Understanding the polydisperse behavior of asphaltenes during precipitation

h i g h l i g h t s The PC-SAFT equation-of-state is used to study asphaltene phase behavior. The effect of asphaltene polydispersity on asphaltene phase behavior is studied. Results of monodisperse and polydisperse asphaltenes modeling are compared. A wide range of crude oils are considered for the study. An explanation for the observed behavior is provided based on Flory-Huggins theory. a r t i c l e i n f o b s t r a c t Asphaltenes are a polydisperse fraction of the crude oil, the phase behavior of which is significantly affected by the changes in pressure, temperature and composition. The focus of this study is to model the polydisperse asphaltenes' precipitation onset condition and the amount of precipitate from solvent-diluted crude oils using the Perturbed Chain form of the Statistical Associating Fluid Theory (PC-SAFT) over a wide range of crude oil density. Heavy oil and bitumen production can involve diluting with paraffinic solvents. Different fractions of the polydisperse asphaltenes thus precipitated are predicted and when compared to the experimental data show a remarkable matching for different solvents. A comparison of monodisperse and polydisperse modeling is also performed. This work illustrates the successful application of PC-SAFT for predicting the phase behavior of polydisperse asphaltenes and in particular from heavy oil and bitumen

Synthesis of Cobalt nanocomposite hydrogel based on Acrylamide as an efficient chemical for sand control in the oil reservoir

Hypothesis: Sand production from oil reservoirs is marked by many problems, such as well productivity reduction, operating equipment corrosion, and an increase in production costs; therefore, sand control in unconsolidated reservoirs is crucial for operating companies. Chemical injection into the production vessel, in order to strengthen and reduce sand formation, would be one of the most important methods of sand control.Methods: In this study the effectiveness of a Co[AM-AMPS-AAC]/PEI-MBA(CO) hydrogel nanocomposite in sand control was investigated. The acrylamide-based nanocomposite is strengthened structurally and thermally by the addition of double crosslinkers and nanoparticles. Structural, morphological, thermal, rheological, compressive strength and flooding tests were carried out to define and assess its efficacy.Findings: According to X-ray diffraction test findings, nanoparticles are evenly distributed throughout the structure. Morphological tests demonstrated the production of a dense, homogenous, and porous structure and validated the presence of nanoparticles in the structure. According to the thermal gravimetric test, adding nanoparticles increased the starting temperature of degradation from 80 to 195°C. The strain and frequency sweep rheological tests investigated the behavior of the material under different strains and stresses; they confirmed the preservation of the strong structure and linear viscoelastic behavior at a temperature of 90°C, strains between 0.1 and 20%, and frequencies between 0.1 and 10 Hz. The injection of 0.5 PV (pore volume) of 1% (by wt) nanocomposite to the sand pack resulted in a 730% increase in the axial strength of the sand pack according to the compressive strength test and 90% reduction in sand production measured by the chemical flooding test. Considering the stability and proper efficiency in the reservoir's harsh conditions, having linear viscoelastic properties, increasing compressive strength, and reducing sand production, the hydrogel nanocomposite designed in this research is proposed as a new and optimal product to control sand production and migration

Design and fabrication of a Preformed Thixotropic-Viscoelastic Nanocomposite hydrogel system (PNCH) for controlling sand production in reservoirs

In this study, the performance of preformed dual crosslinked nanocomposite hydrogels (PNCH) consisting of acrylamide, 2-acrylamide-2-methylpropane sulfonic acid, maleic acid, and acrylic acid in sand control was investigated. Also, the effects of three nanoparticles (NPs) of iron (PNCH1), silicon (PNCH2), and bentonite (PNCH3) on the PNCH structure were studied. The morphology, equilibrium swelling ratio (ESR), rheology, thermal strength, zeta potential, and compressive strength were experimentally analyzed. According to the XRD results, the NPs were completely dispersed in all three samples. The results of SEM and EDS tests confirmed the presence of NPs within the PNCHs with a dense, homogeneous, and porous structure. The results of the ESR at distilled and formation water at ambient temperature for PNCHs (1), (2), and (3) were (13.9,4.55), (15.45, 6.35), and (12.9, 4.8), also at reservoir temperatures ESR results were reported (78, 17.5), (89, 13), and (70,12.9) respectively. From the TGA results, structure destruction of PNCHs starts at 222, 225, and 202 °C respectively so the addition of 1 wt% of NPs increased the structure destruction from nearly 80 °C to more than 200 °C. Based on the results of the strain sweep test, structures of PNCHs can cause viscoelastic behavior with the maximum elastic modulus of 29,000, 8430, and 10,800, and critical strain of (10%, 19.3%, and 10.8%) respectively. The loop test results confirmed the time-dependent viscoelastic properties of thixotropic in all structures. Finally, in compressive strength test revealed that adding 0.5 pore volume of 1 wt% of PNCH into the sandpack increased its strength by 980%

The Influence of Polymer Type and Concentration on the Metoprolol Mass Transfer in Extended-Release Tablet of Metoprolol Succinate

Introduction: One of the main objectives of reservoir engineering studies is to increase the production of hydrocarbon reservoirs with an optimal method. One of the artificial lift methods in wells is the gas lift. This system increases the oil production flow rate by reducing the pressure at the bottom of the well and increasing the pressure at the wellhead. In this method, by injection of high-pressure gas into the well’s column, the average density of the well fluid is reduced, and through this, the well is reactivated. Method: In the current study, the simulation of a gas lift system in the horizontal and inclined wells was investigated. The pressure changes at the end of a simulated pipeline with the ability to change the angle from horizontal to inclined when the continuous fluid is water and the injected fluid in the air is investigated. Findings: The results obtained from the current study have been investigated by the PIPESIM Software and the GLR parameter sensitivity analysis. The main objective of the current study is to find the optimal flow rate of the injected gas, which is specified after analysis of the figures obtained from the experiment. Discussion and Conclusion: One of the advantages of conducting this empirical research compared to simulation with PIPESIM Software is that pressure drop fluctuations can be seen along the pipeline in empirical operations, which is not possible in this software

Investigation of Six Imidazolium-Based Ionic Liquids as Thermo-Kinetic Inhibitors for Methane Hydrate by Molecular Dynamics Simulation

International audienceThe thermo-kinetic inhibition mechanism of six imidazolium-based ionic liquids (ILs) on methane clathrate hydrate formation and growth is studied in this work using classical molecular dynamics (MD) simulation. The ionic liquids investigated include 1-(2,3-dihydroxypropyl)-3-methylimidazoliumbis(fluorosulfonyl)imide ([C3(OH)2mim][f2N]), 1-(2-hydroxyethyl)-3-methylimidazolium bis(fluorosulfonyl)imide ([C2OHmim][f2N]), 1-ethyl-3-methylimidazolium tetrafluoroborate ([C2mim][BF4]), 1-butyl-3-methylimidazolium tetrafluoroborate ([C4mim][BF4]), 1-butyl-3-methylimidazolium acetate ([C4mim][OAc]) and 1-ethyl-3-methylimidazolium ethylsulfate ([C2mim][EtSO4]). Simulations showed that [C2OHmim][f2N] and [C3(OH)2mim][f2N] are strongly hydrated compared to other ILs because of hydrogen bonding between OH groups of the cation and water molecules. They also exhibit high diffusion rates towards crystal surface and bond to it through strong intermolecular interactions. As a result, these two ILs are stronger thermo-kinetic inhibitors for formation and growth of methane hydrates compared to other ILs studied in this work as well as conventional inhibitors like methanol and NaCl. The simulations also revealed that cations of [C3(OH)2mim][f2N] and [C2OHmim][f2N] show that the presence of ions near the hydrate crystal causes hindrance for water and guest molecules adsorbing on the hydrate surface, which inhibits the growth of hydrate crystals. In addition, it is shown that [C3(OH)2mim][f2N] and [C2OHmim][f2N] are more likely to inhibit hydrate formation. Research Highlights:  Investigation of kinetic inhibition mechanism of six imidazolium-based ILs on methane hydrates formation and growth using MD simulations.  Investigation of thermodynamic inhibition mechanism of six imidazolium-based ILs on methane hydrates growth by MD simulations.  Drawing a comparison between methane hydrate inhibition Effectiveness of ILs

Effects of Paraffinic Group on Interfacial Tension Behavior of CO₂–Asphaltenic Crude Oil Systems

The interfacial tension (IFT) of a crude oil/CO₂ system is recognized as the main property affecting the efficiency of CO₂ flooding during an enhanced oil recovery (EOR) process. The addition of a paraffin group hydrocarbon to asphaltenic crude oils as an asphaltene precipitant component is aimed to mimic the asphaltene precipitation process during crude oil production and transportation. Asphaltene precipitation would critically affect the interfacial behavior of crude oil/CO₂ systems. In the first part of this study, the equilibrium densities of oil samples which contain <i>n</i>-heptane at different ratios were measured over varying pressures at 323 K. Then, the equilibrium IFT between CO₂ and the crude oil samples was measured using the axisymmetric drop shape analysis (ADSA) technique. This investigation was followed by measuring the minimum miscibility pressure (MMP) of the oil/CO₂ systems using the vanishing interfacial tension (VIT) technique. The results showed that the density of oil sample increases linearly with pressure. Moreover at a constant pressure and temperature, the density was linearly decreased with <i>n</i>-heptane content of the crude oil sample. Linear correlations between density, <i>n</i>-heptane content, and pressure at the temperature of 323 K for each oil sample were also noticed. The results of IFT tests indicated that asphaltenic crude oil samples have two slope IFT-pressure behavior. It was found that for oil samples with high asphaltene content (9 wt %), the higher the <i>n</i>-heptane content of the oil sample is, the lower is the pressure of the IFT’s slope change, while for low asphaltenic oil sample (0.56 wt %) an increase of <i>n</i>-heptane has little effect on the point of the slope change of the IFT. Consequently, it was found that asphaltenes increase the rate and magnitude of the light component extraction in oil/CO₂ systems. The experimental results showed that the MMP of the oil samples decreased linearly with the <i>n</i>-heptane content of the oil sample. The linear relation between the MMP and <i>n</i>-heptane content revealed the crucial role of the paraffinic group as the controlling miscibility component of the crude oils

Applications of the quartz crystal microbalance in energy and environmental sciences: From flow assurance to nanotechnology

In the last decade, there has been a swift development in several scientific research works in which the quartz crystal microbalance (QCM) technique has played a critical role in unravelling different aspects of energy and environmental materials and biological substances as well as all corresponding molecular interactions within those media. We comprehensively review the numerous types of surface chemistries, including but not limited to hydrogen bonding, hydrophobic and electrostatic interactions, self-assembled monolayers and ionic bonding, that are monitored using QCMs in a variety of fields such as energy and chemical industries in addition to the biology, medicine and nanotechnology disciplines. Furthermore, we critically review the QCM's diverse applications, which include the detection of organic and inorganic scale formation and deposition onto solid surfaces and evaluation of respective inhibitors, monitoring of adsorption/desorption of hydrocarbon surface-active species onto/from solid rock surface, detection of virions on the surface, diagnostics of various diseases, detection of protein aggregation, and detection of medicines. Focusing on the recent growth of applications of QCMs in each field within the last few years, some of the barriers, limitations, and prospective uses are succinctly highlighted. We hope that this review can pave the way for other researchers worldwide to expand their surface chemistry studies in the abovementioned fields using QCM based technologies