Chemistry and Technology of Fuels and Oils最新文献

In order to understand the problem of sediment sources in the Xujiahe Formation of the Central Sichuan Uplift, high-density two-dimensional seismic data was used, and LCS2 (the second section of the Xujiahe Formation) was taken as the research object. Combined with logging interpretation results, typical seismic facies were identified within the sequence, including clinoform seismic facies, progradational reflection seismic facies, and incised valley seismic facies. The progradational reflection seismic facies can be divided into two types: S-shaped and oblique progradational reflection facies. The oblique progradational reflection seismic facies representing the rapid filling environment of sediments are mainly distributed in the southeast of the study area, while the northwest mainly develops relatively low-energy sedimentary mechanisms of S-shaped seismic facies. The incised valley seismic facies are mainly distributed in the eastern and southeastern parts of the work area. On the plane, the incised valley seismic facies have a trend of gradually widening and shallowing towards the northwest direction. In addition, the distribution of sedimentary facies was analyzed using seismic attributes. The southeastern and central parts of the study area are mainly composed of proximal sand-rich braided river alluvial plains, while the northwestern part is mainly composed of distal mud-rich braided river alluvial plains. The distribution of sedimentary facies generally shows a southwest to northeast distribution. From southeast to northwest, the sedimentary facies show a clear trend of changing from sand-rich to mud-rich. Based on the comprehensive distribution characteristics of seismic and sedimentary facies, it is believed that the river in the Central Sichuan Uplift basically enter the region from the south or southeast, and transport sediments from southeast to northwest. Based on the above evidence, it is inferred that the sedimentary material of the Xujiahe Formation in the Central Sichuan Uplift mainly comes from the «Qianzhong Ancient Uplift» or «Fanjing Mountain Ancient Land» on the southern and southeastern of the Sichuan Basin.

Geological carbon storage is considered to be an effective measure to mitigate climate crisis. The method in which CO₂ is stored depends on its phase state and the depth at which it is injected. In this study, the fault-reservoir system is constructed to elucidate the fault leakage behaviors and CO₂ migration in different geological storage environments. Whether CO₂ is buoyant or sinking depends on the fluid density difference between CO₂ and H₂O. When carbon dioxide is injected into deep saline aquifer, CO₂ would preferentially migrate upward along the fault plane due to CO₂ buoyancy forces, and CO₂ plume accumulates beneath the caprock and floats at the top of the reservoir eventually. For CO₂ storage in deep ocean reservoir and volcanic basalt, no upward migration of CO₂ plume is observed during carbon storage. Fault plane is the preferential pathway for carbon downward transportation during ocean-based CO₂ storage, providing a virtually unlimited environment. Compared with deep ocean storage, the much shorter sinking times makes volcanic basalt for carbon storage safer and more effective. It is illustrated that the fluid density difference between CO₂ and H₂O is the decisive factor in determining CO₂ sinking velocity. This investigation of searching CO₂ sinking reservoirs provides a promising alterative reference for remove and storage large volumes of the greenhouse gas.

Calcareous interbeds control the migration of oil and water in marine strata. However, in China, the origins of such calcareous interbeds have not been investigated in detail. In this paper, we present a study of calcareous interbeds in marine strata of the Zhujiang Formation in the Wenchang Oil Field, which is located in the southeast of Hainan Province, China. The lithological characteristics, types and features of diagenesis, and formation of the calcareous interbeds were investigated using core, thin-section, scanning electron microscopy, and cathodoluminescence observations, and stable carbon and oxygen isotope data. The calcareous interbeds consist of mixed sediments, which are dominated by bioclastic limestones containing terrigenous clasts, along with subordinate calcareous sandstone. The interbeds are densely cemented. The bioclasts are dominantly brachiopods, pleopods, and foraminifera, with minor amounts of echinodermata, bivalves, red algae, ostracods, and bryozoa. Diagenesis involved calcitic cementation, associated with relatively weak compaction. Carbon and oxygen isotopic data indicate the pore water that formed the carbonate cement was mostly sourced from seawater and minor amounts of meteoric water. The degree of carbonate cementation was significantly related to the bioclast content. On the basis of our study, a genetic model for the macroscopic and microscopic formation of calcareous interbeds is proposed.

It is common knowledge that in-situ combustion is highly promising method for improving heavy oil recovery. The present research explores the effects of Cobalt-ligated catalysts derived from sunflower oil (CoSFO) and tall oil (CoTO) on heavy oil oxidation, aiming to enhance in-situ combustion process. Through differential scanning calorimetry (DSC) we assessed the oxidation kinetics of heavy oil in the presence and absence of these catalysts. Our findings indicate that both CoSFO and CoTO significantly improve the oxidation process, particularly in the high-temperature oxidation (HTO) phase crucial for combustion front stabilization. Notably, CoTO demonstrated superior efficacy in reducing oxidation times across all conversion levels, suggesting its potential to optimize the efficiency of EOR techniques. This research highlights the promise of Cobalt-ligated catalysts in advancing heavy oil recovery and suggests directions for future studies to further investigate their industrial applications.

The article reviews the most common analytical methods for calculating the parameters of minimum reflux condition during fractionation of multicomponent mixtures, taking account of the specified separation products quality requirements. A calculation procedure that makes it possible to simplify determination of minimum reflux or vapor ratios as well as of distillate or residue compositions under minimum reflux condition compared to the known methods is proposed and described.

Shale gas is an extremely important unconventional oil and gas resource, and its efficient development can effectively alleviate the current tense energy situation. However, shale gas reservoirs often have extremely poor permeability, and reservoir transformation has become a key technology for achieving their efficient development. However, the commonly used hydraulic fracturing technology is difficult to achieve its target production capacity, and other engineering technologies related to reservoir transformation urgently need to be proposed and attempted. The synergistic operation of oxidation dissolution and acid fracturing may provide new ideas for the effective transformation of shale reservoirs. To this end, a comparative analysis was conducted on the synergistic effects of oxidation dissolution and acid fracturing operations in improving shale gas production capacity. The research results indicate that the dissolution effect of oxidants is more effective than acid solution in the transformation process of shale reservoirs. The use of acid only widens the crack width from the initial 4.4 mm to the final 5.1 mm. However, the use of oxidants will result in the final width of hydraulic fractures reaching 8.3 mm. Meanwhile, the effects of acid concentration and oxidant concentration on hydraulic fracture conductivity and shale gas production capacity were investigated. The results indicate that increasing the acid concentration below the low concentration range can significantly enhance the fracture conductivity, thereby promoting the production capacity of shale gas. However, within a higher concentration range, its effect on shale gas production is significantly limited. It is recommended to set the acid concentration design value at 0.5 wt% during the acidizing and fracturing reservoir transformation process of the shale gas reservoir in Changning block. In addition, an increase in the concentration of oxidants can widen the width of fractures and increase permeability, thereby promoting the migration and extraction of shale gas. To avoid the increase in development costs caused by high oxidant concentration in the working fluid, it is recommended to design the oxidant concentration at 3 wt%.

As a non-invasive tool, ultrasound waves can be applied to probe gaseous content of the drilling fluid in offshore oil-drilling operations. The approach is believed to improve sensitivity and accuracy of a gas-kick detection system. In this research, four types of bubble flow are designed to simulate undeveloped gas kicks, and their effects on changes of ultrasound waves are investigated. The bubbles are found to have changed power distribution of the sound waves that have been reflected by the bubbles and received by side sensors. The pattern of power spectrum changes around the master frequency is found to be closely related to the type of bubble flow. Such changes are grouped on the basis of cluster analysis, and it is found that bubble strings and bubble groups would produce substantially different effects and that bubble mergences would largely alter spectral property of the sound waves. By establishing relationship between power-change pattern of sound waves and the behavior of a bubble flow, the research is intended to seek a more predictive way of recognizing early-stage gas kicks for offshore oil-drilling practices.

This study investigates the catalytic effects of Nickel-ligated catalysts derived from tall oil (NiTO) and sunflower oil (NiSFO) on the oxidation of heavy oil. Thermogravimetric (TG) analysis were employed to assess the thermal behavior and kinetics of heavy oil degradation. The Friedman isoconversional method provided the activation energies (Ea ), which were then used to derive thermodynamic parameters including changes in enthalpy (ΔH), entropy (ΔS), and Gibbs free energy (ΔG). The TG analysis revealed that both NiTO and NiSFO influence the degradation kinetics of heavy oil. Moreover, NiTO exhibited a consistent catalytic effect across a wide range of conversions, lowering the onset temperature of degradation and promoting faster degradation rates, which suggests a rapid breakdown at lower temperatures. Conversely, NiSFO demonstrated a substantial decrease in activation energy at mid-range conversions, indicating a highly efficient catalysis during these stages. In addition, thermodynamic analysis indicated that both catalysts alter the energetic profile of the reaction. Notably, NiSFO reduced ΔG significantly at lower conversions, enhancing the spontaneity of the reaction, while NiTO was associated with lower ΔG values across most conversions, implying a more favorable reaction throughout the process. The findings suggest that the choice of catalyst can be tailored based on the desired conversion range and reaction spontaneity in industrial heavy oil processing. These insights could be crucial for optimizing thermal treatments in heavy oil upgrading, offering potential improvements in the efficiency of in-situ combustion and enhanced oil recovery technologies.

Utilizing emulsion polymerization, a microcapsule breaker with a polystyrene-polyacrylamide core-shell structure was synthesized. Ammonium persulfate served as the breaker, polystyrene as the shell, and polyacrylamide as the drug-carrying agent. The results demonstrated that the synthesized microencapsulated gel-breaker exhibited a uniform spherical shape, superior water dispersion, and enhanced thermal stability. Conductivity tests indicated that the core-shell structure of the microcapsules effectively regulated the release of ammonium persulfate as a gel-breaking agent, resulting in delayed polymer gel-breaking.