaptively extracted and reconstructed by dictionary learning. The advantages and application effectiveness of the proposed method were verified with a number of numerical simulations, NMR core data analyses, and NMR logging data processing. The results show that dictionary learning can significantly improve the quality of NMR echo data with high noise level and effectively improve the accuracy and reliability of inversion results. • A “data processing framework” is proposed to improve the quality of low-field NMR echo data. • Dictionary learning is employed for adaptive dictionary construction and available signal characteristics extraction for denoising noisy NMR echo data. • Simulations and practical applications have verified the performance of improving quality of NMR echo data and enhancing the accuracy and reliability of inversion results with dictionary learning.

Characterization of Loratadine API and Simultaneous Quantification of Seven Potential Genotoxic Nitrosamine Impurities in Single Method by LC-MS/MS in Loratadine API and its Dosage Forms

Active pharmaceutical ingredients (APIs) of loratadine were characterized using spectroscopic methods such as infrared spectroscopy, mass spectroscopy, differential scanning calorimetry (DSC), 1H NMR, 2D nuclear magnetic resonance (2D-NMR) and 13C NMR. Nitrosamine impurities, which are considered under concern cohort according to the S2 FDA and ICH M7 guidelines, are highly genotoxic and their trace-level quantity must be controlled in drugs for safe human consumption. In this study, an ultra-sensitive, rapid and simple LC-MS/MS technique is developed to detect seven nitrosamine impurities (N-nitroso dimethylamine (NDMA), N-nitroso-N-methyl-4-aminobutyric acid (NMBA), N-nitroso diethylamine (NDEA), N-nitroso ethyl isopropylamine (NEIPA), N-nitroso diisopropylamino (NDIPA), N-nitroso methyl phenylamine (NMPA) and N-nitroso dibutylamine (NDBA) in loratadine drug) with potential genotoxicity. Chromatographic separation was attained by employing the Zorbax SB C18 of 150 × 3 mm and a column of 3.5 μ with 0.1% formic acid in water and methanol as mobile phases A and B, respectively. At the total run time of 20 min, the flow rate was 0.3 mL/min in the gradient mode of elution. Through multiple reaction monitoring (MRM), all the seven nitrosamine impurities were successfully ionized and then quantified in the positive mode of atmospheric pressure chemical ionization (APCI). The method was validated according to the ICH guidelines by estimating quantification and detection limits. For all the seven nitrosamine impurities, the method provided excellent S/N ratios with a high linearity range of 0.8-5.30 ppm for loratadine sample concentrations with a regression coefficient of >0.99. The recovery for the method was established with a protocol of three-step sample preparation and was satisfactory within 15-115%. The proposed method can be employed for the routine detection of nitrosamines in loratadine APIs and its doses.

Nuclear Magnetic Resonance (Nmr) Study on Micro Porosity Damage of Coal Body by Gas Desorption

Nuclear Magnetic Resonance (Nmr) Study on Micro Porosity Damage of Coal Body by Gas Desorption

Revealing the Toxicity-Enhancing Essence of Glycyrrhiza on Genkwa Flos Based on Ultra-high-performance Liquid Chromatography Coupled With Quadrupole-Orbitrap High-Resolution Mass Spectrometry and Self-Assembled Supramolecular Technology.

Researchers often focus on the mechanisms of synergistic agents, a few explore drug combinations that enhance toxicity, while few have studied the internal mechanism of compatibility enhancement in chemical level. Herein, we present a comprehensive analysis based on ultra-high-performance liquid chromatography coupled with quadrupole-Orbitrap high-resolution mass spectrometry (UHPLC-Q-Orbitrap HRMS) and a self-assembled supramolecular strategy, which reveals the toxicity-enhancing essence of glycyrrhizic acid originated in licorice when combined with Genkwa Flos. Through this method, we discovered the toxicity was enhanced through the formation of a supramolecular complex from Genkwa Flos/glycyrrhizic acid. The morphology and size distribution of the self-assembled nanoparticles were characterized by scanning electron microscopy and dynamic light scattering Furthermore, a total of 58 constituents (eight diterpenoids, 35 flavonoids, five phenylpropanoids, four nucleosides, two amino acids, and four other compounds) consisted from the supramolecular complex were identified through accurate-mass measurements in full-scan MS/data-dependent MS/MS mode. Based on the hydrophobic interaction of glycyrrhizic acid with yuanhuacine (one of main ingredients from Genkwa Flos), the supramolecular self-assembly mechanism was revealed with proton nuclear magnetic resonance (1H-NMR) and NOESY 2D NMR. The toxicity of Genkwa Flos and Genkwa Flos/glycyrrhizic acid supramolecular complex were compared through in vitro studies on L-02 cells using a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay; and 4′,6-diamidino-2-phenylindole (DAPI) staining was performed to further confirm the enhancement inhibition of Genkwa Flos/glycyrrhizic acid supramolecular complex than Genkwa Flos. This study provides fundamental scientific evidence of the formation of a self-assembled phytochemical supramolecular when Genkwa Flos and glycyrrhizic acid are combined, enabling to understand their clinical incompatibility and contraindication.

Dynamical properties of environmental high-performance composites with calcined clay

Concrete structures may be exposed to dynamic loadings within short periods such as earthquakes and vehicles load, resulting in substantial damage to human life and property because of the collapse of concrete structures. The research achievements on dynamic properties of high-performance composites with LC3 (HPC-LC3) are limited, although dynamic loadings are commonly encountered in infrastructure. The study aims to develop a new-green concrete product (HPC-LC3) with high dynamical properties and promote its mass use in a vibration service environment by investigating dynamical properties of HPC-LC3. Dynamical properties of structure can be promoted at material level by means of enhancing the inherent ability of cement-matrix materials to passively absorb the vibrational energy. Dynamic properties of traditional HPC may be improved by incorporated LC3 because of excellent mechanical properties. The fiber pull-out, thermogravimetric analysis (TGA), (nuclear magnetic resonance) NMR, and microstructure test were used to reveal the enhanced mechanism of dynamic properties in the HPC with LC3 (HPC-LC3), and the economic efficiency of HPC is also evaluated to promote its mass application. The results indicate that the dynamic properties of HPC-LC3 increased by 47% in damping capacity, 102% in storage modulus, 16% in energy dissipation, in comparison with the reference (HPC-OPC). Meanwhile, compared with the reference, the compressive and flexural strengths of LC3-50 increased by 14% and 27%. TGA and NMR results indicate that LC3-50 shows better hydration characteristics, longer alumina-silicate chain length (from 3.9 to 8) than HPC-OPC. The proposed composites reduced embodied energy, embedded CO2 emissions, and costs of HPC by up to 33%, 45%, and 7%, respectively. Thus, the green product (HPC-LC3) with 30%–40% calcined clay, high dynamic properties and more sustainable, will be recommended to mass use in a vibration service environment.

Synthesis, characterization and evaluation of stearyl acrylate-co-behenyl acrylate copolymer as a pour point depressant of waxy crude oil

Pour point depressant (PPD) has the competitive advantage of lowering the temperature of the wax appearance (WAT) and crude oil viscosity. In this paper, a novel PPD of poly stearyl acrylate-co-behenyl acrylate (SA-co-BA) in various mass ratios (1:1, 2:1, 3:1, 1:2 and 1:3) was effectively synthesized by solution radical polymerization method, and characterized by fourier transform infrared FTIR, proton nuclear magnetic resonance NMR, x-ray diffraction XRD and scanning electron microscopy SEM. The SA-co-BA PPD was evaluated on Malaysian crude oil via the pour point, the rheological and cold finger analysis to prevent the wax deposition at low temperature and improve flowability. The findings showed that the mass ratio (1:1) at 1000 ppm has a positive effect on the pour point depression from 11 to 2 °C. It was investigated from the rheological measurement that the viscosity of crude oil increases as the temperature decreases. Whereas, the viscosity decreases as the shear rate increases and as shear rate increases, shear stress increases. The flowability performance of the crude by the mass ratio of 1:1 at 1000 of the SA-co-BA concentrations have improved by 89.76%. The highest paraffin inhibition efficiency PIE of wax deposited was obtained at 1:1 of the mass ratio by 44.14%, indicating the smallest amount of wax is formed. This finding is interestingly attributed to the acrylate groups that have a long alkyl chain. Thus, SA-co-BA copolymer was demonstrated to be an appreciable pour point depressant that can prevent the wax deposition at low temperature and increasing the flowability of Malaysian crude oil.

Integrated Petrophysical Evaluation of Shale Gas Reservoirs for Wufeng-Longmaxi Formation in Southeast Chongqing

Shale gas is an important unconventional natural gas resource. Different from conventional oil and gas exploration, gas shale is not only the source rock of natural gas, but also the cap rock and reservoir. This paper presents a logging interpretation method for comprehensive evaluation of shale gas. Taking well A in southeast Chongqing from Sichuan Basin as an example, the shale gas reservoir of Wufeng-Longmaxi formation is evaluated. This method makes full use of conventional logging data (gamma ray, array lateral resistivity, density, neutron, acoustic, spectral gamma ray), unconventional log data (NMR Nuclear Magnetic Resonance, ECS Elemental Capture Spectroscopy) and core experiment data (X-ray Diffraction, Tight Rock Analysis, Methane Adsorption Isotherm). This method of combining logging data with core measurement can provide mineralogy, porosity, permeability, saturation, kerogen volume, total organic carbon content, absorbed gas content and free gas content. The methods provide a means to understand the petrophysical properties and reservoir quality of Wufeng-Longmaxi shale. This information can help to determine the “sweet spot” along the vertical to land and design a selective completion strategy to optimize well productivity.