Search

Flue gas flooding has been applied in many oilfields for its accessibility and low cost. However, the problem of gas channeling during flue gas flooding is significantly more serious due to reservoir heterogeneity and gravity override, and the traditional profile control agent is inapplicable because of flue gas acidity. In order to solve this challenge, a novel acidic nanoparticle was presented first; then, the profile control performance of both water slugs and this novel nanoparticle for flue gas flooding in heterogeneous reservoirs was studied using core samples with different rhythms. The results show that the stability of the acidic nanoparticles is good, and the viscosity of the nanoparticle solution increases as the pH decreases, which is suitable for acidic flue gas flooding. The oil recovery of flue gas flooding in a positive rhythm core is 5–10% greater than that in a reverse rhythm core. The water slug can improve oil recovery by 5% in the reverse rhythm core, and oil recovery was less than 2% in the positive rhythm core. The effect of a nanoparticle slug is much better than the water slug. It improved the oil recovery by 10% in the positive rhythm core by continuing flue gas flooding after nanoparticle slug treatment, which was more than the 20% in the reverse rhythm core. The ultimate oil recovery of both positive and reverse-rhythm cores by acidic nanoparticle slug treatment was around 50%, which was 10% greater than the water slug treatment. The conformance control using acidic nanoparticles is more suitable for reverse rhythm formation due to its plugging capacity, deformation characteristic, and viscosity increment in an acidic environment. This research demonstrated that these novel acidic nanoparticles could be effectively applied to conformance control during flue gas flooding in heterogeneous reservoirs. [ABSTRACT FROM AUTHOR]

In view of the problems of low matrix permeability and low oil recovery in shale reservoirs, CO2 huff and puff technology is considered as an effective method to develop shale oil reservoirs. However, the production behaviors of actual shale reservoirs cannot be reproduced and the EOR potentials cannot be evaluated directly by scaled models in the laboratory. Conventional CO2 huff and puff has problems such as early gas breakthrough and gas channeling leading to inefficient development. In this article, with the help of a three-dimensional experimental simulation apparatus, a new method of CO2 huff and puff with a horizontal well assisted by pumping production and water injection disturbance is developed. The dynamic characteristic, pressure field distribution of soaking and the enhanced oil recovery effect are comprehensively evaluated. The results show that the soaking stage of CO2 huff and puff can be divided into three stages: differential pressure driving, diffusion driving and dissolution driving. According to the pressure field distribution, after water injection disturbance, the fluctuation boundary and distribution of pressure becomes more stable and uniform and the sweep rate is greatly improved. Water injection disturbance realizes the combination of CO2 injection energy enhancement and water injection energy enhancement and the CO2 injection utilization rate is improved. It has the dual effect of stratum energy increase and economic benefit. The new huff and puff method can increase the oil recovery rate by 7.18% and increase the oil–gas replacement rate to 1.2728, which confirms the potential of horizontal well pumping production and water injection disturbance-assisted CO2 huff and puff technology to improve oil recovery. [ABSTRACT FROM AUTHOR]

Liquid metals have been expected to be promising photothermal/electrothermal anti-icing materials for their excellent electrical and thermal conductivity. However, inescapable oxidation and corrosion limit the life and efficiency of liquid metal materials. Inspired by the self-assembly of phospholipid molecules in cell membranes, self-assembly corrosion resistant liquid metal composite coating is designed to protect liquid metal from icing and corrosion hazards. Based on self-assembly of fluor‑silicon molecules mimicking phospholipid molecules and micro-nano surface morphology, the coating has water contact angle of 150.8°and icing delay time of 497 s, which is 4.21 times that of unmodified liquid metal. Under the combined action of 80.5 °C photothermal effect and superhydrophobicity, the de-icing efficiency of the coating is 2.04 times that of the unmodified liquid metal. The photothermal de-icing efficiency remains 99.3 % after two months of acid corrosion and 94.4 % after two months of alkali corrosion. In addition, the thermal network of the coating leads to thermal conductivity of 3.66 W/mK and flame retardancy with UL94 at V0 rating. The coating is made into an electrothermal device with 52.5 °C heating temperature and rapidly de-icing property. The cell membrane-inspired self-assembly liquid metal composite coating provides a secure solution for long-term photothermal/electrothermal anti-icing/de-icing in exposed environment. [Display omitted] • The FLM coating has photothermal/electrothermal anti-icing/de-icing performance. • The FLM coating has oxidation and corrosion resistance. • Inspired by cell membrane, a self-assembly encapsulated structure is designed. • The self-assembly compact fluor-silicon shell protects the liquid metal. • The FLM nanoparticles provide superhydrophobicity. [ABSTRACT FROM AUTHOR]

The dissolution of CO 2 into formation brine, one of the dominant trapping mechanisms for geological carbon storage (GCS) in deep saline aquifers, has been widely investigated. Most experimental and modeling studies focused on the CO 2 solubility in synthetic brines. However, rare studies have been performed to investigate CO 2 solubility in real formation brines, especially when ion-ion interactions were considered. In this work, the CO 2 solubility of seventy formation brines from major basins in China including the Junggar basin, Ordos basin, and North and South Songliao basin was measured at in-situ pressure and temperature conditions. Experimental results show that CO 2 solubility has a strong relationship with pressure and total dissolved solids (TDS), while the relationship between solubility and temperature is weak. Three solubility regions were classified in terms of depth. In Regions I and III, CO 2 solubility increases with depth and is independent with depth in Region II. However, the effect of salinity on CO 2 solubility was observed in all regions. Additionally, a modified Duan's model used for a mixed-salt system was proposed using dataset from this study and literature. Comparisons with Duan's model for CO 2 solubility in mixed-salt systems show the average absolute relative deviation equals 5.14%, which reveals a clear improvement in the modified model. In addition, the validation of the model was performed, and results show that the average absolute relative deviation before and after improvement are 12.10% and 5.11%, respectively, indicating the high accuracy of the improved model. Overall, this research improves the understanding of CO 2 solubility in real formation brines and illustrates the efficiency and accuracy of the modified model, which is crucial for the evaluation of the CO 2 storage capacity, fate of CO 2 over storage site life for commercial GCS projects. [ABSTRACT FROM AUTHOR]

Capturing CO 2 using natural carbonic anhydrase (CA) has advantages of environmental friendliness, low energy consumption, renewable and no secondary pollution. However, the high cost, poor stability and low reusability of free CA under harsh conditions limit its industrial applications. Great efforts have been devoted to developing CA mimetic nanozymes to solve these problems. In this work, ZIF-90-based nanoparticles were prepared to mimic the active center of natural CA. The excellent CA-like catalytic activity of ZIF-90 nanoparticles was confirmed by using hydrolysis of p-nitrophenyl acetate (p-NPA) as the model reaction. Moreover, modifying ZIF-90 with monoethanolamine (MEA) could further improve its affinity for CO 2 , which in turn enhances the CO 2 uptake capacity. Moreover, the hydrolysis of CO 2 was also investigated through the pH decrease of the reaction solution and the results indicated that CO 2 hydration and exchange were remarkably enhanced with the aid of ZIF-90 or ZIF-90 @MEA. This approach is facile and costless, which sheds light on the development of novel catalysts for industrial CO 2 capture. [Display omitted] [ABSTRACT FROM AUTHOR]

The goals of carbon neutrality and peak carbon have officially been proposed; consequently, carbon dioxide utilization and sequestration technology are now in the limelight. Injecting carbon dioxide into reservoirs and solidifying and sequestering it in the form of carbonates after a series of geochemical reactions not only reduces carbon emissions but also prevents carbon dioxide from leaking out of the formation. Carbon dioxide mineralization sequestration, which has good stability, has been considered the best choice for large-scale underground CO2 sequestration. To provide a comprehensive exploration of the research and prospective advancements in CO2 mineralization sequestration within Chinese oil and gas reservoirs, this paper undertakes a thorough review of the mechanisms involved in CO2 mineralization and sequestration. Special attention is given to the advancing front of carbon dioxide mineralization, which is driven by microbial metabolic activities and the presence of carbonic anhydrase within oil and gas reservoirs. The paper presents an in-depth analysis of the catalytic mechanisms, site locations, and structural attributes of carbonic anhydrase that are crucial to the mineralization processes of carbon dioxide. Particular emphasis is placed on delineating the pivotal role of this enzyme in the catalysis of carbon dioxide hydration and the promotion of carbonate mineralization and, ultimately, in the facilitation of efficient, stable sequestration. [ABSTRACT FROM AUTHOR]

CO2 sequestration in saline aquifers is one of the most potential sequestration modes, and saline aquifers are ideal sites for CO2 geological sequestration. After CO2 is injected into a saline aquifer, it will have a long-term complex geochemical reaction with the formation of minerals and water, and the minerals will undergo multiple reactions such as dissolution and reprecipitation. Therefore, an in-depth study of the geochemical reaction mechanisms between CO2 and formation minerals is of great significance to the accurate calculation and prediction of CO2 storage volume and the safety evaluation of long-term CO2 sequestration. In China, continental saline aquifers are widely distributed, whose mineral compositions and texture maturity are markedly different from those of the marine sedimentary basins in North America, and their stratigraphic environments are more complicated. The studies on the CO2–water–rock (mineral) still have many research gaps or insufficiencies, and there is no report on the dissolution mechanisms of individual minerals in the reaction. Taking one certain block of Daqing Oilfield, which is a typical continental deposit in China, as an example, we analyze the dissolution laws and four types of typical continental deposited minerals under the effect of CO2 and the change features of ionic compositions and pH of the formation water in the process of geochemical reaction. The research results indicate that CO2 has different dissolution degrees for the four types of minerals, among which, feldspar, as the main mineral in continental sedimentary formations, has the lowest dissolution rate. Furthermore, in terms of the water type (Na+-enriched NaHCO3) of the saline aquifer in the deep part of the continental deposit, feldspar can precipitate into the secondary minerals represented by dawsonite in the later stage, which can act as the potential minerals of carbon fixation to increase the CO2 mineralization storage volume in continental deposited saline aquifers. [ABSTRACT FROM AUTHOR]

Because of the growing demand for energy, oil extraction under complicated geological conditions is increasing. Herein, oil displacement by CO2 in wedge-shaped pores was investigated by molecular dynamics simulation. The results showed that, for both single and double wedge-shaped models, pore Ⅱ (pore size from 3 to 8 nm) exhibited a better CO2 flooding ability than pore Ⅰ (pore size from 8 to 3 nm). Compared with slit-shaped pores (3 and 8 nm), the overall oil displacement efficiency followed the sequence of 8 nm > double pore Ⅱ > single pore Ⅱ > 3 nm > double pore Ⅰ > single pore Ⅰ, which confirmed that the exits of the wedge-shaped pores had determinant effects on CO2 enhanced oil recovery over their entrances. "Oil/CO2 inter-pore migration" and "siphoning" phenomena occurred in wedge-shaped double pores by comparing the volumes of oil/CO2 and the center of mass. The results of the interaction and radial distribution function analyses indicate that the wide inlet and outlet had a larger CO2–oil contact surface, better phase miscibility, higher interaction, and faster displacement. These findings clarify the CO2 flooding mechanisms in wedge-shaped pores and provide a scientific basis for the practical applications of CO2 flooding. [ABSTRACT FROM AUTHOR]

Despite tremendous advancements in icephobic coating technology, icephobic efficacy frequently declines or completely disappears in low temperatures, high humidity, and dynamic environments. Here, a hyperbranched vanillin‐based composite coating with efficient icephobic properties (HVIC) is prepared by combining vanillin‐based phosphazene compounds with oil‐stored SiO2 through imine bonds‐ HVIC exhibits excellent hydrophobicity, with a water sliding angle of 9°. This coating's exceptional slippery performance imparts outstanding non‐adhesive, self‐cleaning characteristics, and deicing properties (τice: 8.2 kPa). It is noteworthy that HVIC performs exceptional anti‐icing and anti‐frosting in low‐temperature and high humidity environments. Compared with superhydrophobic coatings (SHC), the icing delay time of HVIC is 9.1 times that of SHC, and the frosting time is extended by roughly 300%. Most importantly, the HVIC‐treated propeller experienced two ice‐shedding events during the 200s dynamic icing test, while SHC completely lost its icephobic performance. This excellent dynamic icephobic performance can ensure the normal operation of the equipment while reducing energy consumption. The HVIC also exhibits significant UV shielding, antibacterial, flame retardant, self‐healing, and recyclability properties. The HVIC is regarded as having significant potential for application due to its easy and scalable approach. [ABSTRACT FROM AUTHOR]

Worldwide practices have proven that gas-assisted gravity drainage can obviously enhance oil recovery, and this technology can be especially effective for reservoirs with a thick formation and large inclination angle. For the successful implementation of this process, a key technology is the stable control of gas–oil interface during gas injection. For a detailed exploration of this technique, a three-stage permeable visual model was designed and manufactured, with permeability decreasing from top to bottom, thus, a reverse rhythm reservoir was effectively modeled. Then the experiment concerning CO2-assisted gravity drainage was carried out with the adoption of a self-developed micro visual displacement device. This study mainly focused on the micro migration law of gas–oil interface and the development effects of CO2-assisted gravity drainage. According to the experiments, CO2 fingering somewhat happens in the same permeable layer from the beginning of gas injection. However, phenomena of "wait" and "gas–oil interface self-adjustment" occur instead of flowing into the next layer when the injected CO2 reaches the boundary of the next lower permeability layer through the dominant channel. By the "gas–oil interface self-adjustment", the injected CO2 first enters into the pores of the relative higher permeability layer to the greatest extent, and thus expands the sweep volume. Futhermore, in the process of CO2 injection, obvious gas channeling occurs in the low permeability layer directly connected to the outlet, resulting in low sweep efficiency and poor development effect. After connecting the core with lower permeability at the outlet, the development indexes of the model, such as the producing degree of the low permeability layer, the oil recovery before and after gas breakthrough, are significantly improved, and the recovery degrees of the medium permeability layer and the high permeability layer are also improved, and the overall recovery factor is increased by 12.38%. This "gas–oil interface self-adjustment" phenomenon is explained reasonably from the two scales of macroscopic flow resistance and microscopic capillary force. Finally, the enlightenments of the new phenomenon are expounded on the application of gas-assisted gravity drainage on site and the treatment of producers with gas breakthrough in gas injection development. [ABSTRACT FROM AUTHOR]

Accurate black oil reservoir simulation is important for the understanding of underground resources in hydrology and petroleum reservoir engineering. The success of fast prediction relies on a robust and scalable black oil simulator, which can handle the complex subsurface fluid dynamics with coupling several different physical processes, and meanwhile run efficiently on distributed memory parallel computers. In this work, we introduce a highly parallel simulator to accurately compute the reservoir flow coupling with wells, including some adaptive fully implicit schemes for the temporal discretization, the improved active-set reduced-space algorithm for the nonlinear algebraic system, and several types of field-split methods for preconditioning. This parallel simulator is applied on the domain decomposition framework, which is designed to overcome the computational issues of traditional simulators implemented for personal computers or small workstations. High-resolution reservoir simulation results on the Society of Petroleum Engineers (SPE) comparative solution project or real-field cases are obtained and analyzed, and the parallel performance of the algorithm is studied on a supercomputer with scaling up to 27440 processor cores. The numerical experiments indicate that the proposed black oil simulator is capable of accurately predicting the highly complex physical processes and interactions between wells and the reservoir for full field scale simulation. • Adaptive time stepping scheme with finite volume method for fully implicit discretization. • An improved active-set reduced-space (ASRS) algorithm for bound-preserving solution. • Several types of field-split (FS) methods with domain decomposition for largescale preconditioning. • Complex black oil reservoir simulation with up to 27440 processor cores. [ABSTRACT FROM AUTHOR]

A pressure-driven breathing effect was discovered in x-pcu-n at 195 K. The dimensions were enlarged by 1.04–1.24 times at 20–40 kPa, from the small pore phase to the large pore phase. The CO 2 capture and separation performance were investigated in x-pcu-n. The CO 2 capture capacity reached 10.48 mmol/g in x-pcu-1 at 195 K and 100 kPa. [Display omitted] • Pressure-driven breathing effect was discovered in x-pcu-n at 195 K and 20–40 kPa. • Molecular dynamics (MD) and grand canonical Monte Carlo (GCMC) are employed to investigate the efficient CO 2 capture in x-pcu-n. • Structure with longer ligands (x-pcu-4) exhibits greater breathing effect, with the dimensions enlarged by 1.04–1.24 times after breathing effect. • X-pcu-4 demonstrates a CO 2 capture capacity of 10.48 mmol g−1 with a selectivity of 1714.44 for CO 2 over N 2. Developing efficient CO 2 adsorbents is imperative to mitigate excessive CO 2 emission. This study employs density functional theory (DFT), Molecular dynamics (MD) and grand canonical Monte Carlo (GCMC) simulations to investigate CO 2 capture performance in x-pcu-n via pressure-driven breathing effect at 195 K. The breathing effect is influenced by the ligand length and predominantly achieved through ligand twisting under 20–40 kPa. Longer ligands facilitate greater breathing effect, expanding dimensions by 1.04–1.24 times, thereby enhancing available space and exposing additional adsorption sites for selective CO 2 uptake. The resulting capacities are measured at 10.48, 9.44, 9.30, and 5.23mmol/g, with CO 2 over N 2 selectivity of 1714.44, 1368.84, 1784.15, and 1224.59, respectively, in x-pcu-n (n = 4, 3, 2, and 1) at 100 kPa. This study elucidates the pressure-driven breathing effect and their applicability in CO 2 capture and separation processes, offering theoretical insights for the development of efficient CO 2 adsorption materials utilizing pressure-driven flexible MOFs. [ABSTRACT FROM AUTHOR]

[Display omitted] • A vanillin-based icephobic coating with multiple dynamic bonds was prepared. • The anti-extreme-environment self-healing properties of the coating were achieved. • The coating possessed low ice adhesion strength and excellent anti-fouling properties. • The coatings exhibited good UV shielding performance and closed-loop recyclability. Outdoor icephobic coatings are prone to damage, particularly in extreme weather conditions like freezing temperatures and acid rain. Damage to the coating will result in a loss of icephobic function and may lead to increased icing. Furthermore, it is imperative to incorporate sustainability into icephobic coatings as environmental consciousness grows. Herein, a vanillin-based icephobic coating with anti-extreme-environment self-healing was prepared by incorporating vanillin-based polyols into prepolymers terminated with isocyanates that include silicone oil. The coating exhibited low ice adhesion with a measurement of 8.8 kPa, which was mainly attributed to the hydrophobicity of PDMS and the hydrophobic and lubricating characteristics of silicone oil. Moreover, the coating's remarkable chemical stability and ability to resist fouling were due to its lubricating and hydrophobic properties. More importantly, the coating retains impressive self-healing abilities in extreme conditions (−20 °C, pH = 1, pH = 14) due to the multiple dynamic bonds within the coating and the water-repelling and plasticizing effects of silicone oil. The coating maintained its original hydrophobic characteristics and low ice adhesion strength even after several recycling and self-healing cycles, demonstrating remarkable lifespan and sustainability. This work facilitates meeting the need for anti-icing in outdoor areas, particularly in extremely cold, acidic, and alkaline conditions. [ABSTRACT FROM AUTHOR]

Cross-borehole electrical resistivity tomography (CHERT) technology has been implemented in field-scale CCS/CCUS (carbon capture and storage/carbon capture, utilization and storage) projects. It is highly desirable to investigate how to optimize the design of the ERT electrode arrays and corresponding working schemes for both laboratory experiments and field applications. A CHERT system was developed for laboratory experiments of CO2 geological storage applications. An optimization method was established for optimizing the structure of electrode arrays and corresponding working schemes. The developed CHERT system was calibrated systematically to determine the measurement range and accuracy of electrical impedance. Laboratory experiments were designed and implemented to validate the performance of the developed CHERT system. It has been illustrated that: (1) It is an essential step to optimize the structure of electrode arrays and corresponding working schemes of CHERT according to the real application background. The optimization method based on finite-element modelling provides an effective means for designing a field-scale CHERT system. (2) The quality of the images inverted from the CHERT data is highly dependent on the working schemes and specific modes, which is closely related to the size of the data sets used for the inversion. The AM-BN scheme is recommended due to the better uniformity of the resultant sensitivity field and application to larger borehole spacing. (3) Based on the calibration, the measurement range of the developed CHERT system can be determined as 100 Ω to 4.5 kΩ with an error limit of 1.5%. The maximum relative errors of the impedance magnitude and phase angle are 5.0% and 7.0%, respectively. Based on the test results the location of the CO2-bearing objects can be identified accurately. The shapes of the tested objects present distortion to some extent, but this can be alleviated by selecting working modes with a larger size of data set. [ABSTRACT FROM AUTHOR]

Photothermal shape memory polyurethanes (SMPUs) have attracted more and more attention due to their precision, flexibility, and remote control. However, the current photothermal SMPUs often rely on petroleum-based resources and utilize inorganic or metal nanoparticles as photothermal agents, which would not only cause a resource crisis but also pollute the environment. In addition, their own non-recyclability would further expand the drawbacks mentioned above. Herein, we report nanoparticle-free, recyclable, and photothermal-responsive castor oil (CO)-based shape memory polyurethanes (denoted BPUs), which are synthesized by CO, 1,4-benzoquinone dioxime (BQDO), and 4,4′- methylenedicyclohexyl diisocyanate (HMDI). Benefits from the rational molecular design, the mechanical properties of BPUs can undergo a wide range of changes from soft to tough and then to hard. Compared with the control sample, the σ and E of BPUs are increased by 9.6–29.8 times and 3–854 times, respectively. They also showed exceptional malleability, reprocessability, recyclability, and dual-shape memory due to dynamic oxime-carbamate bonds formed by BQDO reacting with isocyanate. Specifically, after several thermal remodeling BPUs, their mechanical properties can basically return to more than 92% of the original sample. Moreover, BPUs can maintain R f and R r above 90% after several shape memory-reconstruction cycles. More importantly, BPUs have excellent photothermal performance due to the color and conjugate structure of BQDO. For example, BPU-2 can reach 102.1 °C after being exposed to NIR light with a power density of 0.8 W/cm2 for about 50 s. At the same time, several functional applications of BPUs have been developed based on the excellent photothermal performance of BQDO, such as photothermal shape memory, photothermal engines, and photothermal antibacterial (sterilization rate is around 99%). This work provides new enlightenment for the high-value utilization of CO-based SMPUs; and certain reference significance for the sustainable development of photothermal SMPUs. [Display omitted] • The nanoparticle-free and photothermal bio-based SMPUs were first synthesized. • The SMPUs have a wide range of tunable mechanical properties. • The SMPUs showed exceptional multiple recyclability, and dual-shape memory. • The SMPUs exhibited excellent photothermal performance and multiple applications. [ABSTRACT FROM AUTHOR]

Icephobic coatings have attracted wide attention due to low energy consumption, low cost, and high efficiency. However, the icephobic coating is vulnerable to external damage due to long-term exposure, which can result in icephobic properties loss and limit its industrial application. Herein, the novel amphiphilic epoxy self-healing icephobic coating was designed by a compound with multiple hydrophilic groups, polydimethylsiloxane (PDMS) with hydrophobic groups and 4, 4′-diaminodiphenyldisulfide (APD) with reversible bonds. Moreover, considering the resource crisis, the biobased epoxy (GTE) was selected as the compound containing hydrophilic groups. In this study, the GTE will form hydrogen bonds with water molecules to achieve an anti-icing effect, while PDMS mainly play a deicing effect due to low surface energy. Due to the reasonable design, the icephobic coating showed good comprehensive icephobic properties: a 12.5-fold increase in icing delay time (802 s) and a 6.6-fold decrease in ice adhesion strength (32.6 kPa) compared with bare aluminum. Furthermore, the crystallization temperature of water was reduced by about 11 °C. More importantly, the APD with reversible disulfide bonds provides the icephobic coating with self-healing performance, removability, and excellent UV shielding performance. The coating provides a new idea for the preparation of sustainable and durable coatings with comprehensive icephobic performance. [Display omitted] • The epoxy icephobic coatings were synthesized by simple one-pot method. • The GTE and PDMS endow the coating with comprehensive icephobic performance. • Self-healing properties and UV shielding are beneficial to prolong service life. • The biobased epoxy and removability are beneficial to the sustainability of the coating. [ABSTRACT FROM AUTHOR]

Geological CO 2 sequestration in deep saline aquifers has been extendedly investigated to reach the goal of carbon neutral as large amount of CO 2 can be reduced in a short time. This study investigates the feasibility of water-alternating-gas (WAG) injection and brine extraction on enhancing CO 2 storage in a target deep saline aquifer, Minnelusa Sandstone in the Powder River Basin (PRB) of Wyoming. An integrated numerical model is developed to account for four scenarios: (1) CO 2 continuous injection (CI) through one injection well, (2) WAG injection through one injection well, (3) CO 2 CI through one injection well and brine extraction through one producer, (4) WAG injection through one injection well and brine extraction through one producer. Simulation results suggest that WAG injection and brine extraction corporately make it possible to enhance CO 2 injectivity while securing CO 2 storage safety. For instance, WAG injection considerably reduces structural trapping contribution while enhances dissolved and residual trapping contributions. As for brine extraction, it can decrease the maximum averaged reservoir pressure by 37% and 22% for CI and WAG injection, respectively. Besides, sensitive analyses of the operational parameters for the fourth scenarios are performed. Results reveal that, when the amount of total CO 2 injection has been predetermined, CO 2 injection time and rate within each period of WAG should be small whereas it is preferable to have large water injection time and rate. This is to secure desirable dissolved and residual trapping contributions (store CO 2 with safety). Sensitive degree results confirm that CO 2 injection rate, water injection time, and CO 2 injection time of WAG injection exhibit significant effects on CO 2 storage whereas the impacts of producer bottom-hole pressure (BHP), water injection rate, and CO 2 -water injection time are relatively weaker. This study not only sheds light on achieving double-win goal: enhance CO 2 injectivity and store CO 2 with safety, but also can be a critical reference for other CO 2 storage in deep saline aquifers. • Geological model-based numerical simulations on CO2 injection into a real saline aquifer are performed. • Water-alternating-gas injection increases CO2 dissolved and residual trapping contributions. • Brine extraction through producer makes it possible to enhance CO2 injectivity. • Major parameters affecting CO2 trapping contribution and CO2 injectivity are screened. [ABSTRACT FROM AUTHOR]

Controlled fabrication of uniform graphene oxide (GO) films is of great demand for many applications such as biomedical and biosensing materials. Surface-supported GO films with different surface coverage and density have been successfully fabricated by Langmuir–Blodgett (LB) method. The dialyzed GO sheets with sizes of smaller than 200 nm are used for LB assembly so as to achieve well control over the quality of the GO films. The dialysis procedure can remove soluble impurities from the GO sheets to adjust the surface composition and physicochemical properties. GO sheets within nanometer sizes can avoid edge folding and stacking during LB assembly and get better control of interactions between GO sheets. These aspects help to fabricate the uniform LB assemblies of GO sheets successfully, which can then be transferred onto the solid surface to give GO films with controlled surface coverage and density. The surface-supported GO films show high stability and biocompatibility, which can mediate cell growth and proliferation. The study not only provides ways for controlling the physicochemical properties of the GO sheets but also depicts the controlled fabrication of uniform GO films for specific applications. [ABSTRACT FROM AUTHOR]

The development of high-performance CO2 capture and separation adsorbents is critical to alleviate the deteriorating environmental issues. Herein, N atom-doped layered graphene (N-MGN) was introduced to form triazine and pyridine as potential CO2 capture and separation adsorbents via regulation of interlayer spacings. Structural analyses showed that accessible surface area of the N-MGN is 2521.72 m2 g−1, the porosity increased from 9.43% to 84.86%. At ultra-low pressure, N-MGN_6.8 have exhibited a high CO2 adsorption capacity of 10.59 mmol/g at 298 K and 0.4 bar. At high pressure, the absolute adsorption capacities of CO2 in N-MGN_17.0 (40.16 mmol g−1) at 7.0 MPa and 298 K are much larger than that of N-doping slit pore. At 298 K and 1.0 bar, the highest selectivity of CO2 over N2 reached up to ~133 in N-MGN_6.8. The research shows that N doping can effectively improve the adsorption and separation capacity of CO2 and N2 in layered graphene, and the interlayer spacing has an important influence on the adsorption capacity of CO2/N2. The adsorption heat and relative concentration curves further confirmed that the layered graphene with an interlayer spacing of 6.8 Å has the best adsorption and separation ability of CO2 and N2 under low pressure. Under high pressure, the layered graphene with the interlayer spacing of 17.0 Å has the best adsorption and separation ability of CO2 and N2. [ABSTRACT FROM AUTHOR]

Carbonic anhydrase (CA) is an enzyme with unrivaled catalytic activity for CO 2 hydration reactions. However, its high cost and poor stability have severely limited its industrial application in CO 2 uptake. Constructing CA mimics is a promising strategy to overcome these limitations. In this work, a novel ZIF-8-based CA mimic, Cu@ZIF-8/Ag, was fabricated for CO 2 capture and storage. Esterase experiments confirmed that Cu@ZIF-8/Ag had higher CA-mimicking activity than ZIF-8 and Cu@ZIF-8, indicating that Cu-doping and in-situ growth of Ag nanoparticles significantly increased CA-like activity. Simulating the mineralization process in industrial applications, Cu@ZIF-8/Ag yielded the highest CaCO 3 yields. Additionally, Cu@ZIF-8/Ag has good reusability, with catalytic activity over 10 % higher than ZIF-8 even after seven adsorption and regeneration cycles. This activity-enhanced Cu@ZIF-8/Ag carbonic anhydrase mimic shows great potential for future CO 2 capture. [Display omitted] [ABSTRACT FROM AUTHOR]

• A compound system composed of Interfacially Active Polymer and Emulsifying Viscosity Reducer was proposed. • IAP-EVR compound system can form stable emulsion with low IAP and EVR concentrations. • The emulsifying viscosity reduction and emulsion stabilization of IAP-EVR compound system was evaluated. • Supramolecular network was formed by IAP-EVR compound system. • the oil displacement mechanism of IAP-EVR compound system were clarified. Chemical Cold Heavy Oil Production (CCHOP) represents an effective approach to exploit heavy oil by injecting Oil Viscosity Reducer (OVR). However, the challenge lies in the crossflow of traditional OVR through high permeability channels in heterogeneous heavy oil reservoirs. a supramolecular compound system comprising Interfacially Active Polymer (IAP) and Emulsifying Viscosity Reducer (EVR) were proposed as a novel CHHOP agent to address this problem. A series of experiments were conducted to investigate the heavy oil displacement performance and mechanism of the IAP-EVR compound system, including assessments of heavy oil emulsification, emulsion stability, rheological properties, single-core oil displacement, and heterogeneous microscopic oil displacement. The results demonstrate that a stable O/W emulsion can be formed with the 0.1 wt% IAP-0.3 wt% EVR compound system under a low mixing rate of 200 rpm. The emulsion exhibits only an 8.0% dewatering rate and a low TSI value of 0.8. Moreover, the compound system effectively reduces the heavy oil viscosity from 1000 mPa·s to 325.7 mPa·s, facilitating the emulsification of the remaining oil after water flooding and enhancing its flowability, thus improving oil displacement efficiency. Additionally, the 0.1 wt% IAP-0.3 wt% EVR compound system increases the solution viscosity to 600 mPa·s, leading to a low W/O mobility ratio, which enhances the swept volume. Supramolecular association is identified as a crucial mechanism for stabilizing the emulsion and increasing the solution viscosity, as evidenced by a high elastic modulus of 144.7 mPa and a transition area observed in the viscosity-shear rate curve. In comparison to HPAM and IAP, the 0.1 wt% IAP-0.3 wt% EVR compound system yields higher oil recoveries of 21.84 %OOIP in the single core experiment. Moreover, noticeable emulsification is observed in the produced fluid, and oil recoveries of 89.85 %OOIP and 92.98 %OOIP are achieved in high and low permeable areas, respectively, in the heterogeneous microscopic model. These results indicate a mechanism that enhances both the swept volume and oil displacement efficiency. Overall, the findings of this study provide a laboratory foundation for the promising application of the IAP-EVR compound system in heterogeneous heavy oil reservoirs. [ABSTRACT FROM AUTHOR]

[Display omitted] • The idea of storage and replacement of CO 2 -rich IWG in shale gas reservoir was proposed and verified. • The adsorption rules of CO 2 -rich IWG on shale minerals was achieved and applied to perform MDS. • The adsorption capacity and microscopic mechanisms of different components on shale were discovered. • The competitive adsorption characteristics and mechanisms of different components with CH 4 on shale were revealed. Clean utilization of CO 2 -rich industrial waste gas (CO 2 -rich IWG) is of great significance to realize carbon neutralization. Due to the strong adsorption capacity of clay and organic matter in shale to CO 2 , it has a good potential for CO 2 -rich IWG storage and replacement. So, the feasibility of using CO 2 -rich IWG replacement for shale gas exploration from the perspective of adsorption was studied. A shale composite model was constructed based on the adsorption experiments, and the molecular simulation results were fitted with experiments for the model reliability. Then, the slit models of different minerals were constructed to study the adsorption mechanisms. Finally, the competitive adsorption mechanisms of different components with CH 4 were revealed. The results show that the overall adsorption capacity on shale minerals are ranked as HF > CO 2 > SO 2 > H 2 S > NO 2 > CH 4 > CO；Hydrogen bond and electrostatic force are the main adsorption modes of HF, and electrostatic force between negatively charged atoms of gas molecule and mineral surface is the main adsorption modes of CO 2 , SO 2 and H 2 S. That of NO 2 , CH 4 and CO is the weak van der Waals force. In the competition with CH 4 , the absolute adsorption capacity of gas decreases, but the relative adsorption capacity increases. The relative adsorption capacities of HF, CO 2 , H 2 S and SO 2 increase by 35, 26, 15 and 12 times, respectively. During competitive adsorption, negatively charged atoms in HF, CO 2 , H 2 S and SO 2 are more likely to bind with free cations on the surface of illite and smectite, and generate electrostatic repulsion for C atoms in CH 4 , leading to the weakening or even disappearance of CH 4 adsorption capacity. [ABSTRACT FROM AUTHOR]

[Display omitted] • The ignition temperature of BDMS/hybrid fuel 10 decreased drastically to 213 °C. • PAH formation was reduced by 87% compared to hybrid fuel 10 without BDMS. • BDMS improve the evaporation and low-temperature oxidation of hybrid fuel 10. • BDMS promotes the graphitization of soot during hybrid fuel 10 combustion. Soot is carbonaceous particulate produced by incomplete combustion of hydrocarbon fuel, reducing the efficiency of energy utilization and affecting the environment and people's health adversely. Naphthenic hydrocarbons are essential components in diesel and kerosene, generating great quantities polycyclic aromatic hydrocarbons (PAHs) and subsequently soot particles in the combustion process at high temperature. In this study, a new strategy of cycloalkane combustion at low temperature is developed to reduce the formation of the PAH soot-precursors in the combustion process to decrease soot emission. Borane-dimethyl sulfide (BDMS) and n- hexadecane were employed to promote the low-temperature ignition of cycloalkanes and the reduction of soot emission. By adding of 5% BDMS, the ignition temperature of hybrid fuel 10 (10 vol% n- hexadecane, 90 vol% cyclohexane) decreased drastically from 570 °C to 213 °C and PAH formation was reduced by 87%. In the flame development stage of the combustion process, the flame of BDMS/hybrid fuel 10 appears green in color and is larger than the blue flame in the stage of flame reduction, indicating the complete combustion of cycloalkane fuels. By this strategy of low-temperature combustion, the generation of PAH during combustion of cyclohexane decreases, thereby reducing the generation of soot and improving hydrocarbon fuels utilization. [ABSTRACT FROM AUTHOR]