Energy & Fuels最新文献

In the process of offshore oil and gas production and transportation, the formation of hydrates could lead to pipeline blockages and safety hazards. However, the specific role of crude oil saturates and the inhibition mechanism of industrial inhibitor Luvicap in hydrate formation remain to be systematically explored. In this study, the saturates of crude oil extracted from the Lingshui oilfield in the South China Sea and Luvicap were used as the subject. A self-designed platform with a high-pressure microfluidic chip and a microscopy visualization system was employed to investigate the kinetic impact mechanisms of the industrial inhibitor Luvicap on methane hydrate formation in the saturates system. The results showed that long-chain alkanes in the saturates promoted hydrate nucleation and growth, reducing the average induction time to 57.53 s (18.3% lower than that of the blank group) and increasing the growth rate to 157.74 μm/s (19.67% higher than that of the blank group). The inhibitory effect of Luvicap on the growth stage was significantly stronger than that on the hydrate nucleation stage, reducing the growth rate of the hydrates to 52.46 μm/s. Luvicap acts by adsorbing at the gas–liquid interface to block gas diffusion. The findings revealed that in the presence of saturates (a component of crude oil), Luvicap primarily inhibited the growth kinetics, providing experimental evidence for hydrate management based on component characteristics in oil and gas transportation systems.

Increasing atmospheric CO₂ levels call for secure, large-scale storage methods, and deep brine reservoirs represent the most widely available and scalable option. However, accurately predicting long-term CO₂ dissolution in these systems remains challenging and difficult because of the complex chemistry of temperature, heterogeneity, capillary forces, and geochemical reactions. This research employs advanced numerical simulations to evaluate these effects on the dissolution of CO₂ in heterogeneous, finite saline aquifers. A key novelty is the integration of experimentally derived diffusion coefficients, extended to higher temperatures via Arrhenius-based predictions, into the CMG simulator, thereby strengthening the linkage between laboratory data and reservoir-scale modeling. The simulations examine CO₂ dissolution across a wide temperature range (35–100 °C) while systematically evaluating the roles of capillary forces, aquifer heterogeneity, salinity, brine density evolution, and mineral–fluid reactions on plume morphology and trapping. To reduce computational complexity, three representative temperature levels (low, medium, and high ranges) were selected for the sensitivity analysis. Results reveal that at 35 °C, capillary forces enhance CO₂ dissolution efficiency by roughly 7%, driven by lower molecular kinetic energy and stronger interfacial interactions within confined pore spaces. Nonetheless, this effect diminishes at 100 °C due to the increased molecular energy and lower interfacial tension. Without geochemical interactions, dissolution efficiency increases by roughly 20% with temperature, from 45% at 35 °C to 70% at 100 °C. With geochemistry considered, redistribution of dissolved CO₂ into ionic and mineral-associated species reduces the apparent efficiency to around 36 and 47% at 35 and 100 °C, respectively. Finally, the findings demonstrate the necessity of accurate diffusion parametrization and the coupled consideration of temperature, capillary forces, geochemistry, and heterogeneity for predicting long-term CO₂ dissolution and trapping in deep saline aquifers.

In this study, we successfully prepared polyurethane microcapsules with regular morphology, uniform particle size and excellent monodispersity by means of microfluidic technology. The microcapsules use surfactant as the core material and polyurethane as the wall material, which significantly improves the controllability and repeatability of the traditional microcapsule preparation method. The prepared microcapsules not only have a minimum particle size of 44.5 μm, but also have a narrow particle size distribution (65–71 μm) and an average diameter of 67.4 μm, fully demonstrating excellent morphology control ability. In terms of performance evaluation, these microcapsules showed rapid targeted release characteristics in both light oil and heavy oil, especially in heavy oil, which could be completely dissolved within 10 s, indicating that they had good compatibility with oil molecules. Furthermore, the microcapsules encapsulated with AEO-3 surfactant can significantly reduce the oil–water interfacial tension from 27.68 mN·m^–1 to 6.67 mN·m^–1, which significantly enhances the peeling ability of oil droplets from the rock surface. In particular, when the concentration of microcapsules was 0.1 wt %, the Zeta potential of the dispersion system was −36.12 ± 0.7 mV, indicating that the system had high stability and effectively prevented the aggregation or precipitation of microcapsules. In addition, the microcapsules can maintain morphological integrity under high salt (10 wt % NaCl, 7 wt % CaCl₂) and high temperature (80 °C) conditions, showing excellent temperature and pressure resistance. Microscopic oil displacement experiments show that microcapsules can effectively enhance oil recovery by reducing oil–water interfacial tension and changing rock wettability, showing its great application potential in the field of enhanced oil recovery (EOR). These research results not only verify the advantages of microfluidic technology in the preparation of microcapsules, but also provide strong support for the development of intelligent oil displacement agents.

To further elucidate the modification effects of polyphosphoric acid (PPA) on different oil-source base asphalts from the perspective of the mechanical properties of asphalt colloidal components, an improved separation device was designed to isolate colloidal components from PPA-modified and unmodified asphalts derived from different oil-source regions. The rheological properties of the maltene components were evaluated across a broad temperature range using a dynamic shear rheometer. The nanomechanical properties of solid-state asphaltenes were examined using atomic force microscopy. The variations in polarity and solubility of resins and aromatics induced by PPA were quantified by thin-layer chromatography with flame-ionization detection (TLC-FID). The results indicated that PPA significantly increased the complex modulus of resins by 2.5 to 3 times. The enhancement effect of 115-grade PPA generally exceeded that of 105-grade PPA. TLC-FID confirmed that PPA simultaneously polymerized rigid aromatic fragments and cyclized alkyl segments in the aromatic and resin fractions. By polymerizing active sites in asphaltenes, PPA introduced a small amount of ultrahard substance into the Derjaguin–Muller–Toporov (DMT) modulus image of the asphaltenes, a phenomenon more pronounced with long-chain PPA. This resulted in increases of 7.4% to 25.6% in the maximum DMT modulus and 10 to 30 MPa in the average DMT modulus of the asphaltenes. This study innovatively investigated the effects of PPA on different oil-source asphalts from the perspective of the mechanical properties of the four components, revealing the material transformation mechanisms within asphalts under the influence of PPA and the reasons for the differences in modification effects among asphalts with different molecular structures. Moreover, the research methodology provides a reference for studies of other chemically modified asphalts.

Solvothermal liquefaction (STL) is a promising thermochemical technique for recycling organic waste materials. In this study, three polymer feedstocks, high molecular weight polystyrene (PS), styrene–butadiene rubber (SBR), and scrap tire waste (STW), were subjected to STL under subcritical (270 °C) and supercritical (320 °C) conditions, using toluene as the solvent. The resulting liquid products were characterized by atmospheric pressure photoionization Fourier transform ion cyclotron resonance mass spectrometry (APPI FT-ICR MS), carbon-13 nuclear magnetic resonance (¹³C NMR), and Fourier transform infrared (FT-IR) spectroscopy. All feedstocks yielded significant amounts of liquid products. PS was fully liquefied at both temperatures, whereas SBR and STW left 16–22 wt % solid residues. Spectroscopic analyses showed that PS primarily decomposed into styrene monomers and small oligomers. In contrast, SBR and STW produced complex mixtures of aliphatic and polycyclic aromatic hydrocarbons (PAHs) and their derivatives. The SBR-derived liquids were rich in large, alkylated PAHs, while STW mainly generated polyisoprene oligomers with sulfur and oxygen functionalities. Supercritical conditions resulted in higher liquid yields than the subcritical ones but also increased the aromaticity of the products. Based on the results, STL is a promising thermochemical technique for waste polymer valorization but requires fine-tuning and further product downstream fractionation and processing.

The main active components in kinetic hydrate inhibitor (KHI) formulations are one or more key polymers. Designing the polymers to be effective requires consideration of two main topics: first, some basic structural features of the polymer need to be optimized, and second, how the polymer structure behaves in the aqueous environment under laboratory and field conditions. A review series structured into three independent parts systematically summarizes the key factors affecting KHI performance. This paper serves as the stand-alone first part of the review series, which sums up the structural features that must necessarily be considered in designing an effective KHI polymer. This review comprehensively discusses the critical structural features of KHI polymers, mainly including the amphiphilic functional groups in the repeating units, optimal polymer chain length, stereochemical configuration, functional end-capping groups, linear/branched chain structures, and monomer sequencing in copolymers. The potential inhibition mechanisms associated with the key molecular structural factors governing KHI efficacy are further clarified. The synergistic effect exhibited by these structural features enables KHI polymers to exert dual functional roles: first, perturbing the molecular behavior of the water phase, and second, adsorbing onto the surface of hydrate crystals. These combined actions collectively contribute to the kinetic inhibition of hydrate nucleation and subsequent crystal growth. This review synthesizes current understanding into a coherent framework to enable the rational design of high-performance KHIs.

In the process of offshore oil and gas production and transportation, the formation of hydrates could lead to pipeline blockages and safety hazards. However, the specific role of crude oil saturates and the inhibition mechanism of industrial inhibitor Luvicap in hydrate formation remain to be systematically explored. In this study, the saturates of crude oil extracted from the Lingshui oilfield in the South China Sea and Luvicap were used as the subject. A self-designed platform with a high-pressure microfluidic chip and a microscopy visualization system was employed to investigate the kinetic impact mechanisms of the industrial inhibitor Luvicap on methane hydrate formation in the saturates system. The results showed that long-chain alkanes in the saturates promoted hydrate nucleation and growth, reducing the average induction time to 57.53 s (18.3% lower than that of the blank group) and increasing the growth rate to 157.74 μm/s (19.67% higher than that of the blank group). The inhibitory effect of Luvicap on the growth stage was significantly stronger than that on the hydrate nucleation stage, reducing the growth rate of the hydrates to 52.46 μm/s. Luvicap acts by adsorbing at the gas–liquid interface to block gas diffusion. The findings revealed that in the presence of saturates (a component of crude oil), Luvicap primarily inhibited the growth kinetics, providing experimental evidence for hydrate management based on component characteristics in oil and gas transportation systems.

Hydraulic fracturing has considerable potential for stimulating natural gas hydrate reservoirs (NGHRs). However, hydrate dissociation-induced mechanical weakening of sediments, together with gas–water two-phase flow-driven fine particle migration, poses significant engineering challenges, including proppant embedment and fracture plugging, which severely degrade fracture conductivity. This study employed a visual sapphire reactor to investigate the effects of proppant-filled layers on hydrate formation and dissociation behavior. X-ray computed tomography (X-ray CT) was further utilized to characterize fine particle migration patterns and pore-structure damage within the proppant-filled layer. The results indicate that conductivity impairment predominantly occurs during the constant-pressure stage and the subsequent gas output stage. Increasing proppant concentration and reducing proppant particle size significantly mitigate conductivity damage while enhancing gas production rates. Moreover, a gradient-filling strategy using 20–40 and 40–60 mesh proppants effectively optimized fracture conductivity, yielding total porosity increases of 84.6% and 23.9%, respectively, relative to uniform proppant filling. Additionally, pore-structure damage was found to vary nonlinearly with decomposition pressure, highlighting a coupled relationship between damage severity and gas–water two-phase flow velocity, which in turn influences particle migration intensity and spatial distribution. These findings provide valuable guidance for optimizing proppant gradation and developing effective protective strategies, and offer a useful reference framework for integrating hydraulic fracturing and sand control to support sustainable and stable gas production from hydrate reservoirs.

Petroleum is a complex matrix, with its physical and thermodynamic properties, as well as mixture behavior, primarily dependent on its constituents and their relative quantities. Adequate characterization of crude oil constituents is indispensable for determining its thermodynamic behavior and is of great importance for all stages of its value chain from reserve estimation to projects for production, lifting, transportation, refining, and distribution of its derivatives. Consequently, there is significant interest in conducting in-depth studies of its composition. High-resolution mass spectrometers have been employed universally to analyze petroleum, giving rise to the field of petroleomics. High-field techniques such as Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) and Orbitrap MS are fundamental in petroleomics studies. Nevertheless, the high resolution of these instruments introduces certain sample variations and spectral alignment challenges. To address these limitations, data processing methodologies have been developed to align, concatenate, and correct baseline distortions in the spectra of complex matrices. This article aimed to conduct a systematic investigation of the development of chemometrics (multivariate analysis, machine learning, or artificial intelligence) in petroleomics applied to high-resolution instruments such as FT-ICR MS and Orbitrap MS.

Solvothermal liquefaction (STL) is a promising thermochemical technique for recycling organic waste materials. In this study, three polymer feedstocks, high molecular weight polystyrene (PS), styrene–butadiene rubber (SBR), and scrap tire waste (STW), were subjected to STL under subcritical (270 °C) and supercritical (320 °C) conditions, using toluene as the solvent. The resulting liquid products were characterized by atmospheric pressure photoionization Fourier transform ion cyclotron resonance mass spectrometry (APPI FT-ICR MS), carbon-13 nuclear magnetic resonance (¹³C NMR), and Fourier transform infrared (FT-IR) spectroscopy. All feedstocks yielded significant amounts of liquid products. PS was fully liquefied at both temperatures, whereas SBR and STW left 16–22 wt % solid residues. Spectroscopic analyses showed that PS primarily decomposed into styrene monomers and small oligomers. In contrast, SBR and STW produced complex mixtures of aliphatic and polycyclic aromatic hydrocarbons (PAHs) and their derivatives. The SBR-derived liquids were rich in large, alkylated PAHs, while STW mainly generated polyisoprene oligomers with sulfur and oxygen functionalities. Supercritical conditions resulted in higher liquid yields than the subcritical ones but also increased the aromaticity of the products. Based on the results, STL is a promising thermochemical technique for waste polymer valorization but requires fine-tuning and further product downstream fractionation and processing.