An effective parameter in the miscible-CO_2 enhanced oil recovery procedure is the minimum miscibility pressure(MMP)defined as the lowest pressure that the oil in place and the injected gas into reservoir achieve misc...An effective parameter in the miscible-CO_2 enhanced oil recovery procedure is the minimum miscibility pressure(MMP)defined as the lowest pressure that the oil in place and the injected gas into reservoir achieve miscibility at a given temperature. Flue gases released from power plants can provide an available source of CO_2,which would otherwise be emitted to the atmosphere, for injection into a reservoir. However, the costs related to gas extraction from flue gases is potentially high. Hence, greater understanding the role of impurities in miscibility characteristics between CO_2 and reservoir fluids helps to establish which impurities are tolerable and which are not. In this study, we simulate the effects of the impurities nitrogen(N_2), methane(C_1), ethane(C_2) and propane(C_3) on CO_2 MMP. The simulation results reveal that,as an impurity, nitrogen increases CO_2–oil MMP more so than methane. On the other hand, increasing the propane(C_3)content can lead to a significant decrease in CO_2 MMP, whereas varying the concentrations of ethane(C_2) does not have a significant effect on the minimum miscibility pressure of reservoir crude oil and CO_2 gas. The novel relationships established are particularly valuable in circumstances where MMP experimental data are not available.展开更多
The diffusion coefficient of natural gas in foamy oil is one of the key parameters to evaluate the feasibility of gas injection for enhanced oil recovery in foamy oil reservoirs. In this paper, a PVT cell was used to ...The diffusion coefficient of natural gas in foamy oil is one of the key parameters to evaluate the feasibility of gas injection for enhanced oil recovery in foamy oil reservoirs. In this paper, a PVT cell was used to measure diffusion coefficients of natural gas in Venezuela foamy oil at high pressures, and a new method for deter- mining the diffusion coefficient in the foamy oil was de- veloped on the basis of experimental data. The effects of pressure and the types of the liquid phase on the diffusion coefficient of the natural gas were discussed. The results indicate that the diffusion coefficients of natural gas in foamy oil, saturated oil, and dead oil increase linearly with increasing pressure. The diffusion coefficient of natural gas in the foamy oil at 20 MPa was 2.93 times larger than that at 8.65 MPa. The diffusion coefficient of the natural gas in dead oil was 3.02 and 4.02 times than that of the natural gas in saturated oil and foamy oil when the pressure was 20 MPa. However, the gas content of foamy oil was 16.9 times higher than that of dead oil when the dissolution time and pressure were 20 MPa and 35.22 h, respectively.展开更多
An accurate and reliable estimation of minimum miscibility pressure(MMP) of CO2-oil system is a critical task for the design and implementation of CO2 miscible displacement process.In this study,an improved CO2-oil MM...An accurate and reliable estimation of minimum miscibility pressure(MMP) of CO2-oil system is a critical task for the design and implementation of CO2 miscible displacement process.In this study,an improved CO2-oil MMP correlation was developed to predict the MMP values for both pure and impure CO2 injection cases based on ten influential factors,i.e.reservoir temperature(TR),molecular weight of C7+oil components(MWC7+),mole fraction of volatile oil components(xvol),mole fraction of C2-C4 oil components(xC2-C4),mole fraction of C5-C6 oil components(xCs-5-C6),and the gas stream mole fractions of CO2(yCO2),H2S(yH2S),C1(yC1),hydrocarbons(yHC)and N2(yN2).The accuracy of the improved correlation was evaluated against experimental data reported in literature concurrently with those estimated by several renowned correlations.It was found that the improved correlation provided higher prediction accuracy and consistency with literature experimental data than other literature correlations.In addition,the predictive capability of the improved correlation was further validated by predicting an experimentally measured CO2-Oil MMP data,and it showed an accurate result with the absolute deviation of 4.15%.Besides,the differential analysis of the improved correlation was analyzed to estimate the impact of parameters uncertainty in the original MMP data on the calculated results.Also,sensitivity analysis was performed to analyze the influence of each parameter on MMP qualitatively and quantitatively.The results revealed that the increase of xC2-C4,xC5-C6 and yH2 S lead to the decrease of MMP,while the increase of TR,MWC7+,xvol,yCO2,YC1,yHC and yN2 tend to increase the MMP.Overall,the relevance of each parameter with MMP follows the order of TR> xC5-C6> MWC7+> xvol> yH2 S> yHC> yCO2>yC1>yN2>xC2-C4.展开更多
In deep oil reservoir development,enhanced oil recovery(EOR)techniques encounter significant challenges under high-temperature and high-salinity conditions.Traditional profile-control agents often fail to maintain sta...In deep oil reservoir development,enhanced oil recovery(EOR)techniques encounter significant challenges under high-temperature and high-salinity conditions.Traditional profile-control agents often fail to maintain stable blocking under extreme conditions and exhibit poor resistance to high temperature and high salinity.This study develops a functionalized nanographite system(the MEGO system)with superior high-temperature dispersibility and thermosalinity-responsive capability through polyether amine(PEA)grafting and noncovalent interactions with disodium naphthalene sulfonate(DNS)molecules.The grafted PEA and DNS provide steric hindrance and electrostatic repulsion,enhancing thermal and salinity resistance.After ten days of aggregation,the MEGO system forms stable particle aggregates(55.51-61.80 lm)that are suitable for deep reservoir migration and profile control.Both experiments and simulations reveal that particle size variations are synergistically controlled by temperature and salt ions(Na^(+),Ca^(2+),and Mg^(2+)).Compared with monovalent ions,divalent ions promote nanographite aggregation more strongly through double-layer compression and bridging effects.In core displacement experiments,the MEGO system demonstrated superior performance in reservoirs with permeabilities ranging from 21.6 to 103 mD.The aggregates formed within the pore throats significantly enhanced flow resistance,expanded the sweep volume,and increased the overall oil recovery to 56.01%.This research indicates that the MEGO system holds excellent potential for EOR in deep oil reservoirs.展开更多
Semen Platycladi(SP)is the dried ripe kernel of Platycladus orientalis(L.)Franco,has been used for insomnia treatment for bimillennium in China,which mechanism is not fully understood.The aim of this study was to expl...Semen Platycladi(SP)is the dried ripe kernel of Platycladus orientalis(L.)Franco,has been used for insomnia treatment for bimillennium in China,which mechanism is not fully understood.The aim of this study was to explore the sleep-promoting mechanism of essential oil and saponins from SP.As 2 main bioactive constituents of SP,essential oil(SPO)and saponin(SPS)were extracted,then was given to p-chlorophenylalanine(PCPA)-induced insomnia mice by intragastric administration.Then,the behavioral tests,neurotransmitter receptors,cytokines and hormone in brain were investigated.Behavior test showed that SPO and SPS exhibited sleep-enhancing effect through suppressing depression,shortening the onset time while prolonging the sleep duration in insomnia mice.Also SPO and SPS up-regulated serotonin(5-HT)receptors in serotonergic neurons,increased glutamic acid decarboxylase(GAD)content in GABAergic neurons,and stimulatedγ-aminobutyric acid(GABA)receptors expression to enhance the synaptic inhibition.Moreover,they could down-regulated the cytokines and rebalanced hormone expressions.Although both SPO and SPS exerted sleep-promoting,they had different focusing targets.SPS had stronger effect on neurotransmitter receptors regulation while SPO had better hormone rebalanced ability.Briefly,SPO and SPS exerted sedative-hypnotic effect in insomnia mice through modulating multi-targets in serotonergic and GABAergic system.展开更多
Data center cooling systems are substantial energy consumers,and managing the heat generated by electronic devices is becoming more complex as chip power levels continue to rise.The single-phase immersion cooling(SPIC...Data center cooling systems are substantial energy consumers,and managing the heat generated by electronic devices is becoming more complex as chip power levels continue to rise.The single-phase immersion cooling(SPIC)server with oil coolant is numerically investigated using the validated Re-Normalization Group(RNG)k-εmodel.For the investigated scenarios where coolant velocity at the tank inlet is 0.004 m/s and the total power is 740 W,the heat transfer between the heat sinks and the coolant is dominated by natural convection,although forced convection mediates the overall heat transfer inside the tank.The maximum velocity of coolant through the heat sink is 0.035 m/s and the average heat transfer coefficient is up to 75.8 W/(m2·K).The geometry of the heat sink is important for the cooling performance.Increasing both the fin thickness and number enhances the natural convection effect of the heat sink,but also increases the flow resistance.The heat sink with a fin thickness of 3 mm performs the best,reducing the average graphics processing unit(GPU)temperature from 71.3℃ to 68.6℃.A heat sink with an optimal fin number of 16 reduces the average GPU temperature to 67.7℃.As for the effect of fin height,increasing it from 15 to 30 mm results in increases in the heat transfer area and flow rate by about 72%and 32%,respectively,which reduces the average GPU temperature to 65.2℃.Therefore,the importance of fin parameters ranks in the following order:fin height,number,and thickness.This study highlights the potential application of oil coolants in SPIC systems and offers theoretical guidance for the efficient design of natural convection cooling solutions.展开更多
BACKGROUND Silicone oil(SiO)migration to the central nervous system(CNS)is a rare complication of SiO tamponade after vitreo-retinal surgeries,it could masquerade hemorrhage on computed tomography neuro-imaging.Only l...BACKGROUND Silicone oil(SiO)migration to the central nervous system(CNS)is a rare complication of SiO tamponade after vitreo-retinal surgeries,it could masquerade hemorrhage on computed tomography neuro-imaging.Only limited cases were reported in the literature,certain intra-operative and post-operative ocular risk factors might contribute to the different extend of SiO migration in the CNS.AIM To study the risk factors for cerebral ventricular migration(CVM)on top of visual pathway migration(VPM).METHODS Conforming to the preferred reporting items for systematic reviews and metaanalyses guidelines,literature searches on PubMed,MEDLINE,EMBASE were performed on June 1,2024.Publications on SiO migration to CNS were included in this review.Non-English articles,and studies without neuro-imaging of the CNS were excluded.Patient demographics,SiO filled eyes'ocular characteristics and vitrectomy surgical details were extracted from included studies in this review.VPM and CVM were assigned as group 1 and group 2 respectively.Fisher's exact tests,Mann-Whitney U tests and binary logistic regression were performed.RESULTS Total 68 articles were obtained after searches,48 publications were included for analysis.Total 54 SiO filled eyes were analyzed.Post-vitrectomy intraocular pressure(IOP)was found to be significant in both Mann-Whitney U test(P=0.047)and binary logistic regression(P=0.012).Diabetic was found to be significant in binary logistic regression(P=0.037),but at borderline risk for CVM in Fisher's exact test(P=0.05).Other significant factors include longer SiO tamponade time(P=0.002 in Fisher's exact test)and visual acuity(P=0.011 in binary logistic regression).Optic nerve atrophy or disc cupping(P=1.00,P=0.790)and congenital optic disc anomalies(P=0.424)were all with P>0.05.CONCLUSION SiO migration to CNS is rare with limited case reports only.Our analysis of the existing literature demonstrated higher post-vitrectomy IOP was associated with CVM,followed by patients’diabetic status,longer SiO tamponade time and visual acuity.Optic nerve atrophy,disc cupping and congenital optic disc anomalies were not associated.Modifiable risk factors of post-vitrectomy IOP and SiO tamponade time should be closely monitored by vitreoretinal surgeons.Lower IOP target post-vitrectomy and earlier SiO removal surgeries should be arranged.展开更多
The importance of organic geochemistry and basin modeling is widely recognized and used to understand the source rock potential and hydrocarbon generation history of the Mangahewa Formation,and thereby given the found...The importance of organic geochemistry and basin modeling is widely recognized and used to understand the source rock potential and hydrocarbon generation history of the Mangahewa Formation,and thereby given the foundational role in the petroleum exploration.This study utilized the total organic carbon(TOC)content and hydrogen index(HI)to investigate the dominant kerogen type and hydrogen richness for the significance of petroleum generative potential.The Mangahewa coals and carbonaceous shales exhibit an excellent source rocks,with high total organic content(TOC)of more than 22%.The coals and carbonaceous shales were also characterised by Type Ⅱ‒Ⅲ kerogen with Type Ⅲ kerogen,promising oiland gas-prones.The Mangahewa Formation reached the main oil generation,with vitrinite reflectances between 0.53%and 1.01%.Vitrinite reflectance was also used in developing themal models and reveal the transformation(TR)of 10‒50%kerogen to oil during the Late Miocene.The models also showed that the Mangahewa source rock has a significant oil generation and little expulsion competency,with a TR of up to 54%.These findings support the substantial oil-generating potential in the Taranaki Basin's southern graben and can be used as a guide when developing strategies for an oil exploration program.展开更多
By investigating the performance characteristics of the bio-based surfactant 8901A,a composite decontamination and injection system was developed using 8901A as the primary agent,tailored for application in low-permea...By investigating the performance characteristics of the bio-based surfactant 8901A,a composite decontamination and injection system was developed using 8901A as the primary agent,tailored for application in low-permeability and heavy oil reservoirs under varying temperature conditions.The results demonstrate that this system effectively reduces oil–water interfacial tension,achieving an ultra-low interfacial tension state.The static oil washing efficiency of oil sands exceeds 85%,the average pressure reduction rate reaches 21.55%,and the oil recovery rate improves by 13.54%.These enhancements significantly increase the system’s ability to dissolve oilbased blockages,thereby lowering water injection pressure caused by organic fouling,increasing the injection volume of injection wells,and ultimately improving oil recovery efficiency.展开更多
Path planning for recovery is studied on the engineering background of double unmanned surface vehicles(USVs)towing oil booms for oil spill recovery.Given the influence of obstacles on the sea,the improved artificial ...Path planning for recovery is studied on the engineering background of double unmanned surface vehicles(USVs)towing oil booms for oil spill recovery.Given the influence of obstacles on the sea,the improved artificial potential field(APF)method is used for path planning.For addressing the two problems of unreachable target and local minimum in the APF,three improved algorithms are proposed by combining the motion performance constraints of the double USV system.These algorithms are then combined as the final APF-123 algorithm for oil spill recovery.Multiple sets of simulation tests are designed according to the flaws of the APF and the process of oil spill recovery.Results show that the proposed algorithms can ensure the system’s safety in tracking oil spills in a complex environment,and the speed is increased by more than 40%compared with the APF method.展开更多
The hybrid CO_(2) thermal technique has achieved considerable success globally in extracting residual heavy oil from reserves following a long-term steam stimulation process.Using microscopic visualization experiments...The hybrid CO_(2) thermal technique has achieved considerable success globally in extracting residual heavy oil from reserves following a long-term steam stimulation process.Using microscopic visualization experiments and molecular dynamics(MD)simulations,this study investigates the microscopic enhanced oil recovery(EOR)mechanisms underlying residual oil removal using hybrid CO_(2) thermal systems.Based on the experimental models for the occurrence of heavy oil,this study evaluates the performance of hybrid CO_(2) thermal systems under various conditions using MD simulations.The results demonstrate that introducing CO_(2) molecules into heavy oil can effectively penetrate and decompose dense aggregates that are originally formed on hydrophobic surfaces.A stable miscible hybrid CO_(2) thermal system,with a high effective distribution ratio of CO_(2),proficiently reduces the interaction energies between heavy oil and rock surfaces,as well as within heavy oil.A visualization analysis of the interactions reveals that strong van der Waals(vdW)attractions occur between CO_(2) and heavy oil molecules,effectively promoting the decomposition and swelling of heavy oil.This unlocks the residual oil on the hydrophobic surfaces.Considering the impacts of temperature and CO_(2) concentration,an optimal gas-to-steam injection ratio(here,the CO_(2):steam ratio)ranging between 1:6 and 1:9 is recommended.This study examines the microscopic mechanisms underlying the hybrid CO_(2) thermal technique at a molecular scale,providing a significant theoretical guide for its expanded application in EOR.展开更多
Emulsification is one of the important mechanisms of surfactant flooding. To improve oil recovery for low permeability reservoirs, a highly efficient emulsification oil flooding system consisting of anionic surfactant...Emulsification is one of the important mechanisms of surfactant flooding. To improve oil recovery for low permeability reservoirs, a highly efficient emulsification oil flooding system consisting of anionic surfactant sodium alkyl glucosyl hydroxypropyl sulfonate(APGSHS) and zwitterionic surfactant octadecyl betaine(BS-18) is proposed. The performance of APGSHS/BS-18 mixed surfactant system was evaluated in terms of interfacial tension, emulsification capability, emulsion size and distribution, wettability alteration, temperature-resistance and salt-resistance. The emulsification speed was used to evaluate the emulsification ability of surfactant systems, and the results show that mixed surfactant systems can completely emulsify the crude oil into emulsions droplets even under low energy conditions. Meanwhile,the system exhibits good temperature and salt resistance. Finally, the best oil recovery of 25.45% is achieved for low permeability core by the mixed surfactant system with a total concentration of 0.3 wt%while the molar ratio of APGSHS:BS-18 is 4:6. The current study indicates that the anionic/zwitterionic mixed surfactant system can improve the oil flooding efficiency and is potential candidate for application in low permeability reservoirs.展开更多
In-situ upgrading by heating is feasible for low-maturity shale oil,where the pore space dynamically evolves.We characterize this response for a heated substrate concurrently imaged by SEM.We systematically follow the...In-situ upgrading by heating is feasible for low-maturity shale oil,where the pore space dynamically evolves.We characterize this response for a heated substrate concurrently imaged by SEM.We systematically follow the evolution of pore quantity,size(length,width and cross-sectional area),orientation,shape(aspect ratio,roundness and solidity)and their anisotropy—interpreted by machine learning.Results indicate that heating generates new pores in both organic matter and inorganic minerals.However,the newly formed pores are smaller than the original pores and thus reduce average lengths and widths of the bedding-parallel pore system.Conversely,the average pore lengths and widths are increased in the bedding-perpendicular direction.Besides,heating increases the cross-sectional area of pores in low-maturity oil shales,where this growth tendency fluctuates at<300℃ but becomes steady at>300℃.In addition,the orientation and shape of the newly-formed heating-induced pores follow the habit of the original pores and follow the initial probability distributions of pore orientation and shape.Herein,limited anisotropy is detected in pore direction and shape,indicating similar modes of evolution both bedding-parallel and bedding-normal.We propose a straightforward but robust model to describe evolution of pore system in low-maturity oil shales during heating.展开更多
According to the complex differential accumulation history of deep marine oil and gas in superimposed basins,the Lower Paleozoic petroleum system in Tahe Oilfield of Tarim Basin is selected as a typical case,and the p...According to the complex differential accumulation history of deep marine oil and gas in superimposed basins,the Lower Paleozoic petroleum system in Tahe Oilfield of Tarim Basin is selected as a typical case,and the process of hydrocarbon generation and expulsion,migration and accumulation,adjustment and transformation of deep oil and gas is restored by means of reservoine-forming dynamics simulation.The thermal evolution history of the Lower Cambrian source rocks in Tahe Oilfield reflects the obvious differences in hydrocarbon generation and expulsion process and intensity in different tectonic zones,which is the main reason controlling the differences in deep oil and gas phases.The complex transport system composed of strike-slip fault and unconformity,etc.controlled early migration and accumulation and late adjustment of deep oil and gas,while the Middle Cambrian gypsum-salt rock in inner carbonate platform prevented vertical migration and accumulation of deep oil and gas,resulting in an obvious"fault-controlled"feature of deep oil and gas,in which the low potential area superimposed by the NE-strike-slip fault zone and deep oil and gas migration was conducive to accumulation,and it is mainly beaded along the strike-slip fault zone in the northeast direction.The dynamic simulation of reservoir formation reveals that the spatio-temporal configuration of"source-fault-fracture-gypsum-preservation"controls the differential accumulation of deep oil and gas in Tahe Oilfield.The Ordovician has experienced the accumulation history of multiple periods of charging,vertical migration and accumulation,and lateral adjustment and transformation,and deep oil and gas have always been in the dynamic equilibrium of migration,accumulation and escape.The statistics of residual oil and gas show that the deep stratum of Tahe Oilfield still has exploration and development potential in the Ordovician Yingshan Formation and Penglaiba Formation,and the Middle and Upper Cambrian ultra-deep stratum has a certain oil and gas resource prospect.This study provides a reference for the dynamic quantitative evaluation of deep oil and gas in the Tarim Basin,and also provides a reference for the study of reservoir formation and evolution in carbonate reservoir of paleo-craton basin.展开更多
As the main link of ground engineering,crude oil gathering and transportation systems require huge energy consumption and complex structures.It is necessary to establish an energy efficiency evaluation system for crud...As the main link of ground engineering,crude oil gathering and transportation systems require huge energy consumption and complex structures.It is necessary to establish an energy efficiency evaluation system for crude oil gathering and transportation systems and identify the energy efficiency gaps.In this paper,the energy efficiency evaluation system of the crude oil gathering and transportation system in an oilfield in western China is established.Combined with the big data analysis method,the GA-BP neural network is used to establish the energy efficiency index prediction model for crude oil gathering and transportation systems.The comprehensive energy consumption,gas consumption,power consumption,energy utilization rate,heat utilization rate,and power utilization rate of crude oil gathering and transportation systems are predicted.Considering the efficiency and unit consumption index of the crude oil gathering and transportation system,the energy efficiency evaluation system of the crude oil gathering and transportation system is established based on a game theory combined weighting method and TOPSIS evaluation method,and the subjective weight is determined by the triangular fuzzy analytic hierarchy process.The entropy weight method determines the objective weight,and the combined weight of game theory combines subjectivity with objectivity to comprehensively evaluate the comprehensive energy efficiency of crude oil gathering and transportation systems and their subsystems.Finally,the weak links in energy utilization are identified,and energy conservation and consumption reduction are improved.The above research provides technical support for the green,efficient and intelligent development of crude oil gathering and transportation systems.展开更多
technique.However,the main challenge in this process is the high minimum miscibility pressure(MMP)between natural gas and crude oil,which limits its application and recovery factor,especially in hightemperature reserv...technique.However,the main challenge in this process is the high minimum miscibility pressure(MMP)between natural gas and crude oil,which limits its application and recovery factor,especially in hightemperature reservoirs.Therefore,we present a novel investigation to quantify the effect of chemicalassisted MMP reduction on the oil recovery factor.Firstly,we measured the interfacial tension(IFT)of the methane-oil system in the presence of chemical or CO_(2) to calculate the MMP reduction at a constant temperature(373K)using the vanishing interfacial tension(VIT)method.Afterwards,we performed three coreflooding experiments to quantify the effect of MMP reduction on the oil recovery factor under different injection scenarios.The interfacial tension measurements show that adding a small fraction(1.5 wt%)of the tested surfactant(SOLOTERRA ME-6)achieved 9%of MMP reduction,while adding 20 wt%of CO_(2) to the methane yields 13%of MMP reduction.Then,the coreflooding results highlight the significance of achieving miscibility during gas injection,as the ultimate recovery factor increased from 65.5%under immiscible conditions to 77.2%using chemical-assisted methane,and to 79%using gas mixture after achieving near miscible condition.The results demonstrate the promising potential of the MMP reduction to signifi-cantly increase the oil recovery factor during gas injection.Furthermore,these results will likely expand the application envelop of the miscible gas injection,in addition to the environmental benefits of utilizing the produced gas by re-injection/recycling instead of flaring which contributes to reducing the greenhouse gas emissions.展开更多
This work studied the thickening progression mechanism of the silica fume-oil well cement composite system at high temperatures(110-180.C)in order to provide a theoretical guidance for the rational application of sili...This work studied the thickening progression mechanism of the silica fume-oil well cement composite system at high temperatures(110-180.C)in order to provide a theoretical guidance for the rational application of silica fume in the cementing engineering.Results showed that silica fume seldom affected the thickening progression of oil well cement slurry at 110-120.C,but when temperature reached above130.C,it would aggravate the bulging degree of thickening curves and significantly extend the thickening time,meanwhile causing the abnormal“temperature-based thickening time reversal”and“dosage-based thickening time reversal”phenomena in the range of 130-160.C and 170-180.C respectively.At 130-160.C,the thickening time of oil well cement slurry was mainly associated with the generation rate of calcium hydroxide(CH)crystal.The introduced silica fume would be attracted to the cement minerals'surface that were hydrating to produce CH and agglomerate together to form an“adsorptive barrier”to hinder further hydration of the inner cement minerals.This“adsorptive barrier”effect strengthened with the rising temperature which extended the thickening time and caused the occurrence of the“temperature-based thickening time reversal”phenomenon.At 170-180.C,the pozzolanic activity of silica fume significantly enhanced and considerable amount of C-S-H was generated,thus the“temperature-based thickening time reversal”vanished and the“dosage-based thickening time reversal”was presented.展开更多
Acquiring accurate molecular-level information about petroleum is crucial for refining and chemical enterprises to implement the“selection of the optimal processing route”strategy.With the development of data predic...Acquiring accurate molecular-level information about petroleum is crucial for refining and chemical enterprises to implement the“selection of the optimal processing route”strategy.With the development of data prediction systems represented by machine learning,it has become possible for real-time prediction systems of petroleum fraction molecular information to replace analyses such as gas chromatography and mass spectrometry.However,the biggest difficulty lies in acquiring the data required for training the neural network.To address these issues,this work proposes an innovative method that utilizes the Aspen HYSYS and full two-dimensional gas chromatography-time-of-flight mass spectrometry to establish a comprehensive training database.Subsequently,a deep neural network prediction model is developed for heavy distillate oil to predict its composition in terms of molecular structure.After training,the model accurately predicts the molecular composition of catalytically cracked raw oil in a refinery.The validation and test sets exhibit R2 values of 0.99769 and 0.99807,respectively,and the average relative error of molecular composition prediction for raw materials of the catalytic cracking unit is less than 7%.Finally,the SHAP(SHapley Additive ExPlanation)interpretation method is used to disclose the relationship among different variables by performing global and local weight comparisons and correlation analyses.展开更多
Fatty acids are the main constituents of vegetable oils.To determine the fatty acid compositions of small trade vegetable oils and some less well studied beneficial vegetable oils,and investigate their relationships w...Fatty acids are the main constituents of vegetable oils.To determine the fatty acid compositions of small trade vegetable oils and some less well studied beneficial vegetable oils,and investigate their relationships with antioxidant activity and oxidative stability,gas chromatography-mass spectrometry was performed to characterize the associated fatty acid profiles.The antioxidant activity of vegetable oils,based on their DPPH-scavenging capacity(expressed as IC_(50) values),was used to assess their impact on human health,and their oxidative stability was characterized by performing lipid oxidation analysis to determine the oxidative induction time of fats and oils.In addition,correlation analyses were performed to examine associations between the fatty acid composition of the oils and DPPH-scavenging capacity and oxidative stability.The results revealed that among the assessed oils,coffee seed oil has the highest saturated fatty acid content(355.10 mg/g),whereas Garddenia jaminoides oil has the highest unsaturated fatty acid content(844.84 mg/g).Coffee seed oil was also found have the lowest DPPH IC_(50) value(2.30 mg/mL)and the longest oxidation induction time(17.09 h).Correlation analysis revealed a significant linear relationship(P<0.05)between oxidative stability and unsaturated fatty acid content,with lower contents tending to be associated with better oxidative stability.The findings of this study provide reference data for the screening of functional edible vegetable oils.展开更多
The global energy demand is increasing rapidly,and it is imperative to develop shale hydrocarbon re-sources vigorously.The prerequisite for enhancing the exploitation efficiency of shale reservoirs is the systematic e...The global energy demand is increasing rapidly,and it is imperative to develop shale hydrocarbon re-sources vigorously.The prerequisite for enhancing the exploitation efficiency of shale reservoirs is the systematic elucidation of the occurrence characteristics,flow behavior,and enhanced oil recovery(EOR)mechanisms of shale oil within commonly developed nanopores.Molecular dynamics(MD)technique can simulate the occurrence,flow,and extraction processes of shale oil at the nanoscale,and then quantitatively characterize various fluid properties,flow characteristics,and action mechanisms under different reservoir conditions by calculating and analyzing a series of MD parameters.However,the existing review on the application of MD simulation in shale oil reservoirs is not systematic enough and lacks a summary of technical challenges and solutions.Therefore,recent MD studies on shale oil res-ervoirs were summarized and analyzed.Firstly,the applicability of force fields and ensembles of MD in shale reservoirs with different reservoir conditions and fluid properties was discussed.Subsequently,the calculation methods and application examples of MD parameters characterizing various properties of fluids at the microscale were summarized.Then,the application of MD simulation in the study of shale oil occurrence characteristics,flow behavior,and EOR mechanisms was reviewed,along with the elucidation of corresponding micro-mechanisms.Moreover,influencing factors of pore structure,wall properties,reservoir conditions,fluid components,injection/production parameters,formation water,and inorganic salt ions were analyzed,and some new conclusions were obtained.Finally,the main challenges associated with the application of MD simulations to shale oil reservoirs were discussed,and reasonable prospects for future MD research directions were proposed.The purpose of this review is to provide theoretical basis and methodological support for applying MD simulation to study shale oil reservoirs.展开更多
文摘An effective parameter in the miscible-CO_2 enhanced oil recovery procedure is the minimum miscibility pressure(MMP)defined as the lowest pressure that the oil in place and the injected gas into reservoir achieve miscibility at a given temperature. Flue gases released from power plants can provide an available source of CO_2,which would otherwise be emitted to the atmosphere, for injection into a reservoir. However, the costs related to gas extraction from flue gases is potentially high. Hence, greater understanding the role of impurities in miscibility characteristics between CO_2 and reservoir fluids helps to establish which impurities are tolerable and which are not. In this study, we simulate the effects of the impurities nitrogen(N_2), methane(C_1), ethane(C_2) and propane(C_3) on CO_2 MMP. The simulation results reveal that,as an impurity, nitrogen increases CO_2–oil MMP more so than methane. On the other hand, increasing the propane(C_3)content can lead to a significant decrease in CO_2 MMP, whereas varying the concentrations of ethane(C_2) does not have a significant effect on the minimum miscibility pressure of reservoir crude oil and CO_2 gas. The novel relationships established are particularly valuable in circumstances where MMP experimental data are not available.
基金financial support from the Major Subject of National Science and Technology (2011ZX05032-001)the Fundamental Research Funds for the Central Universities(NO.11CX06022A)
文摘The diffusion coefficient of natural gas in foamy oil is one of the key parameters to evaluate the feasibility of gas injection for enhanced oil recovery in foamy oil reservoirs. In this paper, a PVT cell was used to measure diffusion coefficients of natural gas in Venezuela foamy oil at high pressures, and a new method for deter- mining the diffusion coefficient in the foamy oil was de- veloped on the basis of experimental data. The effects of pressure and the types of the liquid phase on the diffusion coefficient of the natural gas were discussed. The results indicate that the diffusion coefficients of natural gas in foamy oil, saturated oil, and dead oil increase linearly with increasing pressure. The diffusion coefficient of natural gas in the foamy oil at 20 MPa was 2.93 times larger than that at 8.65 MPa. The diffusion coefficient of the natural gas in dead oil was 3.02 and 4.02 times than that of the natural gas in saturated oil and foamy oil when the pressure was 20 MPa. However, the gas content of foamy oil was 16.9 times higher than that of dead oil when the dissolution time and pressure were 20 MPa and 35.22 h, respectively.
基金The financial supports from the Scientific research start-up funding of Zhoukou Normal University (ZKNUC2016022)National Natural Science Foundation of China (21536003, 21706057, and 21606078)the Natural Science Foundation of Guangxi Province (2016GXNSFAA380190) are gratefully acknowledged
文摘An accurate and reliable estimation of minimum miscibility pressure(MMP) of CO2-oil system is a critical task for the design and implementation of CO2 miscible displacement process.In this study,an improved CO2-oil MMP correlation was developed to predict the MMP values for both pure and impure CO2 injection cases based on ten influential factors,i.e.reservoir temperature(TR),molecular weight of C7+oil components(MWC7+),mole fraction of volatile oil components(xvol),mole fraction of C2-C4 oil components(xC2-C4),mole fraction of C5-C6 oil components(xCs-5-C6),and the gas stream mole fractions of CO2(yCO2),H2S(yH2S),C1(yC1),hydrocarbons(yHC)and N2(yN2).The accuracy of the improved correlation was evaluated against experimental data reported in literature concurrently with those estimated by several renowned correlations.It was found that the improved correlation provided higher prediction accuracy and consistency with literature experimental data than other literature correlations.In addition,the predictive capability of the improved correlation was further validated by predicting an experimentally measured CO2-Oil MMP data,and it showed an accurate result with the absolute deviation of 4.15%.Besides,the differential analysis of the improved correlation was analyzed to estimate the impact of parameters uncertainty in the original MMP data on the calculated results.Also,sensitivity analysis was performed to analyze the influence of each parameter on MMP qualitatively and quantitatively.The results revealed that the increase of xC2-C4,xC5-C6 and yH2 S lead to the decrease of MMP,while the increase of TR,MWC7+,xvol,yCO2,YC1,yHC and yN2 tend to increase the MMP.Overall,the relevance of each parameter with MMP follows the order of TR> xC5-C6> MWC7+> xvol> yH2 S> yHC> yCO2>yC1>yN2>xC2-C4.
基金supported by the General Program of the National Natural Science Foundation of China(52074335)the National Key Research and Development Program of China(2022YFE0129900 and 2019YFA0708700)+1 种基金the Fundamental Research Funds for the Central Universities(23CX07003A)the Special Funding Program for the Operational Expenses of National Research Institutions(SKLDOG2024-ZYRC-01).
文摘In deep oil reservoir development,enhanced oil recovery(EOR)techniques encounter significant challenges under high-temperature and high-salinity conditions.Traditional profile-control agents often fail to maintain stable blocking under extreme conditions and exhibit poor resistance to high temperature and high salinity.This study develops a functionalized nanographite system(the MEGO system)with superior high-temperature dispersibility and thermosalinity-responsive capability through polyether amine(PEA)grafting and noncovalent interactions with disodium naphthalene sulfonate(DNS)molecules.The grafted PEA and DNS provide steric hindrance and electrostatic repulsion,enhancing thermal and salinity resistance.After ten days of aggregation,the MEGO system forms stable particle aggregates(55.51-61.80 lm)that are suitable for deep reservoir migration and profile control.Both experiments and simulations reveal that particle size variations are synergistically controlled by temperature and salt ions(Na^(+),Ca^(2+),and Mg^(2+)).Compared with monovalent ions,divalent ions promote nanographite aggregation more strongly through double-layer compression and bridging effects.In core displacement experiments,the MEGO system demonstrated superior performance in reservoirs with permeabilities ranging from 21.6 to 103 mD.The aggregates formed within the pore throats significantly enhanced flow resistance,expanded the sweep volume,and increased the overall oil recovery to 56.01%.This research indicates that the MEGO system holds excellent potential for EOR in deep oil reservoirs.
基金supported by the National Natural Science Foundation of China(31871778,31801468,and 32072201)Foshan Social Field Technology R&D Special Program(2120001008478)+1 种基金Science and Technology Program of Guangzhou,China(202201011762)State Key Laboratory of Dampness Syndrome of Chinese Medicine,The Second Affiliated Hospital of Guangzhou University of Chinese Medicine(SZ2024KF05)。
文摘Semen Platycladi(SP)is the dried ripe kernel of Platycladus orientalis(L.)Franco,has been used for insomnia treatment for bimillennium in China,which mechanism is not fully understood.The aim of this study was to explore the sleep-promoting mechanism of essential oil and saponins from SP.As 2 main bioactive constituents of SP,essential oil(SPO)and saponin(SPS)were extracted,then was given to p-chlorophenylalanine(PCPA)-induced insomnia mice by intragastric administration.Then,the behavioral tests,neurotransmitter receptors,cytokines and hormone in brain were investigated.Behavior test showed that SPO and SPS exhibited sleep-enhancing effect through suppressing depression,shortening the onset time while prolonging the sleep duration in insomnia mice.Also SPO and SPS up-regulated serotonin(5-HT)receptors in serotonergic neurons,increased glutamic acid decarboxylase(GAD)content in GABAergic neurons,and stimulatedγ-aminobutyric acid(GABA)receptors expression to enhance the synaptic inhibition.Moreover,they could down-regulated the cytokines and rebalanced hormone expressions.Although both SPO and SPS exerted sleep-promoting,they had different focusing targets.SPS had stronger effect on neurotransmitter receptors regulation while SPO had better hormone rebalanced ability.Briefly,SPO and SPS exerted sedative-hypnotic effect in insomnia mice through modulating multi-targets in serotonergic and GABAergic system.
基金supported by the Basic Research Funds for the Central Government“Innovative Team of Zhejiang University”under contract number(2022FZZX01-09).
文摘Data center cooling systems are substantial energy consumers,and managing the heat generated by electronic devices is becoming more complex as chip power levels continue to rise.The single-phase immersion cooling(SPIC)server with oil coolant is numerically investigated using the validated Re-Normalization Group(RNG)k-εmodel.For the investigated scenarios where coolant velocity at the tank inlet is 0.004 m/s and the total power is 740 W,the heat transfer between the heat sinks and the coolant is dominated by natural convection,although forced convection mediates the overall heat transfer inside the tank.The maximum velocity of coolant through the heat sink is 0.035 m/s and the average heat transfer coefficient is up to 75.8 W/(m2·K).The geometry of the heat sink is important for the cooling performance.Increasing both the fin thickness and number enhances the natural convection effect of the heat sink,but also increases the flow resistance.The heat sink with a fin thickness of 3 mm performs the best,reducing the average graphics processing unit(GPU)temperature from 71.3℃ to 68.6℃.A heat sink with an optimal fin number of 16 reduces the average GPU temperature to 67.7℃.As for the effect of fin height,increasing it from 15 to 30 mm results in increases in the heat transfer area and flow rate by about 72%and 32%,respectively,which reduces the average GPU temperature to 65.2℃.Therefore,the importance of fin parameters ranks in the following order:fin height,number,and thickness.This study highlights the potential application of oil coolants in SPIC systems and offers theoretical guidance for the efficient design of natural convection cooling solutions.
文摘BACKGROUND Silicone oil(SiO)migration to the central nervous system(CNS)is a rare complication of SiO tamponade after vitreo-retinal surgeries,it could masquerade hemorrhage on computed tomography neuro-imaging.Only limited cases were reported in the literature,certain intra-operative and post-operative ocular risk factors might contribute to the different extend of SiO migration in the CNS.AIM To study the risk factors for cerebral ventricular migration(CVM)on top of visual pathway migration(VPM).METHODS Conforming to the preferred reporting items for systematic reviews and metaanalyses guidelines,literature searches on PubMed,MEDLINE,EMBASE were performed on June 1,2024.Publications on SiO migration to CNS were included in this review.Non-English articles,and studies without neuro-imaging of the CNS were excluded.Patient demographics,SiO filled eyes'ocular characteristics and vitrectomy surgical details were extracted from included studies in this review.VPM and CVM were assigned as group 1 and group 2 respectively.Fisher's exact tests,Mann-Whitney U tests and binary logistic regression were performed.RESULTS Total 68 articles were obtained after searches,48 publications were included for analysis.Total 54 SiO filled eyes were analyzed.Post-vitrectomy intraocular pressure(IOP)was found to be significant in both Mann-Whitney U test(P=0.047)and binary logistic regression(P=0.012).Diabetic was found to be significant in binary logistic regression(P=0.037),but at borderline risk for CVM in Fisher's exact test(P=0.05).Other significant factors include longer SiO tamponade time(P=0.002 in Fisher's exact test)and visual acuity(P=0.011 in binary logistic regression).Optic nerve atrophy or disc cupping(P=1.00,P=0.790)and congenital optic disc anomalies(P=0.424)were all with P>0.05.CONCLUSION SiO migration to CNS is rare with limited case reports only.Our analysis of the existing literature demonstrated higher post-vitrectomy IOP was associated with CVM,followed by patients’diabetic status,longer SiO tamponade time and visual acuity.Optic nerve atrophy,disc cupping and congenital optic disc anomalies were not associated.Modifiable risk factors of post-vitrectomy IOP and SiO tamponade time should be closely monitored by vitreoretinal surgeons.Lower IOP target post-vitrectomy and earlier SiO removal surgeries should be arranged.
基金Supporting Project number(RSP2025R92)at King Saud University,Riyadh,Saudi Arabia,for their support.
文摘The importance of organic geochemistry and basin modeling is widely recognized and used to understand the source rock potential and hydrocarbon generation history of the Mangahewa Formation,and thereby given the foundational role in the petroleum exploration.This study utilized the total organic carbon(TOC)content and hydrogen index(HI)to investigate the dominant kerogen type and hydrogen richness for the significance of petroleum generative potential.The Mangahewa coals and carbonaceous shales exhibit an excellent source rocks,with high total organic content(TOC)of more than 22%.The coals and carbonaceous shales were also characterised by Type Ⅱ‒Ⅲ kerogen with Type Ⅲ kerogen,promising oiland gas-prones.The Mangahewa Formation reached the main oil generation,with vitrinite reflectances between 0.53%and 1.01%.Vitrinite reflectance was also used in developing themal models and reveal the transformation(TR)of 10‒50%kerogen to oil during the Late Miocene.The models also showed that the Mangahewa source rock has a significant oil generation and little expulsion competency,with a TR of up to 54%.These findings support the substantial oil-generating potential in the Taranaki Basin's southern graben and can be used as a guide when developing strategies for an oil exploration program.
文摘By investigating the performance characteristics of the bio-based surfactant 8901A,a composite decontamination and injection system was developed using 8901A as the primary agent,tailored for application in low-permeability and heavy oil reservoirs under varying temperature conditions.The results demonstrate that this system effectively reduces oil–water interfacial tension,achieving an ultra-low interfacial tension state.The static oil washing efficiency of oil sands exceeds 85%,the average pressure reduction rate reaches 21.55%,and the oil recovery rate improves by 13.54%.These enhancements significantly increase the system’s ability to dissolve oilbased blockages,thereby lowering water injection pressure caused by organic fouling,increasing the injection volume of injection wells,and ultimately improving oil recovery efficiency.
基金Supported by the National Natural Science Foundation of China (Grant No. 52071097)Hainan Provincial Natural Science Foundation of China (Grant No. 522MS162)Research Fund from Science and Technology on Underwater Vehicle Technology Laboratory (Grant No. 2021JCJQ-SYSJJ-LB06910)。
文摘Path planning for recovery is studied on the engineering background of double unmanned surface vehicles(USVs)towing oil booms for oil spill recovery.Given the influence of obstacles on the sea,the improved artificial potential field(APF)method is used for path planning.For addressing the two problems of unreachable target and local minimum in the APF,three improved algorithms are proposed by combining the motion performance constraints of the double USV system.These algorithms are then combined as the final APF-123 algorithm for oil spill recovery.Multiple sets of simulation tests are designed according to the flaws of the APF and the process of oil spill recovery.Results show that the proposed algorithms can ensure the system’s safety in tracking oil spills in a complex environment,and the speed is increased by more than 40%compared with the APF method.
基金financially supported by the National Natural Science Foundation of China(No.U20B6003)the China Scholarship Council(No.202306440015)a project of the China Petroleum&Chemical Corporation(No.P22174)。
文摘The hybrid CO_(2) thermal technique has achieved considerable success globally in extracting residual heavy oil from reserves following a long-term steam stimulation process.Using microscopic visualization experiments and molecular dynamics(MD)simulations,this study investigates the microscopic enhanced oil recovery(EOR)mechanisms underlying residual oil removal using hybrid CO_(2) thermal systems.Based on the experimental models for the occurrence of heavy oil,this study evaluates the performance of hybrid CO_(2) thermal systems under various conditions using MD simulations.The results demonstrate that introducing CO_(2) molecules into heavy oil can effectively penetrate and decompose dense aggregates that are originally formed on hydrophobic surfaces.A stable miscible hybrid CO_(2) thermal system,with a high effective distribution ratio of CO_(2),proficiently reduces the interaction energies between heavy oil and rock surfaces,as well as within heavy oil.A visualization analysis of the interactions reveals that strong van der Waals(vdW)attractions occur between CO_(2) and heavy oil molecules,effectively promoting the decomposition and swelling of heavy oil.This unlocks the residual oil on the hydrophobic surfaces.Considering the impacts of temperature and CO_(2) concentration,an optimal gas-to-steam injection ratio(here,the CO_(2):steam ratio)ranging between 1:6 and 1:9 is recommended.This study examines the microscopic mechanisms underlying the hybrid CO_(2) thermal technique at a molecular scale,providing a significant theoretical guide for its expanded application in EOR.
基金financially supported by National Natural Science Foundation of China(No.22302229)Beijing Municipal Excellent Talent Training Funds Youth Advanced Individual Project(No.2018000020124G163)。
文摘Emulsification is one of the important mechanisms of surfactant flooding. To improve oil recovery for low permeability reservoirs, a highly efficient emulsification oil flooding system consisting of anionic surfactant sodium alkyl glucosyl hydroxypropyl sulfonate(APGSHS) and zwitterionic surfactant octadecyl betaine(BS-18) is proposed. The performance of APGSHS/BS-18 mixed surfactant system was evaluated in terms of interfacial tension, emulsification capability, emulsion size and distribution, wettability alteration, temperature-resistance and salt-resistance. The emulsification speed was used to evaluate the emulsification ability of surfactant systems, and the results show that mixed surfactant systems can completely emulsify the crude oil into emulsions droplets even under low energy conditions. Meanwhile,the system exhibits good temperature and salt resistance. Finally, the best oil recovery of 25.45% is achieved for low permeability core by the mixed surfactant system with a total concentration of 0.3 wt%while the molar ratio of APGSHS:BS-18 is 4:6. The current study indicates that the anionic/zwitterionic mixed surfactant system can improve the oil flooding efficiency and is potential candidate for application in low permeability reservoirs.
基金financially supported by the National Key Research and Development Program of China(Grant No.2022YFE0129800)the National Natural Science Foundation of China(Grant No.42202204)。
文摘In-situ upgrading by heating is feasible for low-maturity shale oil,where the pore space dynamically evolves.We characterize this response for a heated substrate concurrently imaged by SEM.We systematically follow the evolution of pore quantity,size(length,width and cross-sectional area),orientation,shape(aspect ratio,roundness and solidity)and their anisotropy—interpreted by machine learning.Results indicate that heating generates new pores in both organic matter and inorganic minerals.However,the newly formed pores are smaller than the original pores and thus reduce average lengths and widths of the bedding-parallel pore system.Conversely,the average pore lengths and widths are increased in the bedding-perpendicular direction.Besides,heating increases the cross-sectional area of pores in low-maturity oil shales,where this growth tendency fluctuates at<300℃ but becomes steady at>300℃.In addition,the orientation and shape of the newly-formed heating-induced pores follow the habit of the original pores and follow the initial probability distributions of pore orientation and shape.Herein,limited anisotropy is detected in pore direction and shape,indicating similar modes of evolution both bedding-parallel and bedding-normal.We propose a straightforward but robust model to describe evolution of pore system in low-maturity oil shales during heating.
基金Supported by the Sichuan Province Regional Innovation Cooperation Project(21QYCX0048)Sinopec Science and Technology Department Project(P21048-3)。
文摘According to the complex differential accumulation history of deep marine oil and gas in superimposed basins,the Lower Paleozoic petroleum system in Tahe Oilfield of Tarim Basin is selected as a typical case,and the process of hydrocarbon generation and expulsion,migration and accumulation,adjustment and transformation of deep oil and gas is restored by means of reservoine-forming dynamics simulation.The thermal evolution history of the Lower Cambrian source rocks in Tahe Oilfield reflects the obvious differences in hydrocarbon generation and expulsion process and intensity in different tectonic zones,which is the main reason controlling the differences in deep oil and gas phases.The complex transport system composed of strike-slip fault and unconformity,etc.controlled early migration and accumulation and late adjustment of deep oil and gas,while the Middle Cambrian gypsum-salt rock in inner carbonate platform prevented vertical migration and accumulation of deep oil and gas,resulting in an obvious"fault-controlled"feature of deep oil and gas,in which the low potential area superimposed by the NE-strike-slip fault zone and deep oil and gas migration was conducive to accumulation,and it is mainly beaded along the strike-slip fault zone in the northeast direction.The dynamic simulation of reservoir formation reveals that the spatio-temporal configuration of"source-fault-fracture-gypsum-preservation"controls the differential accumulation of deep oil and gas in Tahe Oilfield.The Ordovician has experienced the accumulation history of multiple periods of charging,vertical migration and accumulation,and lateral adjustment and transformation,and deep oil and gas have always been in the dynamic equilibrium of migration,accumulation and escape.The statistics of residual oil and gas show that the deep stratum of Tahe Oilfield still has exploration and development potential in the Ordovician Yingshan Formation and Penglaiba Formation,and the Middle and Upper Cambrian ultra-deep stratum has a certain oil and gas resource prospect.This study provides a reference for the dynamic quantitative evaluation of deep oil and gas in the Tarim Basin,and also provides a reference for the study of reservoir formation and evolution in carbonate reservoir of paleo-craton basin.
基金This work was financially supported by the National Natural Science Foundation of China(52074089 and 52104064)Natural Science Foundation of Heilongjiang Province of China(LH2019E019).
文摘As the main link of ground engineering,crude oil gathering and transportation systems require huge energy consumption and complex structures.It is necessary to establish an energy efficiency evaluation system for crude oil gathering and transportation systems and identify the energy efficiency gaps.In this paper,the energy efficiency evaluation system of the crude oil gathering and transportation system in an oilfield in western China is established.Combined with the big data analysis method,the GA-BP neural network is used to establish the energy efficiency index prediction model for crude oil gathering and transportation systems.The comprehensive energy consumption,gas consumption,power consumption,energy utilization rate,heat utilization rate,and power utilization rate of crude oil gathering and transportation systems are predicted.Considering the efficiency and unit consumption index of the crude oil gathering and transportation system,the energy efficiency evaluation system of the crude oil gathering and transportation system is established based on a game theory combined weighting method and TOPSIS evaluation method,and the subjective weight is determined by the triangular fuzzy analytic hierarchy process.The entropy weight method determines the objective weight,and the combined weight of game theory combines subjectivity with objectivity to comprehensively evaluate the comprehensive energy efficiency of crude oil gathering and transportation systems and their subsystems.Finally,the weak links in energy utilization are identified,and energy conservation and consumption reduction are improved.The above research provides technical support for the green,efficient and intelligent development of crude oil gathering and transportation systems.
基金supported by a joint project with Southwest Petroleum University (China)funded by Tarim Oilfield Company (PetroChina).
文摘technique.However,the main challenge in this process is the high minimum miscibility pressure(MMP)between natural gas and crude oil,which limits its application and recovery factor,especially in hightemperature reservoirs.Therefore,we present a novel investigation to quantify the effect of chemicalassisted MMP reduction on the oil recovery factor.Firstly,we measured the interfacial tension(IFT)of the methane-oil system in the presence of chemical or CO_(2) to calculate the MMP reduction at a constant temperature(373K)using the vanishing interfacial tension(VIT)method.Afterwards,we performed three coreflooding experiments to quantify the effect of MMP reduction on the oil recovery factor under different injection scenarios.The interfacial tension measurements show that adding a small fraction(1.5 wt%)of the tested surfactant(SOLOTERRA ME-6)achieved 9%of MMP reduction,while adding 20 wt%of CO_(2) to the methane yields 13%of MMP reduction.Then,the coreflooding results highlight the significance of achieving miscibility during gas injection,as the ultimate recovery factor increased from 65.5%under immiscible conditions to 77.2%using chemical-assisted methane,and to 79%using gas mixture after achieving near miscible condition.The results demonstrate the promising potential of the MMP reduction to signifi-cantly increase the oil recovery factor during gas injection.Furthermore,these results will likely expand the application envelop of the miscible gas injection,in addition to the environmental benefits of utilizing the produced gas by re-injection/recycling instead of flaring which contributes to reducing the greenhouse gas emissions.
基金supported by the Basic Research and Strategic Reserve Technology Research Fund Project of China National Petroleum Corporation (Grant No.2021DQ03-14)the National Natu ral Science Foundation of China (Grant No.52204010)Haihe Laboratory of Sustainable Chemical Transformations for financial support。
文摘This work studied the thickening progression mechanism of the silica fume-oil well cement composite system at high temperatures(110-180.C)in order to provide a theoretical guidance for the rational application of silica fume in the cementing engineering.Results showed that silica fume seldom affected the thickening progression of oil well cement slurry at 110-120.C,but when temperature reached above130.C,it would aggravate the bulging degree of thickening curves and significantly extend the thickening time,meanwhile causing the abnormal“temperature-based thickening time reversal”and“dosage-based thickening time reversal”phenomena in the range of 130-160.C and 170-180.C respectively.At 130-160.C,the thickening time of oil well cement slurry was mainly associated with the generation rate of calcium hydroxide(CH)crystal.The introduced silica fume would be attracted to the cement minerals'surface that were hydrating to produce CH and agglomerate together to form an“adsorptive barrier”to hinder further hydration of the inner cement minerals.This“adsorptive barrier”effect strengthened with the rising temperature which extended the thickening time and caused the occurrence of the“temperature-based thickening time reversal”phenomenon.At 170-180.C,the pozzolanic activity of silica fume significantly enhanced and considerable amount of C-S-H was generated,thus the“temperature-based thickening time reversal”vanished and the“dosage-based thickening time reversal”was presented.
基金the National Natural Science Foundation of China(22108307)the Natural Science Foundation of Shandong Province(ZR2020KB006)the Outstanding Youth Fund of Shandong Provincial Natural Science Foundation(ZR2020YQ17).
文摘Acquiring accurate molecular-level information about petroleum is crucial for refining and chemical enterprises to implement the“selection of the optimal processing route”strategy.With the development of data prediction systems represented by machine learning,it has become possible for real-time prediction systems of petroleum fraction molecular information to replace analyses such as gas chromatography and mass spectrometry.However,the biggest difficulty lies in acquiring the data required for training the neural network.To address these issues,this work proposes an innovative method that utilizes the Aspen HYSYS and full two-dimensional gas chromatography-time-of-flight mass spectrometry to establish a comprehensive training database.Subsequently,a deep neural network prediction model is developed for heavy distillate oil to predict its composition in terms of molecular structure.After training,the model accurately predicts the molecular composition of catalytically cracked raw oil in a refinery.The validation and test sets exhibit R2 values of 0.99769 and 0.99807,respectively,and the average relative error of molecular composition prediction for raw materials of the catalytic cracking unit is less than 7%.Finally,the SHAP(SHapley Additive ExPlanation)interpretation method is used to disclose the relationship among different variables by performing global and local weight comparisons and correlation analyses.
文摘Fatty acids are the main constituents of vegetable oils.To determine the fatty acid compositions of small trade vegetable oils and some less well studied beneficial vegetable oils,and investigate their relationships with antioxidant activity and oxidative stability,gas chromatography-mass spectrometry was performed to characterize the associated fatty acid profiles.The antioxidant activity of vegetable oils,based on their DPPH-scavenging capacity(expressed as IC_(50) values),was used to assess their impact on human health,and their oxidative stability was characterized by performing lipid oxidation analysis to determine the oxidative induction time of fats and oils.In addition,correlation analyses were performed to examine associations between the fatty acid composition of the oils and DPPH-scavenging capacity and oxidative stability.The results revealed that among the assessed oils,coffee seed oil has the highest saturated fatty acid content(355.10 mg/g),whereas Garddenia jaminoides oil has the highest unsaturated fatty acid content(844.84 mg/g).Coffee seed oil was also found have the lowest DPPH IC_(50) value(2.30 mg/mL)and the longest oxidation induction time(17.09 h).Correlation analysis revealed a significant linear relationship(P<0.05)between oxidative stability and unsaturated fatty acid content,with lower contents tending to be associated with better oxidative stability.The findings of this study provide reference data for the screening of functional edible vegetable oils.
基金supported by the National Natural Science Foundation of China(52304021,52104022,52204031)the Natural Science Foundation of Sichuan Province(2022NSFSC0205,2024NSFSC0201,2023NSFSC0947)the National Science and Technology Major Projects of China(2017ZX05049006-010).
文摘The global energy demand is increasing rapidly,and it is imperative to develop shale hydrocarbon re-sources vigorously.The prerequisite for enhancing the exploitation efficiency of shale reservoirs is the systematic elucidation of the occurrence characteristics,flow behavior,and enhanced oil recovery(EOR)mechanisms of shale oil within commonly developed nanopores.Molecular dynamics(MD)technique can simulate the occurrence,flow,and extraction processes of shale oil at the nanoscale,and then quantitatively characterize various fluid properties,flow characteristics,and action mechanisms under different reservoir conditions by calculating and analyzing a series of MD parameters.However,the existing review on the application of MD simulation in shale oil reservoirs is not systematic enough and lacks a summary of technical challenges and solutions.Therefore,recent MD studies on shale oil res-ervoirs were summarized and analyzed.Firstly,the applicability of force fields and ensembles of MD in shale reservoirs with different reservoir conditions and fluid properties was discussed.Subsequently,the calculation methods and application examples of MD parameters characterizing various properties of fluids at the microscale were summarized.Then,the application of MD simulation in the study of shale oil occurrence characteristics,flow behavior,and EOR mechanisms was reviewed,along with the elucidation of corresponding micro-mechanisms.Moreover,influencing factors of pore structure,wall properties,reservoir conditions,fluid components,injection/production parameters,formation water,and inorganic salt ions were analyzed,and some new conclusions were obtained.Finally,the main challenges associated with the application of MD simulations to shale oil reservoirs were discussed,and reasonable prospects for future MD research directions were proposed.The purpose of this review is to provide theoretical basis and methodological support for applying MD simulation to study shale oil reservoirs.
