To get deep understanding of the reaction mechanism of coal pyrolysis in hydrogen plasma, the decomposition reaction pathways of aliphatic hydrocarbons and cycloalkanes, which are two main components in volatiles from...To get deep understanding of the reaction mechanism of coal pyrolysis in hydrogen plasma, the decomposition reaction pathways of aliphatic hydrocarbons and cycloalkanes, which are two main components in volatiles from coal, were investigated. Methane and cyclohexane were chosen as the model compounds. Density functional theory was employed, and many reaction pathways were involved. Calculations were carried out in Gaussian 09 at the B3LYP/6-31G（d,p） level of the theory. The results indicate that the main pyrolysis products of methane and cyclohexane in hydrogen plasma are both hydrogen and acetylene, and the participation of active hydrogen atoms makes dehydrogenation reactions more favorable. H2 mainly comes from dehydrogenation process, while many reaction pathways are responsible for acetylene formation. During coal pyrolysis in hydrogen plasma, three main components in volatiles like aliphatic hydrocarbons, cycloalkanes and aromatic hydrocarbons lead to the formation of hydrogen and acetylene, but their contributions to products distribution are different.展开更多
Quantitative representation of complicated behavior of fluid mixtures in the critical region by any of equation-of-state theories re-mains as a difficult thermodynamic topics to date. In the present work, a computatio...Quantitative representation of complicated behavior of fluid mixtures in the critical region by any of equation-of-state theories re-mains as a difficult thermodynamic topics to date. In the present work, a computational efforts were made for representing various types of critical loci of binary water with hydrocarbon systems showing Type II and Type III phase behavior by an elementary equation of state [called multi-fluid nonrandom lattice fluid EOS (MF-NLF EOS)] based on the lattice statistical mechanical theory. The model EOS requires two mo-lecular parameters which representing molecular size and interaction energy for a pure component and single adjustable interaction energy pa-rameter for binary mixtures. Critical temperature and pressure data were used to obtain molecular size parameter and vapor pressure data were used to obtain interaction energy parameter. The MF-NLF EOS model adapted in the present study correlated quantitatively well the critical loci of various binary water with hydrocarbon systems.展开更多
Based on the research progress of the geological theory of coal-formed gas,the contributions of coal-formed gas to the natural gas reserves and production in China and to the development of natural gas in major gas-pr...Based on the research progress of the geological theory of coal-formed gas,the contributions of coal-formed gas to the natural gas reserves and production in China and to the development of natural gas in major gas-producing basins are analyzed,and the key favorable exploration zones for coal-formed gas in China are comprehensively evaluated.The following results are obtained.First,coal measures are good gas source rocks,and hydrocarbon generation from coal measure was dominated by gas,followed by oil.Second,a natural gas genetic identification index system based on stable isotopes,light hydrocarbon components,and biomarkers is established.Third,the quantitative and semi-quantitative factors controlling the formation of large gas fields,represented by the indicator of gas generation intensity greater than 20×10^(8) m^(3)/km^(2),are identified to guide the discovery of large gas fields in China.Fourth,coal-formed gas is the major contributor to the current natural gas reserves and production of China,both accounting for over 55%.The high proportion of coal-formed gas has enabled the Tarim,Sichuan and Ordos basins to be the major gas production areas in China.Fifth,coal rock gas is an important field for future exploration of coal-formed gas,and key zones include the Carboniferous Benxi Formation(Fm.)in the Wushenqi-Mizhi area of the Ordos Basin,the Permian Longtan Fm.in central-southern Sichuan Basin,the Jurassic Xishanyao Fm.in the southern margin and Luliang uplift of the Junggar Basin.Sixth,tight gas is the main area for increasing reserves and production,and the favorable exploration zones include the Carboniferous-Permian in southern Ordos Basin and the Bohai Bay Basin,and the Triassic Xujiahe Fm.in the transition zone between central and western Sichuan Basin.Seventh,the Jurassic in the southern margin of the Junggar Basin is a key favorable exploration zone for subsequent investigation of conventional coal-formed gas.These insights have valuable theoretical and practical significance for further developing and improving the theory of coal-formed gas,and guiding the exploration of coal-formed gas fields in China.展开更多
Periodic density functional theory was applied to investigate the reaction mechanism for the methylation of toluene with methanol over HZSM-5.The results indicated that toluene could be methylated at its para,meta,ort...Periodic density functional theory was applied to investigate the reaction mechanism for the methylation of toluene with methanol over HZSM-5.The results indicated that toluene could be methylated at its para,meta,ortho and geminal positions via a concerted or stepwise pathway.For the concerted pathway,the calculated free energy barriers for the para,meta,ortho and geminal methylation reactions were 167,138,139 and 183 kJ/mol,respectively.For the stepwise pathway,the dehydration of methanol was found to be the rate-determining step with a free energy barrier of145 kj/mol,whereas the free energy barriers for the methylation of toluene at its para,meta,ortho and geminal positions were 127,105,106 and 114 kj/mol,respectively.Both pathways led to the formation of C8H11^＋ species as important intermediates,which could back-donate a proton to the zeolite framework via a reorientation process or form gaseous products through demethylation.Methane was formed via an intramolecular hydrogen transfer reaction from a ring carbon of the C8H11^＋ species to the carbon of the methyl group,with calculated energy barriers of 136,132 and134 kj/mol for the para,meta and ortho C8H11^＋ species,respectively.The calculated free energy barriers for the formation of para-,meta- and ortho-xylene indicated that the formation of the para-xylene had the highest energy barrier for both pathways.展开更多
Investigation of spatial distribution of oil and gas resource and accurate prediction of the geographic location of its undiscovered resource is significant for reducing exploration risk and improving exploration bene...Investigation of spatial distribution of oil and gas resource and accurate prediction of the geographic location of its undiscovered resource is significant for reducing exploration risk and improving exploration benefit.A new method for predicting spatial distribution of oil resource is discussed in this paper.It consists of prediction of risk probability in petroleum exploration and simulation of hydrocarbon abundance. Exploration risk probability is predicted by multivariate statistics,fuzzy mathematics and information processing techniques.A spatial attribute database for sample wells was set up and the Mahalanobis distance and Fuzzy value of given samples were obtained.Then,the Bayesian formula was used to calculate the hydrocarbon-bearing probability at the area of exploration wells.Finally,a hydrocarbon probability template is formed and used to forecast the probability of the unknown area. The hydrocarbon abundance is simulated based on Fourier integrals,frequency spectrum synthesis and fractal theory.Firstly,the fast Fourier transformation（FFT） is used to transform the known hydrocarbon abundance from the spatial domain to the frequency domain,then,frequency spectrum synthesis is used to produce the fractal frequency spectrum,and FFT is applied to get the phase information of hydrocarbon-bearing probability.Finally,the frequency spectrum simulation is used to calculate the renewed hydrocarbon abundance in the play. This method is used to predict the abundance and possible locations of the undiscovered petroleum accumulations in the Nanpu Sag of the Bohai Bay Basin,China.The prediction results for the well-explored onshore area of the northern Nanpu Sag agree well with the actual situations.For the less-explored offshore areas in the southern Nanpu Sag,the prediction results suggest high hydrocarbon abundance in Nanpu-1 and Nanpu-2,providing a useful guiding for future exploration.展开更多
Hydrocarbon source rock obviously controls the formation and distribution of hydrocarbon reservoirs. Based on the geological concept of ＂source control theory＂, the concept of a hydrocarbon distribution threshold wa...Hydrocarbon source rock obviously controls the formation and distribution of hydrocarbon reservoirs. Based on the geological concept of ＂source control theory＂, the concept of a hydrocarbon distribution threshold was put forward. This means the maximum range for hydrocarbon controlled by the source rock conditions to migrate in the hydrocarbon basins. Three quantitative analysis models are proposed on this basis, namely the hydrocarbon accumulation probability, maximum hydrocarbon scale threshold and reserve distribution probability, which respectively refer to the probability of forming a hydrocarbon reservoir, the possible maximum scale of the hydrocarbon reservoir and the percentage of reserve distribution in a certain area within the hydrocarbon distribution threshold. Statistical analysis on 539 hydrocarbon reservoirs discovered in 28 hydrocarbon source kitchens from seven sedimentary basins and sags of eastern China shows the maximum reservoir scale possibly formed in the hydrocarbon basin, hydrocarbon accumulation probability and oil and gas reserve distribution probability are all controlled by the characteristics of the hydrocarbon source rock. Generally, as the distances from the hydrocarbon source rock center and hydrocarbon discharge boundary get longer and the hydrocarbon discharge intensity of hydrocarbon source rock center gets smaller, there will be lower probability of hydrocarbon accumulation. Corresponding quantitative models are established based on single factor statistics and multivariate analysis. Practical application in the Jiyang Depression shows that the prediction from the quantitative analysis model for the hydrocarbon distribution threshold agree well with the actual exploration results, indicating that the quantitative analysis model is likely to be a feasible tool.展开更多
The relationship between chemical structures and biodegradation rates （k b） of 22 polycyclic aromatic hydrocarbons （PAHs） was studied using density functional theory （DFT） and stepwise multiple linear regression...The relationship between chemical structures and biodegradation rates （k b） of 22 polycyclic aromatic hydrocarbons （PAHs） was studied using density functional theory （DFT） and stepwise multiple linear regression analysis （SMLR） method.The equilibrium geometries and vibration frequency have been investigated at the B3LYP/6-31＋G（d,p） level by thinking Solvent effects using a selfconsistent reaction field （SCRF） based on the polarizable continuum model （PCM）.It was concluded that the biodegradation rate was closely related to its molecular structure,and there is one high correlation coefficient between the in-plane bending vibration frequency of the conjugated ring of PAHs （Freq） and k b.By means of regression analysis,the main factors affecting the biodegradation rate were obtained and the equation of quantitative structure-activity relationship （QSAR） was successfully established kb =-0.653＋0.001Freq＋0.068CQ＋0.049N1.Statistical evaluation of the developed QSAR showed that the relationships were statistically significant and the model had good predictive ability.The fact that a bending frequency is more important than the HOMO or LUMO energies in predicting k b suggests that the bending of benzene ring might play an important role in the enzymatic catalysis of the initial oxidation step.展开更多
Speed of sound data for butyl acetate＋benzene, or toluene, or o-xylene, or m-xylene, or p-xylene binary mixtures have been measured over the entire range of mole fraction at 308.15 K. The excess isentropic compressib...Speed of sound data for butyl acetate＋benzene, or toluene, or o-xylene, or m-xylene, or p-xylene binary mixtures have been measured over the entire range of mole fraction at 308.15 K. The excess isentropic compressibilities （ Ks^E ） were computed from speed of sound and density data, derived from molar excess volume data. The Ks^E values were analyzed by using graph theoretical approach. The Ks^E values evaluated by graph theory compared reasonably well with their corresponding experimental values. The Ks^E data were also expressed in terms of Redlich-Kister polynomial equation to derive the coefficients and the standard deviation.展开更多
The C--C bond dissociation energy （BDE） is a very important data in research of hydrocarbon cracking reactions, because it reflects the difficulty level of chemical reactions. But it is very difficult to obtain the ...The C--C bond dissociation energy （BDE） is a very important data in research of hydrocarbon cracking reactions, because it reflects the difficulty level of chemical reactions. But it is very difficult to obtain the C--C bond dissociation energy （BDE） by experiments, so using quantum chemistry calculation such as density functional theory （DFT） to study the C--C bond dissociation energy is a very useful means. The impact of acceptor substituents and donor substituents on the C--C bond length distribution was studied.展开更多
Petroleum is not a production of direct transformation of organic material into kerogen or oil. Sea organics can’t form such huge oil fields, since these sea creatures will either be consumed by bigger ones or decaye...Petroleum is not a production of direct transformation of organic material into kerogen or oil. Sea organics can’t form such huge oil fields, since these sea creatures will either be consumed by bigger ones or decayed after few days. Farther more these sea animals consist of several components, such as proteins, scales, bones, and minerals, which could not be changed into oil. These should be seen as oil contamination, and we know that oil is relatively <span style="font-family:Verdana;">very pure hydrocarbon. Using methane as a primary component in the</span><span style="font-family:Verdana;"> process of petroleum formation is a logical possibility for several reasons. Methane is quite abundant in nature, since the creation of the globe until these days. Furthermore, methane could be transformed into the different components of the crude oil by polymerization. Methane is highly pure hydrocarbon producing highly pure oil components. Methane could migrate easier than kerogen, and be collected in the methane traps (oil traps), since it behaves like water seeping into the lower beds. By mild heat and pressure at the depth methane polymers (oil components) will be formed. Oil is considered to be formed <i></i></span><i><i><span style="font-family:Verdana;">in-situ</span></i><span style="font-family:Verdana;"></span></i> and not as mentioned in the organic theory, migrating from the kitchen to the oil trap. All the above point of views will be discussing in detail. Alternative ideas which are more logical and more acceptable will be suggested, and it will be the new progress concerning the origin of petroleum, its exploration, and localization.展开更多
The density functional theory（DFT） and self-consistent periodic calculation were used to investigate the C2Hx（x = 4～6） species adsorption on the Fe（110） surface. The adsorption energy and equilibrium geometry o...The density functional theory（DFT） and self-consistent periodic calculation were used to investigate the C2Hx（x = 4～6） species adsorption on the Fe（110） surface. The adsorption energy and equilibrium geometry of the species C2Hx（x = 4～6） on four possible sites（top,hcp,SB and LB） on the Fe（110） surface were predicted and compared. Mulliken charges and density of states analysis of the most stable site have been discussed. It is found that the species of C2H6 and C2H5 are adsorbed strongly on the Fe（110） surface with calculated adsorption energy of -80.24 and -178.89 kJ·mol^-1 at the Fe-LB（long-bridge） ,respectively. However,the C2H4 is adsorbed strongly on the Fe（110） surface with calculated adsorption energies of -114.96 kJ·mol^-1 at the top. The results indicate that the charge transferring process can be completed by chemisorption between Fe（110） surface and the species. Moreover,the chemical bands can be formed by chemisorptions between the Fe（110） surface and the species,too.展开更多
The relationship between chemical structures and photodegradation activity of 12 PAHs is studied using DFT and HF methods, and stepwise multiple linear regression analysis method. The equilibrium geometries and vibrat...The relationship between chemical structures and photodegradation activity of 12 PAHs is studied using DFT and HF methods, and stepwise multiple linear regression analysis method. The equilibrium geometries and vibration frequency have been investigated by considering Solvent effects using a selfconsistent reaction field based on the polarizable continuum model. With DFT and HF methods, different quantum chemical structural descriptors are obtained by quantum chemical calculation and the results with DFT method are better for QSAR model. It is concluded that the photodegradation activity is closely related to its molecular structure. In the regression analysis, the main factors affecting photodegradation rate include the energy of the highest occupied orbital EHOMO and the number of six-carbon benzene ring N1, and the QSAR model successfully established is logkb = 6.046 + 54.830EHOMO + 0.272N1. Statistical evaluation of the developed QSAR shows that the relationships are statistically significant and the model has good predictive ability. EHOMO is the most important factor influcing the photodegradation of PAHs, because the higher EHOMO is, the more easily electron will be excited and the more easily molecular will be degraded. Comparison of the photodegradation of PAHs with their biodegradation shows that the committed step of biodegradation is that the effects of microorganisms make the chemical bond break, while in the committed step of photodegradation PAHs eject electrons.展开更多
This paper expounds the basic principles and structures of the whole petroleum system to reveal the pattern of conventional oil/gas-tight oil/gas-shale oil/gas sequential accumulation and the hydrocarbon accumulation ...This paper expounds the basic principles and structures of the whole petroleum system to reveal the pattern of conventional oil/gas-tight oil/gas-shale oil/gas sequential accumulation and the hydrocarbon accumulation models and mechanisms of the whole petroleum system.It delineates the geological model,flow model,and production mechanism of shale and tight reservoirs,and proposes future research orientations.The main structure of the whole petroleum system includes three fluid dynamic fields,three types of oil and gas reservoirs/resources,and two types of reservoir-forming processes.Conventional oil/gas,tight oil/gas,and shale oil/gas are orderly in generation time and spatial distribution,and sequentially rational in genetic mechanism,showing the pattern of sequential accumulation.The whole petroleum system involves two categories of hydrocarbon accumulation models:hydrocarbon accumulation in the detrital basin and hydrocarbon accumulation in the carbonate basin/formation.The accumulation of unconventional oil/gas is self-containment,which is microscopically driven by the intermolecular force(van der Waals force).The unconventional oil/gas production has proved that the geological model,flow model,and production mechanism of shale and tight reservoirs represent a new and complex field that needs further study.Shale oil/gas must be the most important resource replacement for oil and gas resources of China.Future research efforts include:(1)the characteristics of the whole petroleum system in carbonate basins and the source-reservoir coupling patterns in the evolution of composite basins;(2)flow mechanisms in migration,accumulation,and production of shale oil/gas and tight oil/gas;(3)geological characteristics and enrichment of deep and ultra-deep shale oil/gas,tight oil/gas and coalbed methane;(4)resource evaluation and new generation of basin simulation technology of the whole petroleum system;(5)research on earth system-earth organic rock and fossil fuel system-whole petroleum system.展开更多
基金supported by the National High Technology Research and Development Program of China(2009AA044701)the Program for Zhejiang Leading Team of S&T Innovation(2013TD07)
文摘To get deep understanding of the reaction mechanism of coal pyrolysis in hydrogen plasma, the decomposition reaction pathways of aliphatic hydrocarbons and cycloalkanes, which are two main components in volatiles from coal, were investigated. Methane and cyclohexane were chosen as the model compounds. Density functional theory was employed, and many reaction pathways were involved. Calculations were carried out in Gaussian 09 at the B3LYP/6-31G（d,p） level of the theory. The results indicate that the main pyrolysis products of methane and cyclohexane in hydrogen plasma are both hydrogen and acetylene, and the participation of active hydrogen atoms makes dehydrogenation reactions more favorable. H2 mainly comes from dehydrogenation process, while many reaction pathways are responsible for acetylene formation. During coal pyrolysis in hydrogen plasma, three main components in volatiles like aliphatic hydrocarbons, cycloalkanes and aromatic hydrocarbons lead to the formation of hydrogen and acetylene, but their contributions to products distribution are different.
文摘Quantitative representation of complicated behavior of fluid mixtures in the critical region by any of equation-of-state theories re-mains as a difficult thermodynamic topics to date. In the present work, a computational efforts were made for representing various types of critical loci of binary water with hydrocarbon systems showing Type II and Type III phase behavior by an elementary equation of state [called multi-fluid nonrandom lattice fluid EOS (MF-NLF EOS)] based on the lattice statistical mechanical theory. The model EOS requires two mo-lecular parameters which representing molecular size and interaction energy for a pure component and single adjustable interaction energy pa-rameter for binary mixtures. Critical temperature and pressure data were used to obtain molecular size parameter and vapor pressure data were used to obtain interaction energy parameter. The MF-NLF EOS model adapted in the present study correlated quantitatively well the critical loci of various binary water with hydrocarbon systems.
基金Supported by the Petro China Science and Technology Project(2023YQX10101)National Natural Science Foundation of China(42372165)。
文摘Based on the research progress of the geological theory of coal-formed gas,the contributions of coal-formed gas to the natural gas reserves and production in China and to the development of natural gas in major gas-producing basins are analyzed,and the key favorable exploration zones for coal-formed gas in China are comprehensively evaluated.The following results are obtained.First,coal measures are good gas source rocks,and hydrocarbon generation from coal measure was dominated by gas,followed by oil.Second,a natural gas genetic identification index system based on stable isotopes,light hydrocarbon components,and biomarkers is established.Third,the quantitative and semi-quantitative factors controlling the formation of large gas fields,represented by the indicator of gas generation intensity greater than 20×10^(8) m^(3)/km^(2),are identified to guide the discovery of large gas fields in China.Fourth,coal-formed gas is the major contributor to the current natural gas reserves and production of China,both accounting for over 55%.The high proportion of coal-formed gas has enabled the Tarim,Sichuan and Ordos basins to be the major gas production areas in China.Fifth,coal rock gas is an important field for future exploration of coal-formed gas,and key zones include the Carboniferous Benxi Formation(Fm.)in the Wushenqi-Mizhi area of the Ordos Basin,the Permian Longtan Fm.in central-southern Sichuan Basin,the Jurassic Xishanyao Fm.in the southern margin and Luliang uplift of the Junggar Basin.Sixth,tight gas is the main area for increasing reserves and production,and the favorable exploration zones include the Carboniferous-Permian in southern Ordos Basin and the Bohai Bay Basin,and the Triassic Xujiahe Fm.in the transition zone between central and western Sichuan Basin.Seventh,the Jurassic in the southern margin of the Junggar Basin is a key favorable exploration zone for subsequent investigation of conventional coal-formed gas.These insights have valuable theoretical and practical significance for further developing and improving the theory of coal-formed gas,and guiding the exploration of coal-formed gas fields in China.
基金supported by the National Natural Science Foundation of China(21446003)the Specialized Research Fund for the Doctoral Program of Higher Education(20130074110018)~~
文摘Periodic density functional theory was applied to investigate the reaction mechanism for the methylation of toluene with methanol over HZSM-5.The results indicated that toluene could be methylated at its para,meta,ortho and geminal positions via a concerted or stepwise pathway.For the concerted pathway,the calculated free energy barriers for the para,meta,ortho and geminal methylation reactions were 167,138,139 and 183 kJ/mol,respectively.For the stepwise pathway,the dehydration of methanol was found to be the rate-determining step with a free energy barrier of145 kj/mol,whereas the free energy barriers for the methylation of toluene at its para,meta,ortho and geminal positions were 127,105,106 and 114 kj/mol,respectively.Both pathways led to the formation of C8H11^＋ species as important intermediates,which could back-donate a proton to the zeolite framework via a reorientation process or form gaseous products through demethylation.Methane was formed via an intramolecular hydrogen transfer reaction from a ring carbon of the C8H11^＋ species to the carbon of the methyl group,with calculated energy barriers of 136,132 and134 kj/mol for the para,meta and ortho C8H11^＋ species,respectively.The calculated free energy barriers for the formation of para-,meta- and ortho-xylene indicated that the formation of the para-xylene had the highest energy barrier for both pathways.
文摘Investigation of spatial distribution of oil and gas resource and accurate prediction of the geographic location of its undiscovered resource is significant for reducing exploration risk and improving exploration benefit.A new method for predicting spatial distribution of oil resource is discussed in this paper.It consists of prediction of risk probability in petroleum exploration and simulation of hydrocarbon abundance. Exploration risk probability is predicted by multivariate statistics,fuzzy mathematics and information processing techniques.A spatial attribute database for sample wells was set up and the Mahalanobis distance and Fuzzy value of given samples were obtained.Then,the Bayesian formula was used to calculate the hydrocarbon-bearing probability at the area of exploration wells.Finally,a hydrocarbon probability template is formed and used to forecast the probability of the unknown area. The hydrocarbon abundance is simulated based on Fourier integrals,frequency spectrum synthesis and fractal theory.Firstly,the fast Fourier transformation（FFT） is used to transform the known hydrocarbon abundance from the spatial domain to the frequency domain,then,frequency spectrum synthesis is used to produce the fractal frequency spectrum,and FFT is applied to get the phase information of hydrocarbon-bearing probability.Finally,the frequency spectrum simulation is used to calculate the renewed hydrocarbon abundance in the play. This method is used to predict the abundance and possible locations of the undiscovered petroleum accumulations in the Nanpu Sag of the Bohai Bay Basin,China.The prediction results for the well-explored onshore area of the northern Nanpu Sag agree well with the actual situations.For the less-explored offshore areas in the southern Nanpu Sag,the prediction results suggest high hydrocarbon abundance in Nanpu-1 and Nanpu-2,providing a useful guiding for future exploration.
基金supported by the National Natural Science Foundation Project(Grant No.41102085)the National Key Basic Research and Development 973 Program Project(Grant No.2011CB201105)+1 种基金Supported by Research Fund for the Doctoral Program of Higher Education of China(20110007120001)Supported by Science Foundation of China University of Petroleum, Beijing(No.KYJJ2012-01-08)
文摘Hydrocarbon source rock obviously controls the formation and distribution of hydrocarbon reservoirs. Based on the geological concept of ＂source control theory＂, the concept of a hydrocarbon distribution threshold was put forward. This means the maximum range for hydrocarbon controlled by the source rock conditions to migrate in the hydrocarbon basins. Three quantitative analysis models are proposed on this basis, namely the hydrocarbon accumulation probability, maximum hydrocarbon scale threshold and reserve distribution probability, which respectively refer to the probability of forming a hydrocarbon reservoir, the possible maximum scale of the hydrocarbon reservoir and the percentage of reserve distribution in a certain area within the hydrocarbon distribution threshold. Statistical analysis on 539 hydrocarbon reservoirs discovered in 28 hydrocarbon source kitchens from seven sedimentary basins and sags of eastern China shows the maximum reservoir scale possibly formed in the hydrocarbon basin, hydrocarbon accumulation probability and oil and gas reserve distribution probability are all controlled by the characteristics of the hydrocarbon source rock. Generally, as the distances from the hydrocarbon source rock center and hydrocarbon discharge boundary get longer and the hydrocarbon discharge intensity of hydrocarbon source rock center gets smaller, there will be lower probability of hydrocarbon accumulation. Corresponding quantitative models are established based on single factor statistics and multivariate analysis. Practical application in the Jiyang Depression shows that the prediction from the quantitative analysis model for the hydrocarbon distribution threshold agree well with the actual exploration results, indicating that the quantitative analysis model is likely to be a feasible tool.
基金supported by the National Natural Science Foundation of China (No. 40976041,20775074)
文摘The relationship between chemical structures and biodegradation rates （k b） of 22 polycyclic aromatic hydrocarbons （PAHs） was studied using density functional theory （DFT） and stepwise multiple linear regression analysis （SMLR） method.The equilibrium geometries and vibration frequency have been investigated at the B3LYP/6-31＋G（d,p） level by thinking Solvent effects using a selfconsistent reaction field （SCRF） based on the polarizable continuum model （PCM）.It was concluded that the biodegradation rate was closely related to its molecular structure,and there is one high correlation coefficient between the in-plane bending vibration frequency of the conjugated ring of PAHs （Freq） and k b.By means of regression analysis,the main factors affecting the biodegradation rate were obtained and the equation of quantitative structure-activity relationship （QSAR） was successfully established kb =-0.653＋0.001Freq＋0.068CQ＋0.049N1.Statistical evaluation of the developed QSAR showed that the relationships were statistically significant and the model had good predictive ability.The fact that a bending frequency is more important than the HOMO or LUMO energies in predicting k b suggests that the bending of benzene ring might play an important role in the enzymatic catalysis of the initial oxidation step.
文摘Speed of sound data for butyl acetate＋benzene, or toluene, or o-xylene, or m-xylene, or p-xylene binary mixtures have been measured over the entire range of mole fraction at 308.15 K. The excess isentropic compressibilities （ Ks^E ） were computed from speed of sound and density data, derived from molar excess volume data. The Ks^E values were analyzed by using graph theoretical approach. The Ks^E values evaluated by graph theory compared reasonably well with their corresponding experimental values. The Ks^E data were also expressed in terms of Redlich-Kister polynomial equation to derive the coefficients and the standard deviation.
文摘The C--C bond dissociation energy （BDE） is a very important data in research of hydrocarbon cracking reactions, because it reflects the difficulty level of chemical reactions. But it is very difficult to obtain the C--C bond dissociation energy （BDE） by experiments, so using quantum chemistry calculation such as density functional theory （DFT） to study the C--C bond dissociation energy is a very useful means. The impact of acceptor substituents and donor substituents on the C--C bond length distribution was studied.
文摘Petroleum is not a production of direct transformation of organic material into kerogen or oil. Sea organics can’t form such huge oil fields, since these sea creatures will either be consumed by bigger ones or decayed after few days. Farther more these sea animals consist of several components, such as proteins, scales, bones, and minerals, which could not be changed into oil. These should be seen as oil contamination, and we know that oil is relatively <span style="font-family:Verdana;">very pure hydrocarbon. Using methane as a primary component in the</span><span style="font-family:Verdana;"> process of petroleum formation is a logical possibility for several reasons. Methane is quite abundant in nature, since the creation of the globe until these days. Furthermore, methane could be transformed into the different components of the crude oil by polymerization. Methane is highly pure hydrocarbon producing highly pure oil components. Methane could migrate easier than kerogen, and be collected in the methane traps (oil traps), since it behaves like water seeping into the lower beds. By mild heat and pressure at the depth methane polymers (oil components) will be formed. Oil is considered to be formed <i></i></span><i><i><span style="font-family:Verdana;">in-situ</span></i><span style="font-family:Verdana;"></span></i> and not as mentioned in the organic theory, migrating from the kitchen to the oil trap. All the above point of views will be discussing in detail. Alternative ideas which are more logical and more acceptable will be suggested, and it will be the new progress concerning the origin of petroleum, its exploration, and localization.
基金Project supported by the Natural Science Foundation of Education Committee of Chongqing (No. KJ091311)
文摘The density functional theory（DFT） and self-consistent periodic calculation were used to investigate the C2Hx（x = 4～6） species adsorption on the Fe（110） surface. The adsorption energy and equilibrium geometry of the species C2Hx（x = 4～6） on four possible sites（top,hcp,SB and LB） on the Fe（110） surface were predicted and compared. Mulliken charges and density of states analysis of the most stable site have been discussed. It is found that the species of C2H6 and C2H5 are adsorbed strongly on the Fe（110） surface with calculated adsorption energy of -80.24 and -178.89 kJ·mol^-1 at the Fe-LB（long-bridge） ,respectively. However,the C2H4 is adsorbed strongly on the Fe（110） surface with calculated adsorption energies of -114.96 kJ·mol^-1 at the top. The results indicate that the charge transferring process can be completed by chemisorption between Fe（110） surface and the species. Moreover,the chemical bands can be formed by chemisorptions between the Fe（110） surface and the species,too.
基金supported by the National Natural Science Foundation of China(Nos.40976041 and 20775074)
文摘The relationship between chemical structures and photodegradation activity of 12 PAHs is studied using DFT and HF methods, and stepwise multiple linear regression analysis method. The equilibrium geometries and vibration frequency have been investigated by considering Solvent effects using a selfconsistent reaction field based on the polarizable continuum model. With DFT and HF methods, different quantum chemical structural descriptors are obtained by quantum chemical calculation and the results with DFT method are better for QSAR model. It is concluded that the photodegradation activity is closely related to its molecular structure. In the regression analysis, the main factors affecting photodegradation rate include the energy of the highest occupied orbital EHOMO and the number of six-carbon benzene ring N1, and the QSAR model successfully established is logkb = 6.046 + 54.830EHOMO + 0.272N1. Statistical evaluation of the developed QSAR shows that the relationships are statistically significant and the model has good predictive ability. EHOMO is the most important factor influcing the photodegradation of PAHs, because the higher EHOMO is, the more easily electron will be excited and the more easily molecular will be degraded. Comparison of the photodegradation of PAHs with their biodegradation shows that the committed step of biodegradation is that the effects of microorganisms make the chemical bond break, while in the committed step of photodegradation PAHs eject electrons.
基金Supported by the National Natural Science Foundation of China(U22B6002)PetroChina Science Research and Technology Development Project(2021DJ0101)。
文摘This paper expounds the basic principles and structures of the whole petroleum system to reveal the pattern of conventional oil/gas-tight oil/gas-shale oil/gas sequential accumulation and the hydrocarbon accumulation models and mechanisms of the whole petroleum system.It delineates the geological model,flow model,and production mechanism of shale and tight reservoirs,and proposes future research orientations.The main structure of the whole petroleum system includes three fluid dynamic fields,three types of oil and gas reservoirs/resources,and two types of reservoir-forming processes.Conventional oil/gas,tight oil/gas,and shale oil/gas are orderly in generation time and spatial distribution,and sequentially rational in genetic mechanism,showing the pattern of sequential accumulation.The whole petroleum system involves two categories of hydrocarbon accumulation models:hydrocarbon accumulation in the detrital basin and hydrocarbon accumulation in the carbonate basin/formation.The accumulation of unconventional oil/gas is self-containment,which is microscopically driven by the intermolecular force(van der Waals force).The unconventional oil/gas production has proved that the geological model,flow model,and production mechanism of shale and tight reservoirs represent a new and complex field that needs further study.Shale oil/gas must be the most important resource replacement for oil and gas resources of China.Future research efforts include:(1)the characteristics of the whole petroleum system in carbonate basins and the source-reservoir coupling patterns in the evolution of composite basins;(2)flow mechanisms in migration,accumulation,and production of shale oil/gas and tight oil/gas;(3)geological characteristics and enrichment of deep and ultra-deep shale oil/gas,tight oil/gas and coalbed methane;(4)resource evaluation and new generation of basin simulation technology of the whole petroleum system;(5)research on earth system-earth organic rock and fossil fuel system-whole petroleum system.
