Thermochemical sulfate reduction(TSR)is an important organic-inorganic reaction that occurs within sedimentary basins and alters the original chemical compositions and isotopic structures of hydrocarbons in natural ga...Thermochemical sulfate reduction(TSR)is an important organic-inorganic reaction that occurs within sedimentary basins and alters the original chemical compositions and isotopic structures of hydrocarbons in natural gases.We used the GC-Py-GC-IRMS method to study TSR and obtained a novel finding related to intramolecular carbon isotope fractionation in natural propane.The results show that theΔC-T(δ^(13)C_(central)-13 C_(terminal))andδ^(13)C_(central)values significantly increased to 44.7‰and 11.9‰,respectively,with increasing TSR alteration.In contrast,the 13 C_(terminal)values of propane remained largely unaltered by the TSR reaction.This difference in position-specific isotope fractionation can be attributed to the central carbon’s reactivity being higher than that of terminal carbon during TSR.In sum,the results indicate that theδ^(13)C_(terminal)values of propane can serve as robust indicators for source rock identification of natural gas altered by post-generation reactions such as TSR and anaerobic microbial oxidation.展开更多
在悬浮磁偶极场约束装置中,姿态控制系线圈(Tilt-Slide-Rotate,TSR)或者由高能量的粒子共振(Resonant Line Field,RLF)激发磁场会破坏背景磁场的拓扑结构,进而影响粒子约束。由于α粒子是DD-3He催化核反应产物之一,能否在TSR线圈和RLF...在悬浮磁偶极场约束装置中,姿态控制系线圈(Tilt-Slide-Rotate,TSR)或者由高能量的粒子共振(Resonant Line Field,RLF)激发磁场会破坏背景磁场的拓扑结构,进而影响粒子约束。由于α粒子是DD-3He催化核反应产物之一,能否在TSR线圈和RLF效应产生的磁场扰动中稳定约束高能量α粒子,对于加热背景等离子体的研究具有非常重要的意义。本研究中背景磁偶极场是通过偶极场平衡代码求解一个交换稳定的平衡得到的,在TSR线圈倾斜和偏移的工作模式下,对粒子投掷位置和TSR线圈工作电流α粒子约束时间和空间特性进行统计,同时在背景磁偶极场中叠加环向磁场方法模拟低极向扰动模数的磁场。由于TSR线圈产生磁场会破坏背景磁偶极场闭合磁场线的结构,使得投掷位置靠近TSR线圈侧的α粒子迅速损失。在RLF效应引发的模数n=0和n=1的极向扰动磁场中,在10μs内,n=0极向扰动磁场比n=1的磁扰动约束粒子份额更高,且当α粒子飞行时间大于10μs后,n=0模式下约束粒子份额迅速减少。展开更多
Thiadiamondoids(TDs)have recently attracted increasing attention as molecular proxies for thermochemical sulfate reduction(TSR)reactions in reservoirs.However,their formation mechanisms,as well as the generation and e...Thiadiamondoids(TDs)have recently attracted increasing attention as molecular proxies for thermochemical sulfate reduction(TSR)reactions in reservoirs.However,their formation mechanisms,as well as the generation and evolution processes,remain poorly understood.In this study,simulation experiments with a duration of 160 h were conducted on the model compound 1,3-dimethyladamantane(1,3-DMA)using the CaSO_(4),MgSO_(4),and elemental S systems,with measurements at the 10th,20th,40th,80th and 160th hours during the simulation process being presented.The results indicate that at the end of simulation,the MgSO_(4) system exhibited the lowest residual amounts of 1,3-DMA,suggesting the highest degree of TSR.Four types of non-hydrocarbon compounds with adamantane structures were detected in the liquid products in the three experiment systems:adamantanones,adamantanols,adamantanethiols(ATs),and thiaadamantanes(TAs).Among these,adamantanones exhibited the highest concentrations in the three simulation systems.In addition,TAs were dominated by C_(3)-TAs in the CaSO_(4) and MgSO_(4) systems and by C_(2)-TAs in the elemental S system.The simulation experiments revealed a strong correlation between the concentrations of TAs and adamantanones,suggesting that adamantanones might be the intermediates for TAs.Combined with the synthesis mechanism of TAs from thiaadamamantane-4,8-dione,TDs might have two different genetic mechanisms:(a)low temperature cationic carbon ion rearrangement from diagenesis to early catagenesis stage,and(b)a free sulfur radical mechanism in high-temperature TSR process during middle-late catagenesis.TAs exhibited different generation and evolution processes across different experiment systems.Notably,the MgSO_(4) system revealed that TAs undergo generation,accumulation,and destruction process,corresponding to Easy%Ro values of 0.89%-0.98%,0.98%-1.21%,and>1.21%,respectively.Among these three simulation systems,dibenzothiophenes(DBTs)concentrations consistently trended upwards,indicating TAs have lower thermal stability than DBTs.展开更多
Taking the natural gas reservoirs of the Sinian Dengying Formation on the east and west sides(Gaoshiti-Moxi area and north slope of central Sichuan paleo-uplift on the east;Weiyuan and Well Datan-1 block on the west)o...Taking the natural gas reservoirs of the Sinian Dengying Formation on the east and west sides(Gaoshiti-Moxi area and north slope of central Sichuan paleo-uplift on the east;Weiyuan and Well Datan-1 block on the west)of the Deyang-Anyue rift trough in the Sichuan Basin,China,as the research object,the geochemical parameters(component,isotopic composition)of natural gas from the Dengying Formation in different areas are compared,and then the differences in geochemical characteristics of Dengying natural gas on the east and west sides of the Deyang-Anyue rift trough and their genesis are clarified.First,the Dengying gas reservoirs on both sides of the rift trough are predominantly composed of oil-cracking gas with high maturity,which is typical dry gas.Second,severely modified by thermochemical sulfate reduction(TSR)reaction,the Dengying gas reservoirs on the east side exhibit high H2S and CO_(2) contents,with an elevated δ^(13)C_(2) value(average value higher than-29‰).The Dengying gas reservoirs in the Weiyuan area are less affected by TSR modification,though the δ^(13)C_(1) values are slightly greater than that of the reservoirs on the east side with partial reversal of carbon isotope composition,likely due to the water-soluble gas precipitation and accumulation mechanism.The Dengying gas reservoir of Well Datan-1 shows no influence from TSR.Third,the Dengying gas reservoirs reflect high helium contents(significantly higher than that on the east side)in the Weiyuan and Datan-1 areas on the west side,which is supposed to attribute to the widespread granites in basement and efficient vertical transport along faults.Fourth,controlled by the paleo-salinity of water medium in the depositional period of the source rock,the δ^(2)HCH_(4) values of the Dengying gas reservoirs on the west side are slightly lighter than those on the east side.Fifth,the Dengying natural gas in the Datan-1 area is contributed by the source rocks of the Sinian Doushantuo Formation and the third member of the Dengying Formation,in addition to the Cambrian Qiongzhusi Formation.展开更多
基金supported by the Helium Enrichment and Detection in Natural Gas Reservoirs Related to Oil and Gas Fields project(Grant No.2025ZD1010500)the Deep Earth Probe and Mineral Resources Exploration―National Science and Technology Major Project.-。
文摘Thermochemical sulfate reduction(TSR)is an important organic-inorganic reaction that occurs within sedimentary basins and alters the original chemical compositions and isotopic structures of hydrocarbons in natural gases.We used the GC-Py-GC-IRMS method to study TSR and obtained a novel finding related to intramolecular carbon isotope fractionation in natural propane.The results show that theΔC-T(δ^(13)C_(central)-13 C_(terminal))andδ^(13)C_(central)values significantly increased to 44.7‰and 11.9‰,respectively,with increasing TSR alteration.In contrast,the 13 C_(terminal)values of propane remained largely unaltered by the TSR reaction.This difference in position-specific isotope fractionation can be attributed to the central carbon’s reactivity being higher than that of terminal carbon during TSR.In sum,the results indicate that theδ^(13)C_(terminal)values of propane can serve as robust indicators for source rock identification of natural gas altered by post-generation reactions such as TSR and anaerobic microbial oxidation.
文摘在悬浮磁偶极场约束装置中,姿态控制系线圈(Tilt-Slide-Rotate,TSR)或者由高能量的粒子共振(Resonant Line Field,RLF)激发磁场会破坏背景磁场的拓扑结构,进而影响粒子约束。由于α粒子是DD-3He催化核反应产物之一,能否在TSR线圈和RLF效应产生的磁场扰动中稳定约束高能量α粒子,对于加热背景等离子体的研究具有非常重要的意义。本研究中背景磁偶极场是通过偶极场平衡代码求解一个交换稳定的平衡得到的,在TSR线圈倾斜和偏移的工作模式下,对粒子投掷位置和TSR线圈工作电流α粒子约束时间和空间特性进行统计,同时在背景磁偶极场中叠加环向磁场方法模拟低极向扰动模数的磁场。由于TSR线圈产生磁场会破坏背景磁偶极场闭合磁场线的结构,使得投掷位置靠近TSR线圈侧的α粒子迅速损失。在RLF效应引发的模数n=0和n=1的极向扰动磁场中,在10μs内,n=0极向扰动磁场比n=1的磁扰动约束粒子份额更高,且当α粒子飞行时间大于10μs后,n=0模式下约束粒子份额迅速减少。
基金funded by the Natural Science Foundation of China(Grants Nos.42272167,U24B6001,and 41772153)Science&Technology Project of Sinopec(Grant Nos.P23167 and P24173).
文摘Thiadiamondoids(TDs)have recently attracted increasing attention as molecular proxies for thermochemical sulfate reduction(TSR)reactions in reservoirs.However,their formation mechanisms,as well as the generation and evolution processes,remain poorly understood.In this study,simulation experiments with a duration of 160 h were conducted on the model compound 1,3-dimethyladamantane(1,3-DMA)using the CaSO_(4),MgSO_(4),and elemental S systems,with measurements at the 10th,20th,40th,80th and 160th hours during the simulation process being presented.The results indicate that at the end of simulation,the MgSO_(4) system exhibited the lowest residual amounts of 1,3-DMA,suggesting the highest degree of TSR.Four types of non-hydrocarbon compounds with adamantane structures were detected in the liquid products in the three experiment systems:adamantanones,adamantanols,adamantanethiols(ATs),and thiaadamantanes(TAs).Among these,adamantanones exhibited the highest concentrations in the three simulation systems.In addition,TAs were dominated by C_(3)-TAs in the CaSO_(4) and MgSO_(4) systems and by C_(2)-TAs in the elemental S system.The simulation experiments revealed a strong correlation between the concentrations of TAs and adamantanones,suggesting that adamantanones might be the intermediates for TAs.Combined with the synthesis mechanism of TAs from thiaadamamantane-4,8-dione,TDs might have two different genetic mechanisms:(a)low temperature cationic carbon ion rearrangement from diagenesis to early catagenesis stage,and(b)a free sulfur radical mechanism in high-temperature TSR process during middle-late catagenesis.TAs exhibited different generation and evolution processes across different experiment systems.Notably,the MgSO_(4) system revealed that TAs undergo generation,accumulation,and destruction process,corresponding to Easy%Ro values of 0.89%-0.98%,0.98%-1.21%,and>1.21%,respectively.Among these three simulation systems,dibenzothiophenes(DBTs)concentrations consistently trended upwards,indicating TAs have lower thermal stability than DBTs.
基金Supported by the National Natural Science Foundation of China(42272161)PetroChina Science and Technology Major Project(2023ZZ16)Research Institute of Exploration and Development,PetroChina Southwest Oil&Gasfield Company(2024D101-01-06)。
文摘Taking the natural gas reservoirs of the Sinian Dengying Formation on the east and west sides(Gaoshiti-Moxi area and north slope of central Sichuan paleo-uplift on the east;Weiyuan and Well Datan-1 block on the west)of the Deyang-Anyue rift trough in the Sichuan Basin,China,as the research object,the geochemical parameters(component,isotopic composition)of natural gas from the Dengying Formation in different areas are compared,and then the differences in geochemical characteristics of Dengying natural gas on the east and west sides of the Deyang-Anyue rift trough and their genesis are clarified.First,the Dengying gas reservoirs on both sides of the rift trough are predominantly composed of oil-cracking gas with high maturity,which is typical dry gas.Second,severely modified by thermochemical sulfate reduction(TSR)reaction,the Dengying gas reservoirs on the east side exhibit high H2S and CO_(2) contents,with an elevated δ^(13)C_(2) value(average value higher than-29‰).The Dengying gas reservoirs in the Weiyuan area are less affected by TSR modification,though the δ^(13)C_(1) values are slightly greater than that of the reservoirs on the east side with partial reversal of carbon isotope composition,likely due to the water-soluble gas precipitation and accumulation mechanism.The Dengying gas reservoir of Well Datan-1 shows no influence from TSR.Third,the Dengying gas reservoirs reflect high helium contents(significantly higher than that on the east side)in the Weiyuan and Datan-1 areas on the west side,which is supposed to attribute to the widespread granites in basement and efficient vertical transport along faults.Fourth,controlled by the paleo-salinity of water medium in the depositional period of the source rock,the δ^(2)HCH_(4) values of the Dengying gas reservoirs on the west side are slightly lighter than those on the east side.Fifth,the Dengying natural gas in the Datan-1 area is contributed by the source rocks of the Sinian Doushantuo Formation and the third member of the Dengying Formation,in addition to the Cambrian Qiongzhusi Formation.
