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
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
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
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
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
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 .
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.
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。
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.
