High Crude Oil Research Articles

Photo/electro-thermal effect, flame retardant, multifunctional durable superhydrophobic sponge for all-weather recovery high viscosity crude oil and photothermal defrosting/deicing

Developing functional adsorption materials that efficiently adsorb high viscosity oil is crucial for solving oil spill accidents. Herein, low-density three-dimensional porous melamine sponge was used as the modified substrate. First, phytic acid is selected for modification to make it flame retardant. Then, polypyrrole (PPy) and hexadecyltrimethoxysilane (HDTMS) are modified on its surface through low-temperature polymerization and impregnation, ultimately obtaining a multifunctional durable superhydrophobic PA/PPy/HDTMS@MF (melamine foam) sponges with photo/electro-thermal effects and flame retardant. When the applied voltage is 10 V, the core temperature on the PA/PPy/HDTMS@MF sponge’s surface rapidly increases from 26.4 °C to 134.6 °C within 80 s, and the sponge will not burn and be damaged. Under the irradiation of one sunlight (1 kW/m2), the surface core temperature can rapidly rise from 26.4 °C to 93 °C within 70 s. The superhydrophobic PA/PPy/HDTMS@MF sponge can all-weather absorb kinds of high viscosity crude oil and solid oils that are 18–27 times than its own mass, indicating that the prepared superhydrophobic sponge has excellent oil collection performance. And under one sunlight (1 kW/m2), after 10 cycles of desorption, the prepared superhydrophobic sponge can still absorb 26 times more crude oil than its own weight. In addition, PA/PPy/HDTMS@MF sponge also has the characteristic of photothermal defrosting and deicing, and the ice on its surface can begin to melt within 5 min under one sunlight (1 kW/m2). The melted water will not enter the inside of the sponge, effectively ensuring the utilization efficiency of photothermal effects. Based on the above advantages, the prepared photo/electro thermal conversion superhydrophobic sponge has excellent development prospects in the field of high viscosity oil adsorption and photothermal defrosting/deicing.

Researching Offshore Facilities and Choosing an Appropriate Platform for Hydrate Extraction in the Bay of Bengal

Offshore buildings are used in various locations and sea depths for several reasons. Different equipment, platforms, and design techniques are needed depending on water depth, climatic conditions, structural arrangement, and new concepts. Offshore constructions usually generate and transport oil, gas, and other commodities. Bangladesh has yet to use the Bay of Bengal's hydrocarbon potential for oil and gas. Bangladesh lags behind India and Myanmar in maritime oil and gas discovery. In 50 years, Bangladesh's sea barriers have yielded no benefits. Bangladesh's economy is hindered by its high crude oil imports. Focus on offshore petroleum exploration to locate "black gold" now. Therefore, an offshore structure is needed. This thesis paper covers the fundamentals of all offshore systems, broadens the research, and recommends appropriate platforms for various sea-water depths, which those platforms are meant to be built for hydrates predicted in the Bay of Bengal. The paper uses the Bay of Bengal sedimentation and estimated water depth to choose offshore constructions. The country's maritime boundaries have 26 oil and gas blocks. There are 11 in shallow water and 15 in deep sea. According to statistics, the blocks are on the continental shelf and deep-water region. Five zones make up the Bay of Bengal continental shelf. They are shores A-B, B-C, C-D, D-E, and E-F after region F continental slope continues till the deep sea area. The continental slope zone C-D has 64-106 m water depth. Therefore, the Bay of Bengal continental shelf is suitable for all permanent offshore buildings except this zone. Only concrete gravity platforms fit this zone. We need the technology to search for oil and gas in water. It takes a lot of work to get foreign companies to work together. Thus, skilled people should work on it and encourage government or private businesses to develop oil and gas production technology.

Laboratory Test of Fluid Physical Property Parameters of Well Fluid Containing CO2

Change regulation of the physical properties of fluid is key to accurately predicting multiphase fluid flow in the production wellbore of CO2 flooding reservoirs. Given the characteristics of significant changes in pressure, temperature, and CO2 content in the whole wellbore of production wells in CO2 flooding reservoirs, this paper systematically studied the change rules of volume factor, viscosity, density, and solubility of well fluid for pressure 5~30 MPa, temperature 20~120 °C, and CO2 content 10~90% through single degassing PVT experiments. According to the experimental results, the volume factor of crude oil increases first and then decreases with the pressure increase. At the bubble point pressure (20 MPa), the volume factor of crude oil can reach 1.89 at high temperatures. The volume factor can be increased from 1.28 to 1.44 at 8 MPa when the temperature increases from 20 °C to 120 °C. Under the bubble point pressure, the increase in pressure increases the solubility of CO2, and the viscosity of crude oil decreases rapidly. In contrast, above the saturation pressure, the increase in pressure increases the viscosity of crude oil. Under the freezing point temperature (24 °C), the viscosity of crude oil decreases sharply with increase in temperature. In contrast, above the freezing point temperature, the viscosity change of crude oil is not sensitive to temperature. The wellbore temperature has a significant impact on the density of the well fluid. At 5 MPa, the temperature increases from 20 °C to 120 °C, which can reduce the density of high CO2 crude oil from 0.93 g/cm3 to 0.86 g/cm3. The solubility of CO2 in crude oil is sensitive to pressure. When the pressure increases from 5 MPa to 15 MPa at 20 °C, the solubility increases by 36.56 cm3/cm3. The results of this paper support the multiphase fluid flow law prediction of CO2 flooding production wells with a high gas–liquid ratio.

Isolation, identification, and screening of biosurfactant-producing and hydrocarbon-degrading bacteria from oil and gas industrial waste

Qatar is one of the biggest oil and gas producers in the world, coupled with it is challenging environmental conditions (high average temperature: >40 °C, low annual rainfall: 46.71 mm, and high annual evaporation rate: 2200 mm) harbors diverse microbial communities that are novel and robust, with the potential to biodegrade hydrocarbons. In this study, we collected hydrocarbon contaminated sludge, wastewater and soil samples from oil and gas industries in Qatar. Twenty-six bacterial strains were isolated in the laboratory from these samples using high saline conditions and crude oil as the sole carbon source. A total of 15 different bacterial genera were identified in our study that have not been widely reported in the literature or studied for their usage in the biodegradation of hydrocarbons. Interestingly, some of the bacteria that were identified belonged to the same genus however, demonstrated variable growth rates and biosurfactant production. This indicates the possibility of niche specialization and specific evolution to acquire competitive traits for better survival. The most potent strain EXS14, identified as Marinobacter sp., showed the highest growth rate in the oil-containing medium as well as the highest biosurfactant production. When this strain was further tested for biodegradation of hydrocarbons, the results showed that it was able to degrade 90 to 100% of low and medium molecular weight hydrocarbons and 60 to 80% of high molecular weight (C35 to C50) hydrocarbons. This study offers many promising leads for future studies of microbial species and their application for the treatment of hydrocarbon contaminated wastewater and soil in the region and in other areas with similar environmental conditions.

Explaining intraday crude oil returns with higher order risk-neutral moments

High frequency crude oil option data is used to extract the higher order risk-neutral moments from the crude oil market. These risk-neutral moments include the variance, third central moment and the recently developed tail risk variation measures. We find it is beneficial to disaggregate these risk-neutral moments into their semi-moments, and to work with their log differences instead of the level. The log differences of the second and third semi-moments, and to a lesser extent, the log differences of the tail risk measures, are found to explain returns in the crude oil and S&P 500 futures at high frequency. We also provide evidence that the efficient market hypothesis holds at high frequency in these markets.

Robust 3D porous superhydrophobic foam with excellent photothermal effect and Joule heating effect for efficient all-weather cleanup of highly viscous crude oil spills

Crude oil spill is difficult to deal with and still a global challenge due to its high viscosity. Developing foams with excellent mechanical properties, photothermal effect and Joule heating effect simultaneously to achieve crude oil all-weather recovery is desirable. Here, 3D porous foams were successfully fabricated by the composite of polydimethylsiloxane (PDMS) and multi-walled carbon nanotubes (MWCNT) by a combination of sacrificial template method and laser etching treatment. Benefiting from the low surface energy of PDMS itself and the micro-nano structures constructed in the preparation, the obtained foams exhibit excellent superhydrophobic and superoleophilic properties (WCA of 157° and OCA of 0°). Significantly, MWCNT do not exist as a coating around the foam surface, but as the main component constituting the foam skeleton, so the foam shows excellent mechanical property, low temperature resistance, high temperature resistance, salt resistance and abrasion resistance. Moreover, taking the advantage of the addition of MWCNT, the foam shows excellent photothermal effect requiring 1 sun irradiation to attain a temperature of 60.7 ℃ after 4 min and a stable temperature of 71.6 ℃ after 10 min, and Joule heating effect requiring only 9 V voltage to attain a temperature of 64.5 ℃ after 1.5 min and a stable temperature of 91.1 ℃ after 10 min, respectively. Besides low viscosity oil–water separation, it can achieve rapid crude oil spill recovery under the photothermal effect or Joule heating effect. The combination of the two effects can realize the coupling effect and achieve high-efficiency all-weather high viscosity crude oil recovery, thus making the foam more practical. This foam is expected to be an ideal material for all-weather dealing with oil spills.

A Novel Thermal Analysis Method Based on a Multi-Physics Two-Way Coupled Method and Its Application to Submersible Permanent Magnet Synchronous Motors

As a submersible permanent magnet synchronous motor (SPMSM) must function in downhole high temperature crude oil for long periods of time, the accurate prediction of its temperature rise is crucial to improve the stability of the motor. However, the analysis of its temperature field involves multiple physical fields, such as the electric field, the magnetic field, the fluid field and so on, and it is difficult to calculate accurately. Motor loss is usually loaded as a fixed value when calculating the temperature field, while in reality, the loss always changes with temperature. Therefore, the calculation of temperature is inaccurate using this one-way coupled method. In this paper, the relationship between loss and temperature is investigated and an electromagnetic-thermal fluid multi-physics two-way coupled analysis method suitable for SPMSM is proposed. The loss can be loaded as a variable by this new two-way coupled method, which significantly improves the temperature calculation accuracy. In order to prove the feasibility of the two-way coupled method, experiments based of a prototype of high torque and low speed SPMSM and cavity pump are conducted with the fiber Bragg grating (FBG) sensor measuring SPMSM temperature. Finally, the multi-physics two-way coupled method proposed in this paper is proven to be rational and feasible in the analysis of the SPMSM temperature rise.

Extreme time-varying spillovers between high carbon emission stocks, green bond and crude oil: Evidence from a quantile-based analysis

This paper combines quantile regression with time-varying vector autoregressive (TVP − VAR) model to study extreme spillover effects among high carbon emission stocks, green bond and WTI crude oil from April 21, 2010 to March 25, 2022. The results display a static total spillover index of approximately 49% at the conditional mean and conditional median estimates; while about 83% under the left tail and right tail estimates. The quantile-based spillover model is better than the mean-based one, because the former better captures the risk contagion mechanism under extreme market conditions. In addition, under extreme market conditions, green bond and WTI crude oil are net receivers of systemic shocks, while the remaining markets analyzed are net transmitters. The connectedness is time-varying in all cases, but the tail is less volatile. The analysis of relative tail dependence suggests the existence of asymmetric behavior, which implies different spillover effects in bullish and bearish markets. In addition, the European sovereign debt crisis has a much larger impact on spillovers under bearish markets than under bullish markets.

Advances in special wettable materials for adsorption separation of high-viscosity crude oil/water mixtures.

Effective separation of highly viscous crude oil/water mixtures remains a worldwide challenge. Employing special wettable materials with adsorptive properties as an emerging separation strategy has attracted extensive attention in the treatment of crude oil spillage. Such a separation technique combines excellent wettability materials and their adsorption performance to achieve energy efficient removal or recovery of high viscosity crude oil. Particularly, special wettable adsorption materials with thermal properties provide novel ideas and directions for the construction of rapid, green, economic and all-weather crude oil/water adsorption separation materials. Negatively, the high viscosity of crude oil makes most special wettable adsorption separation materials and surfaces extremely susceptible to adhesion and contamination in practical applications, leading to rapid functional failure. Moreover, such an adsorption separation strategy towards high-viscosity crude oil/water mixture separation has rarely been summarized. Consequently, there are still some potential challenges in separation selectivity and adsorption capacity of special wettable adsorption separation materials which urgently need to be summarized to guide the future development. In this review, the special wettability theories and construction principles of adsorption separation materials are first introduced. Then, the composition and classification of crude oil/water mixtures, particularly focusing on enhancing the separation selectivity and adsorption capacity of adsorption separation materials, are comprehensively and systematically discussed via regulating surface wettability, designing pore structures and reducing crude oil viscosity. Meanwhile, the separation mechanisms, construction ideas, fabrication strategies, separation performances, practical applications, and the advantages and disadvantages of special wettable adsorption separation materials are also analyzed. Finally, the challenges and future prospects for adsorption separation of high-viscosity crude oil/water mixtures are expounded.

Scalable fabrication of efficient and recycling wood residue-derived sponge for crude oil adsorption

Fast, low-cost, and efficient technology for crude oil remediation is a challenge. Herein, we reported a wood residue-derived sponge immobilized with Fe 3 O 4 nanoparticles (NPs) via the delignification, high-speed dispersion and freeze-drying processes, which allows fast and efficient cleanup of crude oil spill with the assistance of solar irradiation. Magnetic wood residue-derived sponge (M-sponge) with uniformly distributed Fe 3 O 4 NPs exhibits excellent photothermal conversion effect and can adsorb 172.62 g g -1 of crude oil in the first 15 minutes. Meanwhile, the M-sponge with good magnetic property is easily recycled by an external magnet and keeps high crude oil uptake of 154 g g -1 at least 10 adsorption-desorption cycles. Combining with the light weight (9 g m -3 , porosity > 91%), none harmfully hydrophobic chemicals, synthesis simplicity, and abundant starting materials, M-sponge design represents a high-value utilization based on forestry waste in the field of crude-oil remediation and water treatment. • A solar-assisted self-heating magnetic sponge adsorbent is constructed. • M-sponge with high photothermal conversion efficiency exhibits the adsorption capacity up to 172.62 g g -1 for crude oil. • M-sponge can be recovered by magnet and shows adsorption attenuation less than 11% after 10 times recycling. • Without toxic chemical reagents addition, the raw materials are sustainable, abundant and low-cost.

Analysing the rising oil price shock driven by Russia-Ukrainian tensions - effect on inflationary pressure in South Africa

Objective – The aim of this paper is to examine the relationship between the CPI, the brent crude oil price, and the PPI for final manufactured goods as well as the Rand/Dollar exchange rate during the past year. The study used South Africa as a proxy for developed countries. The objective is, therefore, to evaluate the effects of the increase in commodity prices on inflation and other macroeconomic variables. Methodology –The study utilised a quantitative methodological approach through the assessment of an econometric model that employed monthly data from January 2017 to May 2022. The paper utilized variables such as CPI, brent crude oil prices, PPI for final manufactured goods as well as the Rand/Dollar exchange rate. Findings – Short- and long-run relationships were established between the variables using the vector error correction model (VECM) and the Johansen co-integration equation methods. The long-run conclusions showed that high brent crude oil prices, high sunflower oil, a depreciating exchange rate and increasingly high PPI levels will lead to an increase in the CPI (Inflation). The results also indicated that oil prices still influence the basic prices of goods and services since all things need to be transported. Novelty – The results of the study showed that a perpetual international and national macro-economic environment is crucial to prevent inflationary pressures and price shocks, while volatile exchange rates unsteady PPI’s and significantly high oil and commodity prices causes cost-push inflation. Policy certainty and political stability is important to keep inflation stable and economic growth positive, which could lead to a more self-sufficient economy which are is reliant on political instability as an obstacle for positive future economic growth. Type of Paper: Empirical JEL Classification: E31, E37, E60, E63 Keywords: Russian-Ukrainian conflict, economic growth, Brent crude oil prices, PPI, CPI, exchange rates, sunflower oil. Reference to this paper should be made as follows: Neethling, J.R; Wyk, A.S.V. (2022). Analysing the rising oil price shock driven by Russia-Ukrainian tensions - effect on inflationary pressure in South Africa, J. Bus. Econ. Review, 7(3), 178–193. https://doi.org/10.35609/jber.2022.7.3(3)

Analyzing the rising oil price shock driven by Russia-Ukrainian tensions - effect on inflationary pressure in South Africa

At the onset of 2022 the Russian Federation occupied Ukraine in a major intensification of the Russo-Ukrainian War that instigated in 2014. The result of the Russians invasion in Ukraine caused a major intensification in the inflationary levels and weakened global economic growth. As a result of the conflict the Brent Crude Oil prices increased from $92.98 per ounce on 24 February to $122.43 per ounce on the 8th of June 2022 which is an increase of 31.67 per cent in less than 4 months. The result of this invasion reformed the macroeconomic environment which fundamentally affected the international commodity markets and consequently leading to insufficient financial linkages between Russia and the rest of the World. The aim of this paper is to examine the relationship between the CPI, the brent crude oil price, the PPI for final manufactured good as well as the Rand/Dollar exchange rate. The study used South Africa as a proxy for developed countries. A quantitative methodology was used through the estimation of an econometric model by utilizing monthly time series data from January 2017 to May 2022. The CPI was chosen as the dependent variable while the independent variables included the PPI, sunflower oil, Rand/Dollar exchange rate and the brent crude oil. Short- and long-run relationships were established between the variables using the vector error correction model (VECM) and the Johansen co-integration equation methods. The long run conclusions showed that high brent crude oil prices, high sunflower oil, a depreciating exchange rate and increasingly high PPI levels will lead to an increase in the CPI (Inflation). In conclusion, the results of the study showed that a perpetual international and national macro-economic environment is crucial to prevent inflationary pressures and price shocks, while volatile exchange rates unsteady PPI's and significantly high oil and commodity prices causes cost-push inflation. Policy certainty and political stability is important to keep inflation stable and economic growth positive, which could lead to a more self-sufficient economy which are not reliant on political instability as an obstacle for positive future economic growth. Keywords: Russian-Ukrainian conflict, economic growth, Brent crude oil prices, PPI, CPI, exchange rates, sunflower oil.

Superhydrophobic aerogel blanket with magnetic and solar heating effect enables efficient continuous cleanup of highly viscous crude oil

Rapid cleanup of highly-viscous oil spills the sea is eagerly desired while still remains a great challenge. Hydrophobic and lipophilic adsorbents are regarded as ideal candidate for oil spill remediation. However, traditional adsorbents are not suitable for viscous crude oil, which would block the porous structure and lead to poor adsorption efficiency. In this work, a non-contact responsive superhydrophobic SiO2 aerogel blankets (SAB) with excellent magnetic and solar heating effect for efficient removal of viscosity oils under harsh environments was developed, via assembled MXene and Fe3O4/polydimethylsiloxane layer-by-layer along the SAB skeleton (Fe3O4/MXene@SAB). The Fe3O4/MXene@SAB exhibited excellent compression tolerance (compression stress 70.69 kPa), superhydrophobic performance (water contact angle 166°), and corrosion resistance (weak acid/strong base). Due to high water repellency and stable porous structure, the Fe3O4/MXene@SAB could successfully separate oil-water mixture, while with remarkable separation flux (1.50–3.19 × 104 L m−2 h−1), and separation efficiency (99.91–99.98 %). Furthermore, the responsive Fe3O4/MXene@SAB also showed outstanding magnetic-heating and solar-heating conversion efficiency, which could continuously separate high viscosity crude oil from seawater by pump even under relatively low magnetic fields and mild sun. The superhydrophobic blankets hold great promise for efficient treatment of heavy oil spills.

Superhydrophobic polyurethane sponge for efficient water-oil emulsion separation and rapid solar-assisted highly viscous crude oil adsorption and recovery

Rapid and efficient cleaning of oily wastewater and high viscosity crude oil spills is still a global challenge. Conventional three-dimensional porous adsorbents are ineffective for oil-water separation in harsh environment and are restricted to the low fluidity of high viscosity crude oil at room temperature. Increasing temperature can enormously improve the fluidity of viscous crude oil. Herein, the polydimethylsiloxane (PDMS) /carbon black (CB) -modified polyurethane sponge (PU) were prepared by a simple one-step dip-coating method. PDMS/CB@PU (PCPU) exhibits high adsorption capacity to various oils and organic liquid (28.5–68.7 g/g), strong mechanical properties (500 cycles at 50%), outstanding reusability (100 cycles of adsorption and desorption) and excellent environmental stability due to the special PDMS/CB coating. The maximum surface temperature of PCPU sponge can reach 84.7 ℃ under 1 sunlight irradiation. Therefore, the PCPU sponge can rapidly heat and enhance the fluidity of viscous crude oil, significantly speeding up the viscous oil recovery process with the maximum adsorption capacity of 44.7 g/g. In addition, the PCPU sponge can also combine with the vacuum pump to realize the continuous and rapid repair of viscous oil spills from the seawater surface. In consideration of its simple preparation, cost-effectiveness and high oil absorption ability, this solar-assisted self-heating adsorbent provides a new direction for large-scale cleanup and recycling of viscous crude oil spill on the seawater surface.

The Effects of Combination of Steam Flooding, CO2 and Cyclic Steam Stimulation Injection Pilot Test in Heavy Oilfield in Sudan

Applications of Enhanced Oil Recovery (EOR) are highly required and needed in Sudan to keep oil supply at stable levels. ”FUL” Oilfield in Sudan has shallow reservoir affected by big boundary and bottom water drive with high crude oil viscosity. This research, through a comprehensive analysis of the current producing wells, perforation intervals, CO2 temperature analysis, steam parameters optimization which using two approaches (deterministic and stochastic) were analyzed, using a combination of continues steam flooding, CO2 assisted steam flooding, and cyclic steam stimulation in the pilot test sector. CMG-STARS and CMOST AI simulators software was used in this study. By determining recovery factor (RF) as objective function. It could conclude that: CO2 assisted steam flooding even it could decrease the water cut, but its effect to increase the oil recovery factor is not considerable. Continuous steam flooding has the best oil recovery from these three methods.

A super-hydrophilic and underwater super-oleophobic membrane with robust anti-fouling performance of high viscous crude oil for efficient oil/water separation

In recent years, crude oil-spill accidents released millions of tonnes of crude oil into the environment worldwide. Oily wastewater has persistent harmful influences on the marine environment and animal health. It is essential to dispose of crude-oil contained wastewater. The high adhesion of crude oil is easy to adhere to the surface of separation materials, and traditional separation equipments always become invalidation when used for treating the oily wastewater containing crude oil. To solve this problem, we have successfully prepared super-hydrophilic chitosan hydrogel coated metal mesh (CS-SSM) via a simple coating method and the cross-linking reaction of chitosan and glutaraldehyde, which exhibits robust anti-high viscous crude oil-fouling performance. The super-hydrophilic CS-SSM showed excellent separation performance for various oil/water mixtures, and the separation efficiency and flux for the high viscous crude oil/water mixture exceed 99.99% and 12,000 L·m−2·h−1 respectively. Moreover, the molecular dynamics simulation clarified that the chitosan hydrogel coating the surface of metal mesh can dramatically decrease the interaction between crude oil molecules and metal mesh, resulting in the robust anti-high viscous crude oil-fouling performance for CS-SSM. In addition, the oil skimmer fabricated with the super-hydrophilic CS-SSM was demonstrated to effectively deal with large-area spills of crude oil.

A solar-driven self-repairing sponge for efficient recovery of crude oil

Solar-heated absorption has become an effective technique to handle the crisis of crude oil spill. Although photothermal absorbents could efficiently clean up crude oil in situ, oil recovery methods such as squeezing absorbents have a negative impact on structural integrity and performance of absorbents, shortening the service life of the device. Herein, a solar-driven carbon-doped self-repairing polyurethane sponge (CSPU) is fabricated for absorption and recovery of crude oil. Chitosan-derived N-doped porous carbon (NPC) as photothermal filler and 2-hydroxyethyl disulfide (HDES) as chain extender are introduced into sponge in situ through free foaming. The firm load of NPC endows CSPU with good light absorption of 97.1% and a stable photothermal conversion performance. Additionally, the solar-driven self-repairing property promotes CSPU to timely repair the structural damage caused in oil recovery process. Consequently, CSPU exhibits a high crude oil absorption of 23.5 g/g, and it still maintains a good oil absorption and recovery efficiency after friction, ultrasonic treatment or multiple absorption-recovery cycles. This strategy combining photothermal oil absorption and solar-driven self-repairing provides a sustainable and durable solution for addressing crude oil spills.

Mechanistic investigation of using optimum saline water in carbonate reservoirs low asphaltenic crude oil with high resin content: A carbonate-coated microfluidic study

Many mature reservoirs around the world have entered the second period of their life and their production rates are going to decline. In addition, after producing from the reservoir at the primary and secondary stages more than 50 percent of hydrocarbons would remain in place. Therefore, it is essential to find a suitable method to increase oil recovery in the tertiary stage. In recent two decades, smart water or low saline water (LSW) flooding has been introduced as a dominant method, especially on wettability alteration from oil-wet to water-wet or neutral wet conditions, which is leading to more oil production. On the contrary, there are an inadequate number of researches on low asphaltenic crude oil with high resin content in water flooding. In this type of crude oil, the role of asphaltene in changing the wettability and reducing the interfacial tension (IFT) is not as great as the other surface active agents of crude oil. Hence, the role of each ion and its synergism with the surface active agents of crude oil may be different from previous studies. The fluid–fluid and rock-fluid interactions between diluted seawater and a low asphaltenic crude oil were investigated by performing different types of experiments, such as pendant drop IFT measurement tests, sessile drop contact angle (CA) measurement experiments, zeta potential analysis, and pH determination. In the next step, the impact of ten different salts on reducing the interfacial tension, and wettability alteration was determined to show the underlying mechanisms of optimum brine based on the same ionic strength (IS). Finally, some microfluidic tests were utilized in a carbonate-coated micromodel to show the confirmation of previous results in porous media visually and determine the fluid–fluid and rock-fluid interactions on the recovery factor (RF). Based on IFT and CA results, the optimum brine was seawater (SW) that could reduce the IFT from 21.13 to 16.21 mN/m and change the CA from 137° to 46° (Δϴ = 91°). Due to the lower asphaltene content in such crude oil, the presence of Na+ with SO42-, and Mg2+ with Cl- plays a significant role in IFT reduction by creating a synergistic effect between these ions with a high fraction of resin. Na2SO4 and MgSO4 reduce the IFT from 21.13 to 6.21 and 8.46 mN/m, respectively due to the existence of the high amount of Mg and SO4 in aqueous solution which has a considerable effect on fluid–fluid interaction. Also, Mg2+ and SO42- can obtain 89° wettability alteration (Δϴ) and provide a water-wet condition (ϴ = 48°) because of the synergistic of the presence of divalent anions and cations through the solution and the presence of high resin content that leads to excellent wettability change. Additionally, Na2SO4 can change the contact angle from 137° to 67° (Δϴ = 70°). Although the greatest impact of single salts on IFT reduction and wettability alteration was obtained by Na2CO3 and NaHCO3 because of saponification and pH elevation; however, the concentration of these salts in SW was negligible. Thus, the main salts for fluid–fluid and rock-fluid interactions in SW/low asphaltenic crude oil/calcite systems were Na2SO4, MgSO4, and MgCl2. Moreover, due to the presence of Na+, Mg2+, and SO42- in SW, the wettability of the pore surface was altered from oil-wet to water-wet during SW flooding in the micromodel. Furthermore, reducing the IFT and changing the wettability lead to decreasing the capillary number and delay in breakthrough (BT) time, which consequently improved the oil recovery from 25.42 % (DIW flooding) to 46.59 %. The findings of this study can help for a better understanding of the effect of low asphaltenic with high resin crude oil and ions on the fluid–fluid and rock-fluid interaction through porous media at static and dynamic conditions in order to increase the final oil recovery.

Robust PAAm-TA hydrogel coated PVDF membranes with excellent crude-oil antifouling ability for sustainable emulsion separation

Hydrogel coating was widely studied in the field of oil/water separation due to its underwater superoleophobic performance, which could avoid the blockage of the separation membrane by oil effectively, especially high viscosity crude oil. In this manuscript, a layer of ultra-thin Polyacrylamide-Tannic (PAAm-TA) hydrogel coating was coated on the surface of PVDF microfiltration membrane by a simple immersion process, which could endow it with superhydrophilic and underwater superoleophobic performance. Due to the outstanding superhydrophilic and ultrathin hydrogel coating, the obtained sample showed an ideal emulsion separation efficiency and flux, 99.47% and 1184.3 L/(m2 h bar) for toluene-in-water emulsion. Additionally, the residual crude oil on the membrane surface can be easily and quickly removed by rinsing with water. Attributed to a variety of chemical and hydrogen bonding and negatively charged groups on the tannic acid molecules, the membranes possess good mechanical stability and electrostatic adsorption properties. The obtained PVDF/PAAm-TA membrane could maintain its special wettability in a wide range of chemical environments, enabling it great potential to be used in complex water treatment. In summary, this study will provide new insights into a new idea and method for the preparation of hydrogel coated porous materials for oil/water separation.

Enhanced Crude Oil Sorption by Modified Plant Materials in Oilfield Wastewater Treatment.

The treatment of oilfield wastewater with high crude oil content and complex composition is a problem requiring considerable attention. In order to effectively remove crude oil contained in wastewater, in this work, rice straw, as an oil-absorbing material, was modified and used as a sorbent for crude oil. Rice straw was modified with alkali and cetyltrimethylammonium chloride (CTAC) by simple substitution reaction. The adsorption capacity of modified rice straw for oil was evaluated. The results illustrate that the adsorption rate of rice straw for crude oil was increased from 0.83 to 8.49 g/g, with the optimal conditions of 18% NaOH reacted for 90 min at 50 °C and 2% CTAC reacted for 60 min at 20 °C. The proposed modification method could be used for different materials to enhance the adsorption rate. The results of the contact angle test show that the modified straw changed from hydrophilic to hydrophobic, which may be the main reason for the improvement in the oil absorption rate. Finally, the surface structure of rice straw was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR) and N2 adsorption-desorption isotherms, which further confirmed the hydrophobicity of the modified rice straw.