Sodium metal batteries (SMBs) are regarded as highly promising candidates for next?generation high?energy?density energy storage systems, owing to the high theoretical specific capacity (1 166 mA?h/g) and low redox potential (-2.71 V（vs.SHE）) of sodium metal. However, the practical implementation of sodium metal anodes is significantly impeded by several critical issues, including uncontrollable dendrite growth, vigorous interfacial side reactions, and instability of the solid electrolyte interphase (SEI). Consequently, engineering a stable and robust anode interface has become a pivotal research focus for achieving high?performance SMBs. In recent years, researchers have proposed a variety of interfacial regulation strategies, including electrolyte optimization, artificial interfacial layer construction, application of solid?state or gel electrolytes, and alloying approaches. This review systematically summarizes recent progress in stabilizing the sodium metal anode interface, with a focus on the mechanismsof various interface engineering strategies and their effects on electrochemical performance. The challenges and future perspectives in this field are also discussed.
This study investigates the effect of preparation strategies on the state of active species in Beta zeolite supported P and Ni catalysts,to develop high?performance catalysts for the selective hydrogenation of furfural.A series of P?modified Beta zeolite supported Ni catalysts were prepared by stepwise introduction of Ni and P through different methods.Various characterization techniques were employed to investigate the state of Ni species,and their catalytic performance in the selective hydrogenation of furfural was evaluated.The results revealed that Ni species introduced via the in?situ hydrothermal method were uniformly encapsulated within the zeolite channels.P introduced via mechanical mixing migrated into the channels and interacted with Ni to form Ni2P species during reduction treatment.The high content of Ni2+ in P?Ni@Beta indicated a strong metal?support interaction.The reaction results demonstrated a blue shift in the C-O stretching frequency,indicating electron transfer from Ni to P,which reduced the electron density around Ni.The reaction results indicated that Ni δ+ species,acting as Lewis acid sites,efficiently promoted the selective hydrogenation of furfural.Under conditions of 110 ℃ and 1 MPa H2,a furfuryl alcohol yield of 68.6% was achieved after 1 h of reaction.
An oil?soluble molybdenum sulfide catalyst (MS?1) was prepared by a ‘one?pot’ synthesis method and characterized using XRD,FT?IR,XPS,and HR?TEM.The hydrodeoxygenation (HDO) performance toward methyl oleate and the hydrotreating capability for waste oils (with phosphorus,chlorine,and total metal contents of 18.14,138.80,and 173.60 μg/g,respectively) were evaluated in a high?pressure reactor.The results indicate that two?dimensional monolayer MoS2 active species were generated in situ during reaction,and the synthesized catalyst exhibited excellent overall performance.Under the conditions of a catalyst dosage of 380 μg/g,a reaction temperature of 360 °C,an initial H2 pressure of 4.0 MPa,and a reaction time of 3.0 h,the deoxygenation rates of methyl oleate and waste cooking oil reached 99.2% and 99.7%,respectively.The acid value and bromine value of the waste oil were significantly reduced from 173.60 mgKOH/g and 117.70 gBr/(100 g) to 5.28 mgKOH/g and 5.65 gBr/(100 g).The removal efficiencies of phosphorus,chlorine, and total metals were 92.17%,93.87%,and 96.92%,respectively.
Microscopic pore throat structure is the key focus and challenge of tight sandstone reservoir research.Regarding the Chang 6 tight sandstone in the Jiyuan area of the Ordos Basin,casting thin sections,scanning electron microscopy,and constant rate mercury injection experiments were used,and fractal theory was introduced to study its pore throat characteristics.The study shows that the pore throat of tight sandstone can be divided into two types:large?scale and small?scale.The large?scale pore throats are mainly dissolution pores,composite pores and curved lamellar throats.The pore throat has large storage space,obvious pore throat deformation,strong heterogeneity and large fractal dimension.The small?scale pore throats are strongly compacted and cemented, and mainly consist of intergranular pores,intercrystalline pores and necked throats with little deformation of pore?throat space,weak heterogeneity and small fractal dimension.There is a good positive correlation between the fractal dimension and the effective reservoir space.The better the reservoir is,the stronger the heterogeneity will be,and the larger the fractal dimension will be.There is also a good correlation between the fractal dimension and the pore throat structure parameter.The pore throat distribution is uneven,the connectivity is poor,the larger the fractal dimension will be.The mass fraction of clay minerals is an important factor affecting the fractal dimension of pore throat,which in turn reflects the quality and pore throat characteristics of reservoirs.
Aiming at the problems of conventional temporary plugging materials in horizontal shale gas wells in Sichuan, such as insignificant increase in temporary plugging pressure, easy shedding under low pressure difference and poor plugging effect, long?acting and short?acting temporary plugging knots for perforation plugging were prepared. Their degradation performance and pressure?bearing plugging performance were evaluated, the influence of injection method on plugging efficiency was explored, and a temporary plugging knot injection device was developed, thus forming a knot?based temporary plugging fracturing technology for shale gas. The results show that in polymer slick?water fracturing fluid at 90 ℃, the degradation rate of long?acting temporary plugging knots is less than 10% within 83 h and more than 99% after 174 h, while that of short?acting temporary plugging knots is less than 10% within 5 h and more than 99% after 24 h. Both types of temporary plugging knots exhibit static pressure?bearing capacity higher than 50.0 MPa and dynamic plugging efficiency above 90%. The maximum single injection capacity of the device is 60 temporary plugging knots with a size of 18~20 mm, and the injection rate is adjustable from 1 to 60 knots per minute. Field tests were carried out in Well Ning?A, a horizontal shale gas well, including 5 stages of inter?stage temporary plugging and 6 stages of intra?stage temporary plugging in casing?deformed intervals. The average post?plugging pressure increases were 9.0 MPa and 5.6 MPa, respectively. Field microseismic monitoring shows obvious differences in event points before and after temporary plugging, verifying the effectiveness of the proposed technology.
Microbiologically corrosion is a critical factor contributing to the degradation of marine engineering infrastructure.Electrochemical methods and slow strain rate tensile(SSRT) tests were employed to evaluate the effect of cathodic protection (CP) on the corrosion behavior of X70 pipeline steel in marine environments containing sulfate?reducing bacteria (SRB).Together with microstructural characterization,the stress corrosion cracking(SCC) mechanism of X70 steel in SRB?containing marine environments was analyzed.The results indicate that CP potentials of -0.775,-0.850 V promoted SRB growth.When the CP potential reached -1.000 V,it not only promoted the proliferation of SRB but also accelerated their transition into the decline phase.In the absence of applied stress,the optimal CP potential for X70 steel in SRB?containing marine environments was -0.850 V.Without CP,the SCC mechanism of X70 steel was a hybrid mode involving anodic dissolution induced by the marine environment and hydrogen?induced cracking caused by SRB.At CP potentials of -0.775,-0.850 V,the SCC mechanism was dominated by SRB?induced hydrogen?induced cracking.When the CP potential was -1.000 V,the SCC mechanism was a hybrid mechanism jointly induced by anodic dissolution caused by the marine environment and hydrogen?induced cracking induced by the CP potential.The synergistic effect of SRB and CP significantly increased the hydrogen embrittlement susceptibility of X70 steel in marine environments.
In view of the characteristics of high salinity of injected water,high reservoir temperature and multiple reservoir layers in Block G of Dagang K Oilfield,experiments were conducted to screen temperature?resistant and salt?tolerant polymers and surfactants.On this basis,the oil displacement efficiency of polymer solutions and polymer?surfactant binary composite flooding systems(hereinafter referred to as polymer/surfactant binary flooding systems) was investigated using multi‐layer core models.The results show that among the three types of polymers,hydrophobically associating polymers exhibit superior viscosity enhancement. Compared with HSY and DWS,the polymer/surfactant binary flooding system formulated with DG‐1 surfactant can reduce the interfacial tension to 10?3 mN/m.Under the same model layer combination,the incremental oil recovery of the polymer/surfactant binary flooding system is higher than that of the polymer solution;in particular,the incremental oil recovery of the binary flooding system is 1.43% higher in the three‐layer model with a permeability ratio of 10. Under the same flooding agent condition,the mass fraction and viscosity of polymer and surfactant in the produced fluid increase with the increase of model permeability ratio.At the same permeability ratio,a larger number of model layers leads to higher waterflooding recovery,lower chemical flooding and subsequent waterflooding recovery,while the ultimate oil recovery is similar.
In view of the characteristics of high porosity and high permeability in heavy oil reservoirs,together with the high?intensity injection?production conditions,challenges such as thermal fluid channeling,sudden increase in water cut,and deteriorating development performance have become increasingly prominent in the middle and late stages of steam flooding.Therefore,new technologies are urgently needed to further enhance development efficiency.The variation laws of thermal fluid temperature field and saturation field were investigated via numerical simulation and laboratory simulation experiments,on the basis of which the thermochemical?gas alternating flooding technology was studied.The results show that in the middle and late stages of the conversion from cyclic steam stimulation to steam flooding in thin heavy oil reservoirs,thermal communication occurs in some wells within the well group;the expansion radius of the temperature field reaches 100~140 m,and the water cut rises to 74%. According to the analysis of the heating chamber expansion law,the area ratio of the heated zone to the unheated zone in the reservoir is close to 1∶1,and the remaining oil in the unheated zone is abundant but not effectively produced.By optimizing the composite system composed of high?temperature reinforced foam and high?temperature?resistant low?viscosity consolidated gel, the plugging efficiency can exceed 97.0%,realizing fluid diversion and enabling the recovery of enriched remaining oil.A process is proposed that utilizes the residual heat in the formation supplemented by hot water,combined with alternate injection of flue gas and other gases.Numerical simulation results indicate that the oil recovery factor can be improved by approximately 2.00%.
Carbon dioxide (CO2) foam fracturing fluid features the advantages of low water consumption, weak reservoir damage, and excellent stimulation performance, making it particularly suitable for the extraction of water?sensitive unconventional shale oil and gas as well as coalbed methane. To address the poor stability of traditional CO2 foam fracturing fluids, flake?structured nano?graphene oxide (GO) was used to modify the CO2 foam fracturing fluid. The CO2 foam fracturing fluid was prepared in a sealed reactor, and the variation of foam half?life with surfactant type was investigated by visual observation to optimize the formulas. Subsequently, the effects of surfactant type, concentration, and temperature on the stability of the CO2 foam fracturing fluid were studied. The results show that the addition of GO to the octadecyltrimethylammonium chloride (OTAC) system leads to a large amount of flocculent material and fails to stabilize the foam. In contrast, the α?olefin sulfonate (AOS) system exhibits good compatibility with GO. The formula of 0.50%AOS+1.00%NaCl+0.25%GO presents high foam quality, and the introduction of GO significantly improves the temperature resistance of the foam system. A foam liquid film model was constructed using Materials Studio, and molecular dynamics simulations were performed to reveal the synergistic foam?stabilizing mechanism and failure mechanism of GO at the molecular level. This study provides a theoretical basis and technical support for the development of oil and gas reservoirs.
