High-viscosity Oil Research Articles

Hydrostatic And Hydrodynamic Bearing On Grinding Machine

In recent years, the demand for hydrostatic bearing application has been increasing due to the possibilities and advantages they offer. Advances in the understanding of hydrostatic lubrication and the improvement of computer technology have opened new avenues for improving hydrostatic bearing performance and precision. This paper reviews the geometry, advantages and disadvantages of hydrostatic bearings, including the hydraulic system. Hydrostatic bearing applications operate using relatively high viscosity oil, but have the potential for extremely low motion errors with high damping, high stiffness and high load capacity. Another important advantage of hydrostatic bearing is the negligible wear of the sliding surfaces, which are completely separated by the oil film. In general, pocket depths of 0.5-5 mm and bearing clearance of 0.001-0.01 mm are preferred in hydrostatic bearings. In hydrodynamically lubricated bearings, the friction efficiency between the spindle and the bearing can be controlled when the spindle shaft starts the rotational movement of the spindle shaft while the spindle shaft passes from the stationary state to the contact state and when the appropriate speed is reached. Therefore, the liquid film thickness in hydrodynamic bearings is at the level of 0.0254 mm. In order for these systems to operate safely and efficiently, the presence of a suitable lubricant is always required. Hydrostatic grinding and hydrodynamic grinding machines were used in the experiments carried out within the scope of this study, and especially the crusher roll with dimensions of 250*1000 mm was used in the experiments. Depending on the use of the grinding machine, the advantages of hydrodynamic bearing and hydrostatic bearing options were compared. In this comparison data, especially the results of how much current these two different bearing applications draw during the operation of the grinding machine and what level of surface roughness they produce are analyzed.

Application of aluminum nanoparticles in reagents for oil viscosity reduction

The problem of extracting hard-to-recover reserves, which belong to the category of heavy and highly bound oil, is one of the most pressing oil industries. Many mining companies actively use physical and chemical methods to solve this problem. The use of nanotechnology in physical and chemical methods for increasing oil production is a relatively new area. Nanoparticles easily enter the regime, their size allows them to spread more easily in porous media without reducing permeability. The main goal of the research was to reduce oil viscosity and achieve increased production. In order to increase oil recovery, the proposed method for reducing oil viscosity in reservoir conditions based on treating the bottomhole zone of production wells with a solution of caustic soda and nanoparticles affects the dimension of 40-60 nm (concentrations of 1, 0.1 and 0.01 %). The nanoparticles were obtained using an electrical conductor method and studied by transmission electron microscopy. Determination of surface tension using a DSA30 device (Kruss, Germany) using the pendant drop (PD) method. The samples for testing were oil samples, visible wells No. 222761 Binagadi-North, No. 220051 Fatmai area and No. 221937 Kirmaki area, trading company "Binagadi Oil". Based on experimental data, it was found that the proposed composition reduces the viscosity of oil by several times in all three experimental samples, nanoparticles have a positive effect on reducing viscosity, the greatest effect was noted with 0.01% nanoparticles, this composition can be used to increase the production of high-viscosity oils. Keywords: nanotechnology; metal nanoparticles; enhanced oil recovery; reduce oil viscosity.

Methodology for optimizing high-viscosity oil production using a nature-inspired algorithm

To maintain reservoir pressure above the saturation pressure of oil with gas and effectively displace oil from the reservoir, flooding remains an established operating practice in the fields of the Russian Federation. In recent years, theoretical and practical research into this method of operation has been actively developing. Thus, the low efficiency of oil displacement by flooding has been established in conditions of low oil mobility compared to water, which is especially evident in heterogeneous reservoirs. The highest reduction in the efficiency of the process of replacing oil with water is observed during the development of highly viscous oil fields. For these difficult conditions, polymer flooding technology is especially promising, because the polymer, thickening the water, increases its viscosity, increasing the displacing ability of water. However, for the practical application of polymer flooding, it is necessary to optimize the process by justifying technological parameters (polymer concentration, injection rate) to achieve maximum efficiency. For this purpose, the paper presents a methodological approach based on the use of a nature-inspired optimization algorithm ‒ a flock of migratory birds, used to solve a number of practical nonlinear optimization problems. Keywords: flooding; polymer compositions; mathematical modeling; optimization objective function; nature-inspired algorithms; migrating bird algorithm; net present value.

ЭФФЕКТИВНОСТЬ ПРИМЕНЕНИЯ ФИЗИЧЕСКОГО ВОЗДЕЙСТВИЯ НА ПРОДУКТИВНЫЙ ПЛАСТ ДЛЯ УВЕЛИЧЕНИЯ НЕФТЕОТДАЧИ ПЛАСТОВ

This article assessed the technical and economic efficiency of using physical impact on the productive formation in one of the fields in Western Kazakhstan. World experience in using this technology in fields testifies to its high technological efficiency. To optimize oil production, changes in oil viscosity, increase in oil production, and decrease in water content were analyzed. All Cretaceous horizons are characterized by good reservoir properties. However, the high viscosity of oil and insufficient cementation of the rocks forming the horizons limit the complete extraction of the product. The determination of phase permeabilities in the oil-water system was carried out in laboratory conditions during stationary filtration. As a result of the use of physical impact, the viscosity of oil decreased by almost half, from 700 cP to 480 cP, which helps to increase oil production and reduce the water content in the produced products.

Influence of Surface Wettability of Nonhomogeneous Proppant on Hydraulic Fracture Inflow Performance.

Quartz sand proppant is widely used in hydraulic fracturing and the extraction of low-permeability reservoirs to prevent fracture closure and enhance reservoir recovery effectively. The influence of proppant size and type on well productivity has been widely studied, but the mechanism of proppant surface wettability on the hydraulic fracture inflow performance has not been thoroughly investigated. To further understand the influence of proppant wettability on fracture inflow performance, in this work, a hydrophobic quartz sand proppant was prepared by a simple dip-coating method using silane solution with a static water contact angle of 136.8° in air, and three types of filtration layer models were prepared according to the mass ratio of hydrophilic/hydrophobic particles, hydrophilic (4:0), hybrid (2:2), and hydrophobic (0:4), to analyze the effects of quartz sand proppant wettability on the oil/water distribution and conductivity performance in the three filter layers. The preliminary results show that (1) under different mesh sizes of quartz sand, different emulsion concentrations, and high-viscosity oil samples, the hydraulic performance of the hydrophobic quartz sand filter layer is generally better than that of the hydrophilic quartz sand filter layer; and (2) the hydraulic performance of the hydrophobic quartz sand filter layer decreases as the concentration of the emulsion increases, the hybrid quartz sand filter layer is basically unaffected and its hydraulic performance is relatively stable, and the hydraulic performance of the hydrophilic quartz sand filter layer is more fluctuating. The flow conductivity of the hydrophilic quartz sand filter layer fluctuates greatly. In addition, the mechanism of the influence of proppant wettability on the flow-conducting performance is proposed through the microscopic percolation experiment of an oil-water emulsion. This study is of some guiding significance for engineers to better design the surface wettability of proppant and the selection and matching of proppant in hydraulic fracturing construction design to improve the recovery rate of low-permeability reservoirs.

Experimental Study on Enhanced Oil Recovery of Shallow Super-Heavy Oil in the Late Stage of the Multi-Cycle Huff and Puff Process

The shallow, thin super-heavy oil reservoir demonstrates certain characteristics, such as shallow reservoir depths, low-formation temperature, and high crude oil viscosity at reservoir temperatures. In the current production process, the central area of P601 is undergoing high-frequency huff and puff operations, facing certain problems such as decreasing production, low recovery rates, and rapid depletion of formation pressure. Through physical simulation experiments, the various elements of HDNS-enhanced oil recovery technology were analyzed. Nitrogen plus an oil-soluble viscosity reducer can improve the thermal recovery and development effect of super-heavy oil. With the addition of the viscosity-reducing slug, the recovery rate of steam flooding was 58.61%, which was 23.32% higher than that of pure steam flooding; after adding the 0.8 PV nitrogen slug, the recovery rate increased to 76.48%. With the increased nitrogen injection dosage, the water breakthrough time was extended, the water cut decreased, and the recovery rate increased. Nitrogen also plays a role in profile control and plugging within the reservoir; this function can effectively increase the heating range, increase steam sweep efficiency, and reduce water cut. So, the synergistic effects of steam, nitrogen, and viscosity-reducing agents are good. This technology enhances the development of shallow-layer heavy oil reservoirs, and subsequent development technologies are being compared and studied to ensure the sustainable development of super-heavy oil reservoirs.

Superhydrophobic, Conductive and Magnetic Sponge for High Performance Oil-water Separation and Recycled Oil Absorption

Nowadays, the frequent occurrence of oil spills at sea has caused serious pollution to the ecosystem and has led to a gradual decrease in marine resources. Conventional adsorbent materials have difficulty absorbing high-viscosity oils and separating oil from water, and recycling still has great challenges. We developed a novel superhydrophobic, magnetic, and photo-thermal sponge (SMPS) with a simple preparation method, which is composed of polyurethane (PU) sponge, polydopamine (PDA), acidified carbon nanotubes (ACNTs), ferric tetroxide (Fe3O4), and polydimethylsilane (PDMS), modified by self-polymerization, ultrasonication, and soaking. The modification of ACNTs, Fe3O4, and PDMS further enhances the electrical conductivity, magnetism, photo-thermal effect, and superhydrophobicity of the PU sponge. The SMPS (PU/PDA/ACNTs-Fe3O4/PDMS) can reach a water contact angle of 168.32°, which can still be maintained at 150° in harsh environments, and it has a good oil adsorption capacity (up to 31.06g/g) and an oil-water separation efficiency of 96%. In addition, the SMPS has an excellent photo-thermal effect (surface temperature up to 204.9 ℃) for better adsorption of high-viscosity oils. It can also be used for oil adsorption and recycling in local areas through its own magnetism. This paper has studied PU sponges with superhydrophobic, magnetic, and photo-thermal performance, which provides a new research idea for large-scale, regional cleaning and recycling of marine high-viscosity oil pollution.

Research for the Enhanced Oil Recovery Mechanism of Heavy Oil After Composite Huff and Puff Assisted by Edge-Bottom Water Displacement

Abstract In the late stage of exploiting heavy oil reservoirs with edge-bottom water, we are faced with problems such as high crude oil viscosity, channeling of bottom water, and rapid rise in water cut. To clarify the synergistic effect of N2, CO2, N2 foam, and viscosity reducer in water control and oil increase, and solve the problem of edge-bottom water rushing into production wells, one-dimensional sand-pack huff and puff experiments were carried out. First, the N2 foam huff and puff experiment evaluated the effect of N2 foam on controlling bottom water. Then the viscosity reducer-assisted CO2 huff and puff experiment analyzed the synergistic viscosity reduction ability between the two to mobilize the remaining heavy oil. Next, the N2 foam–viscosity reducer–CO2 huff and puff experiment clarified the synergistic effect between the three. Finally, the N2 foam–viscosity reducer–CO2–N2 huff and puff experiment solved the problem of insufficient reservoir energy based on synergistic precipitation and oil increase. Experimental results show that N2 foam–viscosity reducer–CO2–N2 huff and puff is the optimal water control and oil increase solution. This solution can significantly reduce water production and increase oil production. In the one-dimensional sand-pack experiment, this technical solution reduced the water content by 68% and increased the recovery rate by 16.09%. The research results provide a reference for the development of exploitation technology schemes for similar edge-bottom water heavy oil reservoirs after entering high water cut.

An Environmentally Friendly Superhydrophobic Wood Sponge with Photo/Electrothermal Effects Prepared from Natural Wood for All-Weather High-Viscosity Oil-Water Separation.

Rapid industrial development has led to increased crude oil extraction and oily wastewater discharge. Achieving oil-water separation and marine oil adsorption in a cost-effective, efficient, and environmentally friendly manner remains a global challenge. In this work, natural wood was chemically treated to prepare a degradable and environmentally friendly wood sponge structure. In situ polymerization and spraying methods were used to produce an environmentally friendly oil-water separation sponge with superhydrophobic and superoleophilic properties (Fe3O4@P-P@WS). Fe3O4@P-P@WS had excellent superhydrophobicity (WCA = 154.2°) and self-cleaning properties. Additionally, Fe3O4@P-P@WS could convert solar and electrical energy into thermal energy, reaching a surface temperature of 74 °C under sunlight irradiation with an intensity of 1.0 kW m-2. When a voltage of 9 V was applied, the surface temperature reached 120.5 °C. Moreover, under the suction of a vacuum pump or the action of gravity, the continuous separation of highly fluid oil substances was achieved. The designed Fe3O4@P-P@WS offers advantages such as easily obtained raw materials, energy efficiency, simple preparation, and the ability to solve secondary pollution issues, providing a new technology for cleaning organic matter in industrial wastewater discharge and for round-the-clock cleaning of high-viscosity crude oil leaked during offshore oil exploitation.

Comparison of measured and calculated high-viscosity crude oil temperature values in a pipeline during continuous pumping and shutdown modes

The paper investigates the stationary and non-stationary cooling processes of high-viscosity crude oil temperature in the Severnye Buzachi – Karazhanbas pipeline during both pump operations and pump shutdowns. To transport high-viscosity crude oil through pipelines, the hot pumping method is employed. During oil transportation and pump shutdowns, the oil temperature decreases due to heat exchange with the environment, leading to an increase in oil viscosity. As viscosity rises, more power is required from the pumps to move the thickened oil, resulting in higher electricity consumption. To avoid increased operational costs after pump shutdowns, it is crucial to accurately calculate the oil cooling temperature in order to determine the safe shutdown duration and a critical temperature threshold. The Shukhov formula is used to calculate oil temperature during transportation, while a modified version is applied during pump shutdowns. To verify the accuracy of the obtained oil temperature results, the calculated values were compared with the measured values from pipeline sensors in both stationary and non-stationary cases. The novelty of the work is in determining the methodology for calculating the safe shutdown time of a pipeline for high-viscosity oil. The proposed formula was validated using experimental data from SCADA system sensors in real-time.

Preparation of Superhydrophobic and Multifunctional Sponges for Oil/Water Separation and Oil Absorption.

For settling the recycling problem of waste polyurethane sponges (PU) and environment pollution of oil spills simultaneously, this work exploited the multifunctional superhydrophobic PU materials via the dip-coating method, which were prepared by anchoring modified Fe3O4 and expandable graphite (EG) on PU sponges under the adhesion effect of polydimethylsiloxane (PDMS). The water contact angle and sliding angle of as-prepared PU sponges reached 154.1 ± 1.6 and 8°, respectively. Most importantly, the superhydrophobic PU sponges were endowed with the multipath oil treatment ability, which consisted of magnetically driven, gravity-driven, peristaltic pump-driven, and photothermally driven modes. Besides, the light oil absorption capacity, separation flux, and efficiency for superhydrophobic PU sponges reached 23.9 g/g, 27779 L m-2 h-1, and 99.5%, respectively. Owing to the photothermal conversion ability of Fe3O4 and EG, the temperature of superhydrophobic PU sponges was raised to 71.5 °C within 233 s under 1.2 solar irradiation (1200 W/m2), demonstrating its absorption potential for high-viscosity crude oils. In addition, the prepared sponges exhibited good chemical/mechanical stability, self-cleaning, and flame retardancy. In a nutshell, this article has evolved an environmentally benign and practical method for fabricating the multifunctional materials in oil spill treatment, which will efficiently accomplish the targets of low carbon and environmental management.

Development of a demulsifier and technological process study for the preparation of highly viscous heavy oils for refinement

One of the challenges in the petroleum industry is the production of highly viscous heavy oils, often accompanied by undesirable emulsion formation with very high aggregate stability. To prepare the crude oils for refinement, the oils must be destroyed. The destruction of aqueous emulsions containing highly viscous heavy oils is an intricate task owing to the comparatively small disparity in water and oil densities, as well as the high viscosity of the dispersive medium and its high content of mechanical impurities. The problem of the destruction of petroleum emulsions arises desperately during the desalination and dehydration of crude oils with a high content of emulsifiers (resins, asphalts, paraffin, etc.) The creation of a highly efficient demulsifier and the development of an optimal technological process for the preparation of highly emulsifying oils that are distinguished by the composition and quantity of emulsifiers of West Siberian oils, which are widely refined in Russia, are the ways to resolve this challenging and timely issue. This study focuses on the viscous heavy oil of the Verbliouje deposit in the Astrakhan region. It also explains the creation of an effective demulsifier for the destruction of petroleum emulsions characterized by a very high emulsifying power and the fundamental principles of the development of deep dehydration technology and desalination of such high-viscosity heavy oils.

Fundamental study on dielectric oil viscosity for high-performance wire EDM

Dielectric oil has been recently used in wire electrical discharge machining (wire EDM) for achieving high-precision machining. However, the influence of dielectric oil properties on wire EDM characteristics has not been clarified sufficiently. This study fundamentally investigated the influence of dielectric oil viscosity on wire EDM characteristics. In this study, three types of dielectric oil differing only in viscosity were prepared and examined. Linear cutting experiment results showed that the removal rate and the machined surface roughness increase with dielectric oil viscosity. Then, the influence of viscosity on crater removal volume was investigated to discuss the cause of the change in removal rate, and it was found that crater removal volume increases with the viscosity. Furthermore, CFD (computational fluid dynamics) analysis results and discharge observation results showed that the debris exclusion becomes worse in higher viscosity oil, and the discharge concentration occurs frequently, resulting in the deterioration in machined surface roughness. Next, the difference in machining accuracy with dielectric oil viscosity was investigated. It was found that the corner shape accuracy deteriorates with the increase of viscosity while the machined surface waviness and straightness improve slightly. Structural analysis results showed that wire deflection increases with viscosity, resulting in the deterioration in corner shape accuracy. On the other hand, high-speed observation of wire vibration was carried out, and it was found that the wire vibration decreases in the case of higher viscosity, which leads to the improvement in machined surface waviness and straightness.

Importance of Clay Swelling on the Efficacy of Cyclic Steam Stimulation in the East Moldabek Formation in Kazakhstan

Both steam and hot water flooding of high-viscosity oils in the presence of swelling clays are difficult methods for producing oil efficiently because of potential formation permeability reduction. This paper pertains to heavy oil recovery from the East Moldabek formation where the oil API gravity is about 22 and is inundated with swelling clays. To achieve this, we used the IntersectTM reservoir simulator to compare oil recovery economics using both hot water and steam injection as a function of steam cycle duration, temperature, and steam dryness. We also studied clay swelling in the East Moldabek formation where clay poses a significant challenge due to its impact on permeability reduction. In this research, we developed an equation based on experimental data to establish a relationship between water mineralization and permeability in the East Moldabek formation. The equation provides valuable insight on how to mitigate clay swelling which is crucial for enhancing oil recovery efficiency—especially in sandstone reservoirs. Our modeling studies provide the recovery efficiencies for salinities of the hot water EOR versus cyclic steam EOR methods in a formation containing swelling clays. Specifically, the reduction in formation permeability as a function of the distilled water fraction is the controlling parameter in hot water or steam flooding—when the formation water mixture becomes less saline, oil recovery decreases. Our research shows that clay swelling can significantly impact cyclic steam stimulation outcomes, potentially reducing its effectiveness, while hot water flooding may offer a more cost-effective and operationally feasible solution in formations where clay swelling is a concern. Economic analysis reveals the potential for achieving an optimal favorable condition for hot water injection. Therefore, this paper provides a guideline on how to conduct thermal oil recovery for heavy oils in fields with high clay content such as the East Moldabek deposit.

Microbubbles enhance oil-in-water emulsion separation in fibrous coalescers

The principle of fibrous coalescers is to induce the coalescence and growth of small oil droplets in oil-in-water emulsions to achieve oil–water separation. However, they are poorly adaptable to emulsions containing high-viscosity oil. In this study, pressurized air is dissolved in the oil-in-water emulsion, microbubbles are released by reducing the pressure, and the emulsion is subsequently processed through a fibrous coalescer. Adding microbubbles altered the oil removal mechanism within the fibrous bed from oil droplet coalescence and growth to oil droplet–microbubble floc flotation, which significantly improved the emulsion separation efficiency of the fibrous bed, especially in complex emulsions containing surfactants and low salinity. Notably, the decrease in the interfacial energy of the oil droplet–microbubble floc caused oil droplets adhered to fibers to detach and renew quickly. Moreover, the curved interfacial tension increased oil droplet buoyancy and kinetic energy collectively drove the detachment of oil droplets from the fibrous bed. Effective, dynamic anti-fouling of the fibrous bed was able to maintain high throughput during long-term emulsion separation. This study provides a theoretical basis for the industrial application of fibrous coalescers for the treatment of oily wastewater produced during extraction high-viscosity crude oil.

Impact of a compound droplet on a solid surface: The effect of the shell on the core

The dynamic behavior of compound droplets impacting a solid surface was studied via experiments over κ (defined as the ratio of the compound droplet shell thickness h to the diameter D0 of compound droplet) ranging from 0 to 0.34, We ranging from 25 to 325 and Re ranging from 165.3 to 3405.2. The spreading diameter ratio, the maximum spreading dynamic contact angle and spreading speed of the core were investigated. Four modalities of the core of compound droplets were observed on the solid surface, including a) core rebound, b) no rebound, c) core splitting rebound, d) core splitting. The results revealed that the thickness of the shell, We, and the viscosity of the shell have a significant effect on the rebound and spreading processes of the core of the compound droplet. The high viscosity oil shell is conducive to its spreading. As the thickness of the oil shell increases, its cushioning effect on the water core also increases. In addition,κ=0.02254We0.503,κ=-0.336e-We121.056+0.319 and κ=0.06086e-We121.056+0.07716e-We121.70598+0.01595 were used to divide the modal boundary of the compound droplet core. Further analysis reveals the correlation between We, Re, βm and.κ,12+Weβm=8+31-cos22.78+84.57κβm3+0.955We1.05Reβm6.5.

Study on the Effect of Nitrogen Bubble Foam Flooding in Deep Heavy Oil Reservoirs with Edge And Bottom Water

Abstract The oil recovery rate is low, the degree of recovery is low and the water content rises fast after water flooding in deep edge and bottom water heavy oil reservoir in Lukeqin oilfield. In order to explore the method to improve the production effect, the integrated foam system of high temperature and high pressure resistant viscosity reduction and oil displacement is optimized. On the basis of clarifying the mechanism of improving the production effect of nitrogen foam flooding for deep heavy oil, taking the west area of Lukeqin oilfield as the research object, the parameter optimization design of nitrogen foam flooding for deep edge and bottom water heavy oil is carried out, such as injection section plug, gas-liquid ratio and injection-recovery ratio. The optimization results are as follows: the injected nitrogen foam slug is 0.2pv, the gas-liquid ratio is 1-1.2, and the injection production ratio is 1:1. The pilot test of 4 well groups was carried out on the site. After foam flooding, the injection pressure was increased by 5.2mpa, the daily oil production of the oil well was increased by 43T / D, the water cut was decreased by 45%, the accumulated oil production was increased by 32000 tons, and the oil recovery was expected to be increased by more than 10%. The purpose of improving the development efficiency of this type of oil reservoir was achieved. Using this optimization technology for scheme design and field implementation, the oil enhancement effect is remarkable and improves the benefit of deep thick oil development, which can provide technical support for the development of similar domestic reservoirs.

Nickel-cobalt hydrogen phosphate membrane with outstanding anti-crude oil-fouling capability and its microscopic anti-fouling mechanism

Oil/water separation membranes with superior anti-fouling properties against highly viscous oils are crucial for the efficient treatment of oily wastewater. Herein, the effects of functional groups in an inorganic superhydrophilic membrane on the anti-fouling properties of the membrane are investigated. Using a facile one-step electrochemical deposition method, Ni1-xCoxHPO4·3H2O membranes were formed on a Cu(OH)2 microneedle-coated copper mesh (CCNC–P) with superhydrophilic and underwater superoleophobic properties. All CCNC–P membranes with different Co2+ contents showed outstanding anti-fouling capability for oily wastewater such as those containing crude oil. The CCNC–P(x = 0.5) membrane exhibited high separation efficiency reaching 99.7 % across five oil–water mixtures and oil-in-water emulsions, concurrently presenting an ultrahigh flux of 61695 L m−2 h−1 for crude oil–water mixture. Moreover, the membrane consistently maintained its separation performance during the long-term crude oil–water separation process. The flux decline ratio was below 1 %, and the flux recovery ratio approached 99.4 %. The CCNC–P membranes possessed superior chemical, thermal, and mechanical stability, suggesting significant potential for the industrial treatment of oily wastewater. Density functional theory calculation revealed that the HPO42− group in CCNC–P can strongly adsorb water molecules. The resultant stabilized hydration layer impeded the contact between the membrane surface and oil droplets, while the metal ions scarcely influenced the adsorption of water molecules on CCNC–P. These findings provide new insights into the development of novel oil–water separation membranes with higher anti-fouling capabilities against high-viscosity oils.

Oil storage and debrining process in insoluble sediment voids for underground salt cavern energy storage: An experimental study

Large salt cavern oil storage is an effective underground oil storage method, which has been widely used in the United States, Germany, and France. However, the insoluble impurity sediment particles at the bottom of the salt cavern will occupy plenty of oil storage space. To enhance the oil storage capacity, the sediment void oil storage (SVOS) method was proposed. The debrining process from the sediment void prerequisite of the SVOS. It will affect the feasibility of oil injection into the sediment void and the operation efficiency of SVOS. Thus, a self-made debrining device of SVOS was built, and the dynamic debrining process in the sediment void was investigated to explore the debrining process from the sediment void. Six debrining parameters (oil-brine interface change, oil injection rate, brine discharge rate, oil viscosity, the second oil injection quantity, and ground temperature) were proposed and considered. Two kinds of oils (diesel and petrolatum) were conducted in the SVOS debrining experiments. The experimental results showed that the debrining rate remained stable, and it was relevant to the oil injection rate and the interaction of oil and sediments. The average debrining rate of the initial diesel debrining, second diesel debrining, and petrolatum debrining were 2.5 g/s, 2.55 g/s and 2.40 g/s, respectively. The 50 °C of ground temperature sped the debrining rate of high-viscosity oil storage in the sediment void. The oil-brine interface kept balance from the macro perspective, and the oil did not penetrate the inner brine. The oil-brine interface drops ratio of the initial diesel debrining, second diesel debrining, and petrolatum debrining process were 0.586 mm/s, 0.629 mm/s and 0.592 mm/s, respectively. The oil in the sediment voids generated movable and immobile bubbles. The petrolatum flow in the sediment void was easier than the diesel due to the low viscosity at 50 °C. The research has a certain reference value for the development of underground salt cavern oil storage.

Biomimetic structural aerogel derived from green tide enteromorpha-prolifera: Multi-sided unidirectional freeze casting and solar-driven viscous oil spill remediation

The development of environmental remediation materials from renewable biowaste, especially for the cleanup of viscous oil spills in an eco-friendly manner, marks a substantial advancement in functional materials. This study proposes a biomass aerogel (M−MCEP) transformed from Enteromorpha prolifera (EP) in green tides for solar-driven recovery of high-viscosity oil spills. Inspired by the lamella-bridge architecture of Thalia dealbata stems, a biomimetic structure with multi-domain, long-range aligned lamella-bridge interconnections is constructed by a multi-sided unidirectional freeze-casting technique. Multi-scale interface optimization between rigid photothermal fillers and soft lamellar layers achieves multiple reinforcements, providing aerogel with a perfect balance of elasticity and strength. The multidomain low tortuosity channels and photothermal effects enhance M−MCEP’s photothermal conversion (95.2 %) and thermal conductivity (0.3517 W/m·K), reducing oil flow resistance and achieving high oil retention efficiency (>92 %). Under 1 sun irradiation, M−MCEP rapidly heats to 67.3 °C, effectively reducing the viscosity of crude oil in situ, with a crude oil adsorption rate of 1843 mL/m2 within 30 s. Moreover, M−MCEP captures emulsified oil in oil-in-water emulsions through high-speed repeated oscillations, achieving a separation efficiency of 96.42–99.21 %. Renewable resources and unique structural designs provided by nature drive the development of advanced biomimetic aerogels for efficiently remedying catastrophic oil spills.