The resource of the gas from coal and coal measures deep in Songliao Basin has been drawing more and more attention to . It is necessary to find out the evolution regularity of the geothermal field of the basin in add...The resource of the gas from coal and coal measures deep in Songliao Basin has been drawing more and more attention to . It is necessary to find out the evolution regularity of the geothermal field of the basin in addition to a series of geological studies in order to predict its resources because the ancient geothermal field of the basin is one of the main factors controlling the generation , evolution and disappearance of oil and gas . In the recent twenty years , it is generally believed that vitrinite reflectance is the best quantitative marker for the ancient geothermal field . In the present paper , a systematic study of the vitrinite reflectance value of Songliao Basin and its influence factors is made by multiple statistical analysis so as to reconstruct the evolutional process of the Moho and the corresponding geothermal field . Then , an overall prediction is made of the vitrinite reflectance and the distribution of J3-K1 fault basin group at the bottom of Songliao Basin , which provides the evidence for the further prediction of the gas potentiality from coal and coal measures deep in the basin .展开更多
The law of mathematical statistics, which the coal vitrinite reflectance index obeys, the existing vitrinite representing deviations, and the advantages of judging coalification and the shortage of judging coal type w...The law of mathematical statistics, which the coal vitrinite reflectance index obeys, the existing vitrinite representing deviations, and the advantages of judging coalification and the shortage of judging coal type were analyzed. The advantages and disadvantages of various determination methods and the expression index and different methods of identifying vitrinite on the determination results were compared. The vitality of coal vitrinite reflectance depends on its full play the unique function of reflectance histogram and the systematic errors between different determination methods do not affect the application based on reflectance histogram are considered.展开更多
The product distribution and kinetic analysis of low-rank coal vitrinite were investigated during the chemical looping gasification(CLG)process.The acid washing method was used to treat low-rank coal,and the density g...The product distribution and kinetic analysis of low-rank coal vitrinite were investigated during the chemical looping gasification(CLG)process.The acid washing method was used to treat low-rank coal,and the density gradient centrifugation method was adopted to obtain the coal macerals.By combining thermogravimetric analysis and online mass spectrometry,the influence of the heating rate and oxygen carrier(Fe2O3)blending ratio on product distribution was discussed.The macroscopic kinetic parameters were solved by the Kissinger-Akahira-Sunose(KAS)method,and the main gaseous product formation kinetic parameters were solved by the iso-conversion method.The results of vitrinite during slow heating chemical looping gasification showed that the main weight loss interval was 400–600℃,and the solid yield of sample vitrinite-Fe-10 at different heating rates was 64.30%–69.67%.When b=20℃·min^(-1),the maximum decomposition rate of vitrinite-Fe-10 was 0.312%min1.The addition of Fe2O_(3)reduced the maximum decomposition rate,but by comparing the chemical looping conversion characteristic index,it could be inferred that the chemical looping gasification of vitrinite might produce volatile substances higher than the pyrolysis process of vitrinite alone.The average activation energy of the reaction was significantly reduced during chemical looping gasification of vitrinite,which was lower than the average activation energy of 448.69 kJ·mol^(-1) during the pyrolysis process of vitrinite alone.The gaseous products were mainly CO and CO_(2).When the heating rate was 10℃·min^(-1),the highest activation energy for CH4 formation was 21.353 kJ·mol^(-1),and the lowest activation energy for CO formation was 9.7333 kJ·mol^(-1).This study provides basic data for exploring coal chemical looping gasification mechanism and reactor design by studying the chemical looping gasification process of coal macerals。展开更多
Thermal maturity is commonly assessed by various geochemical screening methods(e.g.,pyrolysis and organic petrology).In this contribution,we attempt to establish an alternative approach to estimating thermal maturity ...Thermal maturity is commonly assessed by various geochemical screening methods(e.g.,pyrolysis and organic petrology).In this contribution,we attempt to establish an alternative approach to estimating thermal maturity with Raman spectroscopy,using 24 North American oil shale samples with thermal maturity data generated by vitrinite reflectance(VRo%)and pyrolysis(Tmax)-based maturity calculation(VRe%).The representative shale samples are from the Haynesville(East Texas),Woodford(West Texas),Eagle Ford and Pearsall(South Texas)Formations,as well as Gothic,Mancos,and Niobrara Formation shales(all from Colorado).The Raman spectra of disordered carbonaceous matter(D1 and G bands separation)of these samples were directly obtained from the rock chips without prior sample preparation.Using the Gaussian and Lorentzian distribution approach,thermal maturities from VR were correlated with carbon G and D1.We found that the Raman band separation(RBS)displayed a better correlation for equivalent VRe%than vitrinite reflectance VRo%.The RBS(D1–G)distance versus total organic carbon,free hydrocarbons from thermal extraction(S1),and the remaining hydrocarbon generating potential(S2)indicate that the RBS(D1–G)distance is also related to kerogen type.Data presented here from three methods of maturity determination of shale demonstrate that Raman spectroscopy is a quick and valid approach to thermal maturity assessment.展开更多
Reconstructing the thermal evolution of the eastern Qaidam Basin is important for gaining a deeper understanding of its lithospheric geodynamics and for more accurate hydrocarbon evaluation and prediction.This article...Reconstructing the thermal evolution of the eastern Qaidam Basin is important for gaining a deeper understanding of its lithospheric geodynamics and for more accurate hydrocarbon evaluation and prediction.This article presents a set of new apatite and zircon(U-Th)/He thermochronological ages.Combined with 336 vitrinite reflectance(R_(o))data,the thermal history of the Ouanan Sag in the eastern Qaidam Basin has been reconstructed using inversion models.Three detrital samples from the Ounan Sag shows that the apatite(U-Th)/He ages are primarily concentrated in the range of 17.0 Ma to 76.5 Ma and that the zircon(U-Th)/He ages range from 200 Ma to 289.3 Ma.The time-temperature models demonstrate that the Ounan Sag experienced rapid subsidence and heating from the Carboniferous to late Permian,and exhumation/cooling events from the end of Permian to the Triassic.This thermal evolution was influenced by the widespread intrusion of plutons,and the collision and orogenesis caused by asthenosphere upwelling below the Qaidam arc,and slab rollback of the Southern Kunlun oceanic lithosphere,respectively.Additionally,our models depict the main exhumation/cooling stages since the Paleogene and a reheating event in the Miocene as a result of the intensifying growth of the Qinghai-Tibet Plateau and local sedimentary loading,followed by the initial India-Eurasia collision.Furthermore,the eastern Qaidam Basin experienced consistent heating during the late Paleozoic,reaching the maximum paleotemperature and geothermal gradient in the late Permian,with values of~230℃and~43-44℃/km,respectively.This study suggests that the source rocks in the most upper member of upper Carboniferous Keluke(C_(2)k)Formations in the Ounan Sag reached the gas generation stage in the late Permian.展开更多
Based on the models developed by Lerche et al. (1984) and Pang et al. (1993), an improved model for calculating paleoheat flow into basins is investigated. The new model is an optimization problem with the state varia...Based on the models developed by Lerche et al. (1984) and Pang et al. (1993), an improved model for calculating paleoheat flow into basins is investigated. The new model is an optimization problem with the state variables governed by a thermal conduction equation. A genetic algorithm is used to solve the highly nonlinear optimization problem. As an application, the model is applied to the research into the history of heat flow in the Pearl River Mouth basin located in the South China Sea. The numerical analysis shows that the simulation results are in good agreement with the measured data and indicates that the basin may have undergone three rifting and thermal events. It is also demonstrated that a high R0 gradient reflects a response to high paleoheat flow during the early, rapid subsidence stage, while a low R0 gradient is a result of the thermal decay during the thermal subsidence because of thermal contraction of a cooling lithosphere.展开更多
Three typical vitrinite reflectance (R0) proriles from Pearl River Mouth, Qiongdongnan and Beibuwan basins on the nortbern condsental shelf or the South China Sea display two or more different sub-linear slope relatio...Three typical vitrinite reflectance (R0) proriles from Pearl River Mouth, Qiongdongnan and Beibuwan basins on the nortbern condsental shelf or the South China Sea display two or more different sub-linear slope relationships between IgR0 and deptb. According to the reconstruction of sedimentary and burial histories for these wells, a relatively large R0 gradient corresponds to a high depositional rate, while a relatively small R0 gradieut represeuts a low depositional rate. In this study, a modiried thermal backstripping model for paleokeat fIow using vitrinite reflectance data has been used to reconstruct paleotbermal history by the linear-segmeut regression. Tke study results indicate that the gentle parts of a IgR0 profile rerlect abnormai periods or high paleoheat flow, in contrast, the steep parts of a IgR0 profile reflect periods of peleoheat flow decay.In order to have an alternative approach and correlative study, an improved two-layer extensional model for the formation and evolution or rifting basin iu pesive contiueutal margin bas been applied. The model simulates basin subsidence process due to stretcbing and thinuing of continental lithospbere and thermal effects by asthenospbere upwelling, and determines the relationship between subsidence and paleoheat flux through the geological time. The simulation results suggest that these basins have undergone two or three rirting and thermal events, and it is clear that the large R0 gradient segment reflects a response to high paleoheat flow during the early, rapid subsidence stage, while the low R. gradient segmeut is a result or the tbermal decay during the thermal subsidence because of thermal contraction of a cooling Iitbospbere. The results also suggest that the maturity profiles of these basins can be employed to visual understanding tke paleogeothermal characteristics of rifting basins.展开更多
Based on the Arrhenius equation and Karweil method, a simulation calculation has been made on the thermal maturation of organic matter under a series of assuming paleotem-perature gradients. Results show that there wa...Based on the Arrhenius equation and Karweil method, a simulation calculation has been made on the thermal maturation of organic matter under a series of assuming paleotem-perature gradients. Results show that there was a positive correlation of vitrinite reflectance gradient with paleotemperature gradient and vitrinite reflectance. According to this, a model展开更多
The humilith series of lignite,longflame coal,gas coal,fat coal,coking coal,lean coal,meagre coal and anthracite are measured by FIR1600 infrared spectrophotometer.The variation curve between the infrared absorption w...The humilith series of lignite,longflame coal,gas coal,fat coal,coking coal,lean coal,meagre coal and anthracite are measured by FIR1600 infrared spectrophotometer.The variation curve between the infrared absorption wave number of aromaticring C--C bond of vitrinite and its reflectance values are gained,which shows the shift of infrared absorption wave number of aromaticring C--C bond of humic coals towards lower wave number with the increase of coalification.It is believed that the coal rank of humilith series can be determined and more evolutional information about coal composition and structure can be obtained by the infrared spectroscopic method.展开更多
Kinetics study of gaseous hydrocarbons generated from vitrinites based on pyrolysis of gold tube closed system shows that the activation energies of methane generated from telocollinite are higher than that from desmo...Kinetics study of gaseous hydrocarbons generated from vitrinites based on pyrolysis of gold tube closed system shows that the activation energies of methane generated from telocollinite are higher than that from desmocol-linite due to structure differences. But carbon isotope ratios of generated methane in pyrolysates of vitrinites at the same temperature points are similar. Carbon isotope ratio of methane may decrease in the early stage of gas generation and then increase in the later stage. But at higher temperature, δ13C1 decreases slightly or almost keeps stable with increasing temperature. Since it is known that carbon isotope distillation is controlled by time, temperature and carbon isotope ratio of bulk organic matter, the character of side chains connected to macromolecule of vitrinite and distribution of activation energies have no obvious effect on carbon isotope fraction. Decreasing trend of δ13C1 in the early stage may be caused by contagious structure of vitrinite or differences of展开更多
The absence of humic vitrinite complicates the determination of thermal maturity in pre-Devonian sediments.Lower Paleozoic shales contain structured zooclasts,solid bitumen,and vitrinite-like materials,and their refle...The absence of humic vitrinite complicates the determination of thermal maturity in pre-Devonian sediments.Lower Paleozoic shales contain structured zooclasts,solid bitumen,and vitrinite-like materials,and their reflectances have been found to be valid maturity proxies.Yet there remains much controversy as to the degree of evolution of reflectances.The current work aims to investigate the reflectance of dispersed organic matter(DOM),as well as their transformation degree and organic pore development.To this end,this study evaluated an Upper Ordovician zooclasts-bearing shale and a Middle Jurassic coal sample via anhydrous-pyrolysis to compare differences in the maturation pathways between marine-derived DOM and terrigenous vitrinite.These two original samples were cut into small blocks and placed in an identical vacuum stainless vessel simultaneously.The pyrolysis was carried out at isothermal temperatures ranging from 250 to 550℃ for 48 h.The morphologic and reflectance changes of DOM in pyrolysis residues were studied and compared with previous pyrolysis results.Adopting the combined use of optical reflectance and scanning electron microscope(SEM)techniques,the study shows that DOM in the shale components consists of solid bitumen(SB),bituminite,chitinozoans,a few graptolites,vitrinite-like particles(VLP),alginate and liptodetrinite.The reflectance sequence,from high to low,is zooclasts,VLP and SB.Their reflectances gradually increases as the pyrolysis temperature rises,although the rate of growth is slower than that of co-heating coal vitrinite.Notably,zooclasts yield significantly higher reflectance values than those of VLP and SB at each pyrolysis temperature.However,the VLP undergoes two distinct phases in reflectance development,despite gradual morphology changes similar to vitrinite.Based on evidence of the optical texture and organic pore evolution,we argue that a fair amount of VLP in studied Upper Ordovician shale does not consist of graptolite-type fragments.Consequently,the VLPRo serves as a reliable indicator for assessing organic matter maturity in Ordovician shales with a reflectance value of less than 2.0%.This investigation enhances scholarly understandings of marine-derived DOM evolution issues,providing clearer correlations among reflectances of different DOM and reducing uncertainties in thermal maturity determination.展开更多
The paper contains the results of investigation of interconnections between coals’vitrinite structural features,mode of its crushing under the cyclic nanoindentation with increasing peak load and coals’proneness to ...The paper contains the results of investigation of interconnections between coals’vitrinite structural features,mode of its crushing under the cyclic nanoindentation with increasing peak load and coals’proneness to formation of airborne respirable dust(ARD)with particles sized<10μm(PM10).A specific value of PM10 contents in coals normalized on a fines fraction(with particles sizes of less than 200μm)was used as a measure of proneness to ARD formation.It has been shown that the aforementioned parameter is predefined by the ratio of amorphous and crystalline carbon compounds in vitrinite and the mode of its crushing.Some preliminary investigation have been done in order to characterize the involvement of inertinite in ARD formation.It was proposed that the inertinite is not as actively involved in the processes of ARD formation of coals as vitrinite,having a more diverse structural features in terms of amorphous to crystalline carbon compounds ratio.展开更多
This study comprises the relationship between organic matter(OM)and gold occurrence using two distinctive ore deposits of the Bakyrchik gold-sulfide deposit(Kazakhstan)and Western Mecsek uranium ore deposit(Hungary).T...This study comprises the relationship between organic matter(OM)and gold occurrence using two distinctive ore deposits of the Bakyrchik gold-sulfide deposit(Kazakhstan)and Western Mecsek uranium ore deposit(Hungary).The two ore deposits are identified as organicrich sedimentary formations linked to the Variscan gold cycle globally.Characterizing OM is essential because it can act as a carrier for gold,influencing its distribution and behavior within the deposit.Understanding the nature and distribution of OM can provide insights into the processes of gold deposition and help optimize exploration and extraction strategies in mining operations.The primary objective is to characterize OM by identifying its elemental composition,thermal maturity,functional groups,and soluble fractions;and extract gold from OM using a two-step sequential extraction method(hydrogen peroxide and aqua regia)combined with geochemical techniques.Analytical and experimental results from samples of both ore deposits indicate the presence of finely disseminated solid bitumen and reworked vitrinite,originating from thermally matured(RmcRo%—3.76 in Bakyrchik;Ro%—2.25 in W-Mecsek)terrigenous high plants.Both deposits exhibit extremely low extractable bitumen yield and TOC(0.34%in Bakyrchik;0.25 wt%in W-Mecsek),characterized by an aromatic carboxylic acid organic structure and a composition rich in sulfur-containing(1.17%in Bakyrchik;5.81%in W-Mecsek)aromatic hydrocarbons.Gold occurrence and enrichment within OM were confi rmed through the sequential extraction method employing ICP-OES and LA-ICP-MS techniques.The sequentially extracted gold content from OM reached up to 3 ppm in Bakyrchik and up to 3.28 ppm in Western Mecsek,accompanied by Ag(ranging from 0.01 to 0.32 ppm).Higher concentrations of Au(4 ppm)and Ag(27 ppm)were extracted from residue materials,which are likely associated with sulfide minerals.The presence of gold in OM was further validated using LA-ICP-MS.Gold bonding within OM structure,gold is preserved in the form of lattice gold or structurally bonded metal most likely within the aromatic hydrocarbon fractions of the OM in both the W-Mecsek and Bakyrchik deposits.These findings underscore the profound potential of ongoing exploration endeavors,off ering pivotal revelations regarding the extraction and practical application of Au and Ag derived from OM within the geochemical framework of both ore deposits.展开更多
The thermal history of sedimentary basins is a key factor for hydrocarbon accumulation and resource assessment, and is critical in the exploration of lithospheric tectono-thermal evolution. In this paper, the Cenozoic...The thermal history of sedimentary basins is a key factor for hydrocarbon accumulation and resource assessment, and is critical in the exploration of lithospheric tectono-thermal evolution. In this paper, the Cenozoic thermal histories of nearly 200 wells and the Mesozoic thermal histories of 15 wells are modeled based on the vitrinite reflectance and apatite fission track data in Bohai Bay Basin, North China. The results show that the basin experienced Early Cretaceous and Paleogene heat flow peaks, which reveals two strong rift tectonic movements that occurred in the Cretaceous and the Paleogene in the basin, respectively. The thermal evolution history in Bohai Bay Basin can be divided into five stages including（1） the low and stable heat flow stage from the Triassic to the Jurassic, with the heat flow of 53 to 58 m W/m2;（2） the first heat flow peak from the Early Cretaceous to the middle of the Late Cretaceous, with a maximum heat flow of 81 to 87 m W/m2;（3） the first post-rift thermal subsidence stage from the middle of the Late Cretaceous to the Paleocene, with the heat flow of 65 to 74 m W/m2 at the end of the Cretaceous;（4） the second heat flow peak from the Eocene to the Oligocene, with a maximum heat flow of 81 to 88 m W/m2; and（5） the second thermal subsidence stage from the Neogene to present, with an average heat flow of 64 m W/m2.展开更多
In order to study the accumulation mechanism of＂barkinite＂,eight Late Permian channel benches（approximately 15-cm across and 10-cm deep） were taken from the Jinshan Mine,Anhui Province,China.The samples were analy...In order to study the accumulation mechanism of＂barkinite＂,eight Late Permian channel benches（approximately 15-cm across and 10-cm deep） were taken from the Jinshan Mine,Anhui Province,China.The samples were analyzed by microscopical and geochemical methods.The microscopical observations indicate that the occurrence modes of＂barkinite＂in this area are different from those in other areas of China.The ratios of structureless＂barkinite＂are much higher in the Jinshan Mine,probably due to the flow-water and marine influenced environments.Furthermore, vitrinite macerals also show a strong fluorescence.The vitrinite fluorescence characteristics have not been observed in the Permian＂barkinite＂coals from northern China.The composition and variation of minerals in the column section also showed that the swamps in the study area were seriously influenced by seawater in the early and late stage during the peat accumulation.展开更多
Using well logs data only, the evaluation of shale gas hydrocarbon potential of Talhar Shale Member of Lower Goru Formation has been a challenge in Southern Lower Indus Basin in Pakistan. Well logs data analysis is he...Using well logs data only, the evaluation of shale gas hydrocarbon potential of Talhar Shale Member of Lower Goru Formation has been a challenge in Southern Lower Indus Basin in Pakistan. Well logs data analysis is helpful to evaluate the gas potential of source shale rocks. We introduced and applied empirical and graphical method to fulfil this task and derived geochemical parameters from well logs data. The method mentioned is cheap and fast. Talhar Shale has kerogen type Ⅲ and type Ⅱ which are montmorillonite clay and have potential to produce oil and gas. Talhar Shale has better sorption property. Empirical formulas are used to derive parameters, using well logs of porosity, density and uranium. Porosity and volume of kerogen, calculated from density log, give average values of 11.8% and 11.4%. Average value of level of maturity index （LMI） derived from log is 0.54, which indicates that it is at the early stage of maturity. Vitrinite reflectance is between 0.5%-0.55% as calculated by graphical method and empirical formula. Talhar Shale is at onset of oil generation, with main products of oil and gas. It is a good potential source in the study area.展开更多
Coalbed gas （CBG） in Enhong syncline, eastern Yunnan China, is character- ized by high concentration of heavy hydrocarbon with the highest content of ethane, which is more than 30%. Some previous investigators pai...Coalbed gas （CBG） in Enhong syncline, eastern Yunnan China, is character- ized by high concentration of heavy hydrocarbon with the highest content of ethane, which is more than 30%. Some previous investigators paid much attention to the abnormal concentration of heavy hydrocar- bon in the CBG of Enhong, but few have researched on its origin. This article describes the characteristics of abnormal high concentration of heavy hydrocarbon in Enhong syncline and analyzes its reason from the aspects of origin and evolution of heavy hydrocarbon by carbon isotope, coal petrography, and coal rank. Features of gas carbon isotope composition display that there is no inorganic gas or off components in the CBG, which is classified to thermogenetic gas produced by humic material, with characteristic of secondary biogenic gas in shallow coal seam. The concentration of heavy hydrocarbon in Enhong syncline increases with the increase of vitrinite, vitrinite/inertinite ratio, and hydrogen/carbon ratio and decreases with the increase of inertinite, so hydrogen-rich vitrinite may be a very important factor resulting in the abnormal concentration of heavy hydrocarbon. It also increases with the increase of degree of coalifica-tion of coking to lean coals during which the peak of heavy hydrocarbon generation is reached. Therefore, we think that high concentration of heavy hydrocarbon originated from the coupling effect of higher content of the hydrogen-rich vitrinite in the coal and the coal rank of coking to lean coals.展开更多
The thermal history and organic matter maturity evolution of the source rocks of boreholes in the Puguang gas field were reconstructed. An integrated approach based on vitrinite reflectance and apatite fission track d...The thermal history and organic matter maturity evolution of the source rocks of boreholes in the Puguang gas field were reconstructed. An integrated approach based on vitrinite reflectance and apatite fission track data was used in the reconstruction. Accordingly, the geothermal conditions of gas accumulation were discussed in terms of the geological features of reservoirs in the northeastern Sichuan Basin. The strata reached their maximum burial depth in the Late Cretaceous era and were then uplifted and denuded continuously to the present day. The geothermal gradient and heat flow in the Late Cretaceous era were approximately 30.0 °C/km and 66 mW/m2, respectively, which were both higher than those at present. The tectonothermal evolution from the Late Cretaceous era to the present is characterized by denudation and cooling processes with an erosion thickness of2.7 km. In addition to the Triassic era, the Jurassic era represents an important hydrocarbon generation period for both Silurian and Permian source rocks, and the organic matter maturity of these source rocks entered into a dry gas period after oil generation. The thermal conditions are advantageous to the accumulation of conventional and unconventional gas because the hydrocarbon generation process of the source rocks occurs after the formation of an effective reservoir cap. In particular, the high geothermal gradient and increasing temperature before the denudation in the Late Cretaceous era facilitated the generation of hydrocarbons, and the subsequent cooling process favored its storage.展开更多
Thermal maturation and petroleum generation modeling of shales is essential for suc- cessful exploration and exploitation of conventional and unconventional oil and gas plays. For basin- wide unconventional resource p...Thermal maturation and petroleum generation modeling of shales is essential for suc- cessful exploration and exploitation of conventional and unconventional oil and gas plays. For basin- wide unconventional resource plays such modeling, when well calibrated with direct maturity meas- urements from wells, can characterize and locate production sweet spots for oil, wet gas and dry gas. The transformation of kerogen to petroleum is associated with many chemical reactions, but models typically focus on first-order reactions with rates determined by the Arrhenius Equation. A miscon- ception has been perpetuated for many years that accurate thermal maturity modeling of vitrinite re- flectance using the Arrhenius Equation and a single activation energy, to derive a time-temperature index （~TTIARa）, as proposed by Wood （1988）, is flawed. This claim was initially made by Sweeney and Burnham （1990） in promoting their ＂EasyRo＂ method, and repeated by others. This paper dem- onstrates through detailed multi-dimensional burial and thermal modeling and direct comparison of the ~TTIARR and ＂EasyRo＂ methods that this is not the case. The ~TTIA^R method not only provides a very useful and sensitive maturity index, it can reproduce the calculated vitrinite reflectance values derived from models based on multiple activation energies （e.g., ＂EasyRo＂）. Through simple expres- sions the ~TTIAaa method can also provide oil and gas transformation factors that can be flexibly scaled and calibrated to match the oil, wet gas and dry gas generation windows. This is achieved in a more-computationally-efficient, flexible and transparent way by the ~TTIARR method than the ＂EasyRo＂ method. Analysis indicates that the ＂EasyRo＂ method, using twenty activation energies and a constant frequency factor, generates reaction rates and transformation factors that do not realisti- cally model observed kerogen behaviour and transformation factors over geologic time scales.展开更多
The pyrolysis characteristics of Shendong Shangwan coal and its macerals concentrate were investigated using thermogravimetry （TG） coupled with mass spectrometry （MS）. The evolved gases were analyzed online by MS ...The pyrolysis characteristics of Shendong Shangwan coal and its macerals concentrate were investigated using thermogravimetry （TG） coupled with mass spectrometry （MS）. The evolved gases were analyzed online by MS spectroscopy. The results of TG/DTG （derivative thermogravimetry） show ths vitrinite concentrate has greater weight loss rate and higher volatile yield than the other two samples. More light hydrocarbons C1-C5 are released from the vitfinite concentrate than from the Shendong Shangwan coal and inertinite concentrated in the process of pyrolysis. Three samples have similar shape curves of evolved gases of C2~C5 with different intensities. When the pyrolysis temperature was lower than 418℃, the amount of C6H6 evolved in the process of pyrolysis of inertinite concentrated was higher than that of raw coal and vitrinite concentrate. As the temperature rising, the production rate of C6H6 increased. Below 672℃, C6H6 evolution rate of vitrinite concentrate was far greater than the other two samples; the main evolution temperature range of C7H8 was 400℃ to 700℃ for the three samples. The amount of HE and H20 released first increased and then decreased with the temperature increase while more H2 released for pyrolysis of inertinite concentrated and more H20 released for the pyrolysis of vitrinite concentrate.展开更多
文摘The resource of the gas from coal and coal measures deep in Songliao Basin has been drawing more and more attention to . It is necessary to find out the evolution regularity of the geothermal field of the basin in addition to a series of geological studies in order to predict its resources because the ancient geothermal field of the basin is one of the main factors controlling the generation , evolution and disappearance of oil and gas . In the recent twenty years , it is generally believed that vitrinite reflectance is the best quantitative marker for the ancient geothermal field . In the present paper , a systematic study of the vitrinite reflectance value of Songliao Basin and its influence factors is made by multiple statistical analysis so as to reconstruct the evolutional process of the Moho and the corresponding geothermal field . Then , an overall prediction is made of the vitrinite reflectance and the distribution of J3-K1 fault basin group at the bottom of Songliao Basin , which provides the evidence for the further prediction of the gas potentiality from coal and coal measures deep in the basin .
文摘The law of mathematical statistics, which the coal vitrinite reflectance index obeys, the existing vitrinite representing deviations, and the advantages of judging coalification and the shortage of judging coal type were analyzed. The advantages and disadvantages of various determination methods and the expression index and different methods of identifying vitrinite on the determination results were compared. The vitality of coal vitrinite reflectance depends on its full play the unique function of reflectance histogram and the systematic errors between different determination methods do not affect the application based on reflectance histogram are considered.
基金support of the National Natural Science Foundation of China(22038011,51976168)the K.C.Wong Education Foundation,China Postdoctoral Science Foundation(2019M653626)+2 种基金Foundation of State Key Laboratory of High-efficiency Utilization of Coal and Green Chemical Engineering(2020-KF-06)the Promotion Plan for Young People of Shaanxi Association for Science and Technology(20180402)the Technology Foundation for Selected Overseas Chinese Scholar in Shaanxi Province(2018015).
文摘The product distribution and kinetic analysis of low-rank coal vitrinite were investigated during the chemical looping gasification(CLG)process.The acid washing method was used to treat low-rank coal,and the density gradient centrifugation method was adopted to obtain the coal macerals.By combining thermogravimetric analysis and online mass spectrometry,the influence of the heating rate and oxygen carrier(Fe2O3)blending ratio on product distribution was discussed.The macroscopic kinetic parameters were solved by the Kissinger-Akahira-Sunose(KAS)method,and the main gaseous product formation kinetic parameters were solved by the iso-conversion method.The results of vitrinite during slow heating chemical looping gasification showed that the main weight loss interval was 400–600℃,and the solid yield of sample vitrinite-Fe-10 at different heating rates was 64.30%–69.67%.When b=20℃·min^(-1),the maximum decomposition rate of vitrinite-Fe-10 was 0.312%min1.The addition of Fe2O_(3)reduced the maximum decomposition rate,but by comparing the chemical looping conversion characteristic index,it could be inferred that the chemical looping gasification of vitrinite might produce volatile substances higher than the pyrolysis process of vitrinite alone.The average activation energy of the reaction was significantly reduced during chemical looping gasification of vitrinite,which was lower than the average activation energy of 448.69 kJ·mol^(-1) during the pyrolysis process of vitrinite alone.The gaseous products were mainly CO and CO_(2).When the heating rate was 10℃·min^(-1),the highest activation energy for CH4 formation was 21.353 kJ·mol^(-1),and the lowest activation energy for CO formation was 9.7333 kJ·mol^(-1).This study provides basic data for exploring coal chemical looping gasification mechanism and reactor design by studying the chemical looping gasification process of coal macerals。
基金partially supported by the Graduate Student Research Grants from the Gulf Coast Association of Geological Societies (GCAGS)American Association of Petroleum Geologist (AAPG)by the University of Texas at Arlington and by the Pioneer Natural Resources
文摘Thermal maturity is commonly assessed by various geochemical screening methods(e.g.,pyrolysis and organic petrology).In this contribution,we attempt to establish an alternative approach to estimating thermal maturity with Raman spectroscopy,using 24 North American oil shale samples with thermal maturity data generated by vitrinite reflectance(VRo%)and pyrolysis(Tmax)-based maturity calculation(VRe%).The representative shale samples are from the Haynesville(East Texas),Woodford(West Texas),Eagle Ford and Pearsall(South Texas)Formations,as well as Gothic,Mancos,and Niobrara Formation shales(all from Colorado).The Raman spectra of disordered carbonaceous matter(D1 and G bands separation)of these samples were directly obtained from the rock chips without prior sample preparation.Using the Gaussian and Lorentzian distribution approach,thermal maturities from VR were correlated with carbon G and D1.We found that the Raman band separation(RBS)displayed a better correlation for equivalent VRe%than vitrinite reflectance VRo%.The RBS(D1–G)distance versus total organic carbon,free hydrocarbons from thermal extraction(S1),and the remaining hydrocarbon generating potential(S2)indicate that the RBS(D1–G)distance is also related to kerogen type.Data presented here from three methods of maturity determination of shale demonstrate that Raman spectroscopy is a quick and valid approach to thermal maturity assessment.
基金financially supported by grants from the Geological Survey Projects of China Geological Survey(grant nos.20242065,20230260)the Fundamental Research Fund of Chinese Academy of Geological Sciences(grant no.JKYQN202342)the National Natural Science Foundation of China(grant no.41772272)。
文摘Reconstructing the thermal evolution of the eastern Qaidam Basin is important for gaining a deeper understanding of its lithospheric geodynamics and for more accurate hydrocarbon evaluation and prediction.This article presents a set of new apatite and zircon(U-Th)/He thermochronological ages.Combined with 336 vitrinite reflectance(R_(o))data,the thermal history of the Ouanan Sag in the eastern Qaidam Basin has been reconstructed using inversion models.Three detrital samples from the Ounan Sag shows that the apatite(U-Th)/He ages are primarily concentrated in the range of 17.0 Ma to 76.5 Ma and that the zircon(U-Th)/He ages range from 200 Ma to 289.3 Ma.The time-temperature models demonstrate that the Ounan Sag experienced rapid subsidence and heating from the Carboniferous to late Permian,and exhumation/cooling events from the end of Permian to the Triassic.This thermal evolution was influenced by the widespread intrusion of plutons,and the collision and orogenesis caused by asthenosphere upwelling below the Qaidam arc,and slab rollback of the Southern Kunlun oceanic lithosphere,respectively.Additionally,our models depict the main exhumation/cooling stages since the Paleogene and a reheating event in the Miocene as a result of the intensifying growth of the Qinghai-Tibet Plateau and local sedimentary loading,followed by the initial India-Eurasia collision.Furthermore,the eastern Qaidam Basin experienced consistent heating during the late Paleozoic,reaching the maximum paleotemperature and geothermal gradient in the late Permian,with values of~230℃and~43-44℃/km,respectively.This study suggests that the source rocks in the most upper member of upper Carboniferous Keluke(C_(2)k)Formations in the Ounan Sag reached the gas generation stage in the late Permian.
基金This paper is supported by China Offshore Petroleum Exploration Development Corporation.
文摘Based on the models developed by Lerche et al. (1984) and Pang et al. (1993), an improved model for calculating paleoheat flow into basins is investigated. The new model is an optimization problem with the state variables governed by a thermal conduction equation. A genetic algorithm is used to solve the highly nonlinear optimization problem. As an application, the model is applied to the research into the history of heat flow in the Pearl River Mouth basin located in the South China Sea. The numerical analysis shows that the simulation results are in good agreement with the measured data and indicates that the basin may have undergone three rifting and thermal events. It is also demonstrated that a high R0 gradient reflects a response to high paleoheat flow during the early, rapid subsidence stage, while a low R0 gradient is a result of the thermal decay during the thermal subsidence because of thermal contraction of a cooling lithosphere.
文摘Three typical vitrinite reflectance (R0) proriles from Pearl River Mouth, Qiongdongnan and Beibuwan basins on the nortbern condsental shelf or the South China Sea display two or more different sub-linear slope relationships between IgR0 and deptb. According to the reconstruction of sedimentary and burial histories for these wells, a relatively large R0 gradient corresponds to a high depositional rate, while a relatively small R0 gradieut represeuts a low depositional rate. In this study, a modiried thermal backstripping model for paleokeat fIow using vitrinite reflectance data has been used to reconstruct paleotbermal history by the linear-segmeut regression. Tke study results indicate that the gentle parts of a IgR0 profile rerlect abnormai periods or high paleoheat flow, in contrast, the steep parts of a IgR0 profile reflect periods of peleoheat flow decay.In order to have an alternative approach and correlative study, an improved two-layer extensional model for the formation and evolution or rifting basin iu pesive contiueutal margin bas been applied. The model simulates basin subsidence process due to stretcbing and thinuing of continental lithospbere and thermal effects by asthenospbere upwelling, and determines the relationship between subsidence and paleoheat flux through the geological time. The simulation results suggest that these basins have undergone two or three rirting and thermal events, and it is clear that the large R0 gradient segment reflects a response to high paleoheat flow during the early, rapid subsidence stage, while the low R. gradient segmeut is a result or the tbermal decay during the thermal subsidence because of thermal contraction of a cooling Iitbospbere. The results also suggest that the maturity profiles of these basins can be employed to visual understanding tke paleogeothermal characteristics of rifting basins.
文摘Based on the Arrhenius equation and Karweil method, a simulation calculation has been made on the thermal maturation of organic matter under a series of assuming paleotem-perature gradients. Results show that there was a positive correlation of vitrinite reflectance gradient with paleotemperature gradient and vitrinite reflectance. According to this, a model
文摘The humilith series of lignite,longflame coal,gas coal,fat coal,coking coal,lean coal,meagre coal and anthracite are measured by FIR1600 infrared spectrophotometer.The variation curve between the infrared absorption wave number of aromaticring C--C bond of vitrinite and its reflectance values are gained,which shows the shift of infrared absorption wave number of aromaticring C--C bond of humic coals towards lower wave number with the increase of coalification.It is believed that the coal rank of humilith series can be determined and more evolutional information about coal composition and structure can be obtained by the infrared spectroscopic method.
文摘Kinetics study of gaseous hydrocarbons generated from vitrinites based on pyrolysis of gold tube closed system shows that the activation energies of methane generated from telocollinite are higher than that from desmocol-linite due to structure differences. But carbon isotope ratios of generated methane in pyrolysates of vitrinites at the same temperature points are similar. Carbon isotope ratio of methane may decrease in the early stage of gas generation and then increase in the later stage. But at higher temperature, δ13C1 decreases slightly or almost keeps stable with increasing temperature. Since it is known that carbon isotope distillation is controlled by time, temperature and carbon isotope ratio of bulk organic matter, the character of side chains connected to macromolecule of vitrinite and distribution of activation energies have no obvious effect on carbon isotope fraction. Decreasing trend of δ13C1 in the early stage may be caused by contagious structure of vitrinite or differences of
基金supported by National Natural Science Foundation of China(Nos.42202172,U24B6001,41830424)the Fundamental Research Funds for the Central Universities,CHD(300102274202).
文摘The absence of humic vitrinite complicates the determination of thermal maturity in pre-Devonian sediments.Lower Paleozoic shales contain structured zooclasts,solid bitumen,and vitrinite-like materials,and their reflectances have been found to be valid maturity proxies.Yet there remains much controversy as to the degree of evolution of reflectances.The current work aims to investigate the reflectance of dispersed organic matter(DOM),as well as their transformation degree and organic pore development.To this end,this study evaluated an Upper Ordovician zooclasts-bearing shale and a Middle Jurassic coal sample via anhydrous-pyrolysis to compare differences in the maturation pathways between marine-derived DOM and terrigenous vitrinite.These two original samples were cut into small blocks and placed in an identical vacuum stainless vessel simultaneously.The pyrolysis was carried out at isothermal temperatures ranging from 250 to 550℃ for 48 h.The morphologic and reflectance changes of DOM in pyrolysis residues were studied and compared with previous pyrolysis results.Adopting the combined use of optical reflectance and scanning electron microscope(SEM)techniques,the study shows that DOM in the shale components consists of solid bitumen(SB),bituminite,chitinozoans,a few graptolites,vitrinite-like particles(VLP),alginate and liptodetrinite.The reflectance sequence,from high to low,is zooclasts,VLP and SB.Their reflectances gradually increases as the pyrolysis temperature rises,although the rate of growth is slower than that of co-heating coal vitrinite.Notably,zooclasts yield significantly higher reflectance values than those of VLP and SB at each pyrolysis temperature.However,the VLP undergoes two distinct phases in reflectance development,despite gradual morphology changes similar to vitrinite.Based on evidence of the optical texture and organic pore evolution,we argue that a fair amount of VLP in studied Upper Ordovician shale does not consist of graptolite-type fragments.Consequently,the VLPRo serves as a reliable indicator for assessing organic matter maturity in Ordovician shales with a reflectance value of less than 2.0%.This investigation enhances scholarly understandings of marine-derived DOM evolution issues,providing clearer correlations among reflectances of different DOM and reducing uncertainties in thermal maturity determination.
基金funding from the Strategic project‘Technologies of Sustainable Development’of Program of strategic academic leadership‘Priority 2030’of NUST MISIS.
文摘The paper contains the results of investigation of interconnections between coals’vitrinite structural features,mode of its crushing under the cyclic nanoindentation with increasing peak load and coals’proneness to formation of airborne respirable dust(ARD)with particles sized<10μm(PM10).A specific value of PM10 contents in coals normalized on a fines fraction(with particles sizes of less than 200μm)was used as a measure of proneness to ARD formation.It has been shown that the aforementioned parameter is predefined by the ratio of amorphous and crystalline carbon compounds in vitrinite and the mode of its crushing.Some preliminary investigation have been done in order to characterize the involvement of inertinite in ARD formation.It was proposed that the inertinite is not as actively involved in the processes of ARD formation of coals as vitrinite,having a more diverse structural features in terms of amorphous to crystalline carbon compounds ratio.
基金Social Policy Grant(064.01.00 SPG)financed by Nazarbayev University,Kazakhstan。
文摘This study comprises the relationship between organic matter(OM)and gold occurrence using two distinctive ore deposits of the Bakyrchik gold-sulfide deposit(Kazakhstan)and Western Mecsek uranium ore deposit(Hungary).The two ore deposits are identified as organicrich sedimentary formations linked to the Variscan gold cycle globally.Characterizing OM is essential because it can act as a carrier for gold,influencing its distribution and behavior within the deposit.Understanding the nature and distribution of OM can provide insights into the processes of gold deposition and help optimize exploration and extraction strategies in mining operations.The primary objective is to characterize OM by identifying its elemental composition,thermal maturity,functional groups,and soluble fractions;and extract gold from OM using a two-step sequential extraction method(hydrogen peroxide and aqua regia)combined with geochemical techniques.Analytical and experimental results from samples of both ore deposits indicate the presence of finely disseminated solid bitumen and reworked vitrinite,originating from thermally matured(RmcRo%—3.76 in Bakyrchik;Ro%—2.25 in W-Mecsek)terrigenous high plants.Both deposits exhibit extremely low extractable bitumen yield and TOC(0.34%in Bakyrchik;0.25 wt%in W-Mecsek),characterized by an aromatic carboxylic acid organic structure and a composition rich in sulfur-containing(1.17%in Bakyrchik;5.81%in W-Mecsek)aromatic hydrocarbons.Gold occurrence and enrichment within OM were confi rmed through the sequential extraction method employing ICP-OES and LA-ICP-MS techniques.The sequentially extracted gold content from OM reached up to 3 ppm in Bakyrchik and up to 3.28 ppm in Western Mecsek,accompanied by Ag(ranging from 0.01 to 0.32 ppm).Higher concentrations of Au(4 ppm)and Ag(27 ppm)were extracted from residue materials,which are likely associated with sulfide minerals.The presence of gold in OM was further validated using LA-ICP-MS.Gold bonding within OM structure,gold is preserved in the form of lattice gold or structurally bonded metal most likely within the aromatic hydrocarbon fractions of the OM in both the W-Mecsek and Bakyrchik deposits.These findings underscore the profound potential of ongoing exploration endeavors,off ering pivotal revelations regarding the extraction and practical application of Au and Ag derived from OM within the geochemical framework of both ore deposits.
基金The National Natural Science Foundation of China (Nos. 41402219, 41125010, and 91114202)the Key State Science and Technology Project (No. 2011ZX05006) provided the financial support
文摘The thermal history of sedimentary basins is a key factor for hydrocarbon accumulation and resource assessment, and is critical in the exploration of lithospheric tectono-thermal evolution. In this paper, the Cenozoic thermal histories of nearly 200 wells and the Mesozoic thermal histories of 15 wells are modeled based on the vitrinite reflectance and apatite fission track data in Bohai Bay Basin, North China. The results show that the basin experienced Early Cretaceous and Paleogene heat flow peaks, which reveals two strong rift tectonic movements that occurred in the Cretaceous and the Paleogene in the basin, respectively. The thermal evolution history in Bohai Bay Basin can be divided into five stages including（1） the low and stable heat flow stage from the Triassic to the Jurassic, with the heat flow of 53 to 58 m W/m2;（2） the first heat flow peak from the Early Cretaceous to the middle of the Late Cretaceous, with a maximum heat flow of 81 to 87 m W/m2;（3） the first post-rift thermal subsidence stage from the middle of the Late Cretaceous to the Paleocene, with the heat flow of 65 to 74 m W/m2 at the end of the Cretaceous;（4） the second heat flow peak from the Eocene to the Oligocene, with a maximum heat flow of 81 to 88 m W/m2; and（5） the second thermal subsidence stage from the Neogene to present, with an average heat flow of 64 m W/m2.
基金supported by the National Science Fundamental of China Project(No.40773040)by the project of the Science Foundation of Hebei(Nos. D2009000832 and D2008000727).
文摘In order to study the accumulation mechanism of＂barkinite＂,eight Late Permian channel benches（approximately 15-cm across and 10-cm deep） were taken from the Jinshan Mine,Anhui Province,China.The samples were analyzed by microscopical and geochemical methods.The microscopical observations indicate that the occurrence modes of＂barkinite＂in this area are different from those in other areas of China.The ratios of structureless＂barkinite＂are much higher in the Jinshan Mine,probably due to the flow-water and marine influenced environments.Furthermore, vitrinite macerals also show a strong fluorescence.The vitrinite fluorescence characteristics have not been observed in the Permian＂barkinite＂coals from northern China.The composition and variation of minerals in the column section also showed that the swamps in the study area were seriously influenced by seawater in the early and late stage during the peat accumulation.
文摘Using well logs data only, the evaluation of shale gas hydrocarbon potential of Talhar Shale Member of Lower Goru Formation has been a challenge in Southern Lower Indus Basin in Pakistan. Well logs data analysis is helpful to evaluate the gas potential of source shale rocks. We introduced and applied empirical and graphical method to fulfil this task and derived geochemical parameters from well logs data. The method mentioned is cheap and fast. Talhar Shale has kerogen type Ⅲ and type Ⅱ which are montmorillonite clay and have potential to produce oil and gas. Talhar Shale has better sorption property. Empirical formulas are used to derive parameters, using well logs of porosity, density and uranium. Porosity and volume of kerogen, calculated from density log, give average values of 11.8% and 11.4%. Average value of level of maturity index （LMI） derived from log is 0.54, which indicates that it is at the early stage of maturity. Vitrinite reflectance is between 0.5%-0.55% as calculated by graphical method and empirical formula. Talhar Shale is at onset of oil generation, with main products of oil and gas. It is a good potential source in the study area.
基金supported by the National Natural Science Foundation of China (No.40730422)the National Science and Technology Key Special Project of China (No.2011ZX05034)the Fundamental Research Funds for the Central Universities of China (No.2010QNA51)
文摘Coalbed gas （CBG） in Enhong syncline, eastern Yunnan China, is character- ized by high concentration of heavy hydrocarbon with the highest content of ethane, which is more than 30%. Some previous investigators paid much attention to the abnormal concentration of heavy hydrocar- bon in the CBG of Enhong, but few have researched on its origin. This article describes the characteristics of abnormal high concentration of heavy hydrocarbon in Enhong syncline and analyzes its reason from the aspects of origin and evolution of heavy hydrocarbon by carbon isotope, coal petrography, and coal rank. Features of gas carbon isotope composition display that there is no inorganic gas or off components in the CBG, which is classified to thermogenetic gas produced by humic material, with characteristic of secondary biogenic gas in shallow coal seam. The concentration of heavy hydrocarbon in Enhong syncline increases with the increase of vitrinite, vitrinite/inertinite ratio, and hydrogen/carbon ratio and decreases with the increase of inertinite, so hydrogen-rich vitrinite may be a very important factor resulting in the abnormal concentration of heavy hydrocarbon. It also increases with the increase of degree of coalifica-tion of coking to lean coals during which the peak of heavy hydrocarbon generation is reached. Therefore, we think that high concentration of heavy hydrocarbon originated from the coupling effect of higher content of the hydrogen-rich vitrinite in the coal and the coal rank of coking to lean coals.
基金supported by the National Key Basic Research Development Plan of China(No.2012CB214703)the National Natural Science Foundation of China(No.41102152)+1 种基金the Petro China Innovation Foundation(No.2013D-5006-0102)the Science Foundation of China University of Petroleum,Beijing(No.YJRC2013-002)
文摘The thermal history and organic matter maturity evolution of the source rocks of boreholes in the Puguang gas field were reconstructed. An integrated approach based on vitrinite reflectance and apatite fission track data was used in the reconstruction. Accordingly, the geothermal conditions of gas accumulation were discussed in terms of the geological features of reservoirs in the northeastern Sichuan Basin. The strata reached their maximum burial depth in the Late Cretaceous era and were then uplifted and denuded continuously to the present day. The geothermal gradient and heat flow in the Late Cretaceous era were approximately 30.0 °C/km and 66 mW/m2, respectively, which were both higher than those at present. The tectonothermal evolution from the Late Cretaceous era to the present is characterized by denudation and cooling processes with an erosion thickness of2.7 km. In addition to the Triassic era, the Jurassic era represents an important hydrocarbon generation period for both Silurian and Permian source rocks, and the organic matter maturity of these source rocks entered into a dry gas period after oil generation. The thermal conditions are advantageous to the accumulation of conventional and unconventional gas because the hydrocarbon generation process of the source rocks occurs after the formation of an effective reservoir cap. In particular, the high geothermal gradient and increasing temperature before the denudation in the Late Cretaceous era facilitated the generation of hydrocarbons, and the subsequent cooling process favored its storage.
文摘Thermal maturation and petroleum generation modeling of shales is essential for suc- cessful exploration and exploitation of conventional and unconventional oil and gas plays. For basin- wide unconventional resource plays such modeling, when well calibrated with direct maturity meas- urements from wells, can characterize and locate production sweet spots for oil, wet gas and dry gas. The transformation of kerogen to petroleum is associated with many chemical reactions, but models typically focus on first-order reactions with rates determined by the Arrhenius Equation. A miscon- ception has been perpetuated for many years that accurate thermal maturity modeling of vitrinite re- flectance using the Arrhenius Equation and a single activation energy, to derive a time-temperature index （~TTIARa）, as proposed by Wood （1988）, is flawed. This claim was initially made by Sweeney and Burnham （1990） in promoting their ＂EasyRo＂ method, and repeated by others. This paper dem- onstrates through detailed multi-dimensional burial and thermal modeling and direct comparison of the ~TTIARR and ＂EasyRo＂ methods that this is not the case. The ~TTIA^R method not only provides a very useful and sensitive maturity index, it can reproduce the calculated vitrinite reflectance values derived from models based on multiple activation energies （e.g., ＂EasyRo＂）. Through simple expres- sions the ~TTIAaa method can also provide oil and gas transformation factors that can be flexibly scaled and calibrated to match the oil, wet gas and dry gas generation windows. This is achieved in a more-computationally-efficient, flexible and transparent way by the ~TTIARR method than the ＂EasyRo＂ method. Analysis indicates that the ＂EasyRo＂ method, using twenty activation energies and a constant frequency factor, generates reaction rates and transformation factors that do not realisti- cally model observed kerogen behaviour and transformation factors over geologic time scales.
文摘The pyrolysis characteristics of Shendong Shangwan coal and its macerals concentrate were investigated using thermogravimetry （TG） coupled with mass spectrometry （MS）. The evolved gases were analyzed online by MS spectroscopy. The results of TG/DTG （derivative thermogravimetry） show ths vitrinite concentrate has greater weight loss rate and higher volatile yield than the other two samples. More light hydrocarbons C1-C5 are released from the vitfinite concentrate than from the Shendong Shangwan coal and inertinite concentrated in the process of pyrolysis. Three samples have similar shape curves of evolved gases of C2~C5 with different intensities. When the pyrolysis temperature was lower than 418℃, the amount of C6H6 evolved in the process of pyrolysis of inertinite concentrated was higher than that of raw coal and vitrinite concentrate. As the temperature rising, the production rate of C6H6 increased. Below 672℃, C6H6 evolution rate of vitrinite concentrate was far greater than the other two samples; the main evolution temperature range of C7H8 was 400℃ to 700℃ for the three samples. The amount of HE and H20 released first increased and then decreased with the temperature increase while more H2 released for pyrolysis of inertinite concentrated and more H20 released for the pyrolysis of vitrinite concentrate.
