Bitumen from the Nanpanjiang Basin occurs mainly in the Middle Devonian and Upper Permian reef limestone paleo-oil reservoirs and reserves primarily in holes and fractures and secondarily in minor matrix pores and bio...Bitumen from the Nanpanjiang Basin occurs mainly in the Middle Devonian and Upper Permian reef limestone paleo-oil reservoirs and reserves primarily in holes and fractures and secondarily in minor matrix pores and bio-cavities. N2 is the main component of the natural gas and is often associated with pyrobitumen in paleo-oil reservoirs. The present study shows that the bitumen in paleo-oil reservoirs was sourced from the Middle Devonian argillaceous source rock and belongs to pyrobitumen by crude oil cracking under high temperature and pressure. But the natural gas with high content of N2 is neither an oil-cracked gas nor a coal-formed gas generated from the Upper Permian Longtan Formation source rock, instead it is a kerogen-cracked gas generated at the late stage from the Middle Devonian argilla- ceous source rock. The crude oil in paleo-oil reservoirs completely cracked into pyrobitumen and methane gas by the agency of hugely thick Triassic deposits. After that, the abnormal high pressure of methane gas reservoirs was completely destroyed due to the erosion of 2000--4500-m-thick Triassic strata. But the kerogen-cracked gas with normal pressure was preserved under the relatively sealed condition and became the main body of the gas shows.展开更多
A fluid inclusion fluorescence and microthermometric study was performed on sandstones from the deep Es4 reservoir rocks of the Minfeng （民丰） sag, north of Dongying （东营） depression. Two types of oil inclusions ...A fluid inclusion fluorescence and microthermometric study was performed on sandstones from the deep Es4 reservoir rocks of the Minfeng （民丰） sag, north of Dongying （东营） depression. Two types of oil inclusions （yellow and blue white fluorescence）, one type of gas inclusions （blue white fluorescence）, and bitumen inclusions （no fluorescence） were detected within quartz and feldspar minerals. The evolution of hydrocarbon fluid inclusions in the lower Es4 sequence indicates that present oil accumulation was predominantly thermal stress controlled. Homogenization temperatures of aqueous fluid inclusions coexisting with gas-bearing and bitumen-bearing fluid inclusions indicate that oil cracking occurred at temperatures up to 160 ℃, primary condensate or wet gas genera- tion occurred during 170-195℃. Oil has cracked into condensate or wet gas in the depth of 4 300- 4 410 m and dry gas and abundant pyrobitumen in the depth of more than 4 410 m in the geological history based on the fluid inclusion extrapolation. Secondary oil cracking is undergoing in present day when the depth of reservoir is more than 4 150 m whose temperature is the threshold temperature of oil cracking （160 ℃）. However, because of the consumption of oil in the first oil cracking process, it may have few chances to find liquid petroleum, and only natural gas can be found when the depth of reservoir is more than 4 410 m, where oil cracks into condensate gas or wet gas according to present-day formation temperature. This study is preliminary but foreshadows a new insight into oilcracking using natural fluid inclusions to trace hydrocarbon evolution in sedimentary basins.展开更多
A study of reaction mechanisms and chemical kinetics of pressurized pyrolysis of Chinese Liushuhe oil shale in the presence of water were conducted using an autoclave for simulating and modeling in-situ underground th...A study of reaction mechanisms and chemical kinetics of pressurized pyrolysis of Chinese Liushuhe oil shale in the presence of water were conducted using an autoclave for simulating and modeling in-situ underground thermal degradation.It was found that the oil shale was first pyrolyzed to form pyrobitumen,shale oil,shale gas and residue,then the pyrobitumen was further pyrolyzed to form more shale oil,shale gas,and residue.It means that there are two consecutive and parallel reactions.With increasing temperature,the pyrobitumen yield,as intermediate,first reached a maximum,then decreased to approximately zero.The kinetics results show that both these reactions are first order.The activation energy of pyrobitumen formation from oil shale is lower than that of shale oil formation from pyrobitumen.展开更多
The Neoproterozoic-Lower Paleozoic dolostone gas reservoirs in the Chuanzhong Uplift in Southwestern China contain the mesophase pyrobitumen (pyrobitumen with mesophase). The mesophase in the pyrobitumen is mostly com...The Neoproterozoic-Lower Paleozoic dolostone gas reservoirs in the Chuanzhong Uplift in Southwestern China contain the mesophase pyrobitumen (pyrobitumen with mesophase). The mesophase in the pyrobitumen is mostly composed of a mixture of condensed macromolecule polycyclic aromatic hydrocarbons (PAH), and has been mostly converted to various grain, flow, and domain textures. The volcanic activity nearby the Chuanzhong Uplift may have generated very hot (over 300 °C) hydrothermal fluid, with migration of the fluid into the dolostone reservoir transforming the hydrocarbons in the reservoir into an anisotropic carbon by-product, which formed under high temperature and pressure conditions;over 300 °C and 200 MPa according to fluid inclusion analysis. The high temperature-pressure in reservoir was caused by sudden devolatilization of the hydrocarbons due to hydrothermal heating, which formed the unusual texture of the mesophase. The elliptical mesophase grains (EG), the honeycomb structure of pyrobitumen, and the occurrence of polarized classes of mesophase in single pyrobitumen deposits are all unusual textures. This study investigates the texture development of this pressure-affected pyrobitumen. Observation and study of the mesophase suggest that the class of mesophase in pyrobitumen is determined by temperature, while pressure (assessed from associated fluid inclusions) significantly affected the texture. Analysis of the texture of the pyrobitumen in conjunction with previous thermometry results from methane inclusions suggests that the high class mesophase of the pyrobitumen could be applied as a temperature indicator for geological conditions. Furthermore, the unusual textures of the pyrobitumen including elliptical mesophase grains (EG), the honeycomb structure of pyrobitumen, and the occurrence of polarized classes of mesophase in single pyrobitumen could reflect the abnormal high formation pressure.展开更多
Maturity evaluation of highly evolved organic matter is an important problem in oil and gas geochemistry,because conventional organic geochemical proxies are not applicable due to hydrocarbon generation and expulsion....Maturity evaluation of highly evolved organic matter is an important problem in oil and gas geochemistry,because conventional organic geochemical proxies are not applicable due to hydrocarbon generation and expulsion.In this study,we investigated the pyrobitumen in the reservoirs of the Sinian Dengying Formation in the Sichuan Basin,China.We focused on aromatic hydrocarbon biomarkers,and the calibration and application of aromatic maturity proxies using pyrobitumen reflectance and Raman spectral parameters.Our results show that only the thiophene compounds are effective maturity indicators,such as MDR(4-/1-MDBT),MDR′(4-MDBT/(1-MDBT+4-MDBT)),MDR1(1-MDBT/DBT),4,6-/(1,4+1,6)-DMDBT,(2,6+3,6)-/(1,4+1,6)-DMDBT,and[2,1]BNT/([2,1]BNT+[1,2]BNT),as these are largely independent of the optical anisotropy of pyrobitumen.The condensation and incorporation of thiophene compounds can lead to an increase in the reflectance of pyrobitumen,which means the thiophene compound parameters are positively or negatively correlated with pyrobitumen reflectance.New potential maturity parameters were proposed,including DMDBTs/MDBTs,TeMDBTs/(DBT+MDBTs+DMDBTs+TMDBTs+TeMDBTs),1-MDBT/MDBTs,and[2,1]BNT/BNTs.This method and these parameters are universally applicable to maturity characterization,especially in rocks that lack vitrinite,contain strongly anisotropic organic matter,and have high contents of thiophene compounds.展开更多
The paper comprises new analytical data on the nature and occurrence of gold in solid pyrobitumen,closely associated with the main gold-bearing sulfide arsenic ores of the Bakyrchik gold deposit(Kazakhstan),related to...The paper comprises new analytical data on the nature and occurrence of gold in solid pyrobitumen,closely associated with the main gold-bearing sulfide arsenic ores of the Bakyrchik gold deposit(Kazakhstan),related to post-collisional magmatic-hydrothermal origin.Gold mineralization of the deposit occurs mainly in the form of an“invisible”type of gold in the structures of arsenian pyrite and arsenopyrite,and the form of gold-organic compounds of pyrobitumen in carbonaceous-terrigenous sequences of Carboniferous formation.Microscopic and electron microscopic analysis,Raman and FT-Infrared analysis,mineralogical and three-step sequential extraction analysis(NH2OHHCl,H2O2,HNO3?HCl)has been carried out using 9 ore samples(from 3 different types of ores)for a comprehensive study of pyrobitumen and sulfide arsenic ores focusing mainly on organic matter.The sequentially extracted precious metal content of pyrobitumen reaches up to 7 ppm gold and other metals like Ag 4 ppm,Pt 31 ppb,and Pd 26 ppb,forming metal–organic compounds,while arsenic sulfide minerals incorporate 11 ppm gold,39 ppm Ag,0.49 ppm Pt.The enrichment of gold associating with organic matter and sulfide ore minerals was confirmed in this study.Organic matter was active in the migration of gold and the capture of gold by pyrobitumen.Moreover,the reductive organic matter agent released gold,most likely for the sulfide arsenic ore minerals.Pyrobitumen was a decisive factor in the concentration,transportation,and preservation of gold in the deposit.展开更多
基金Supported by the Sinopec Project (Grant No: P00045)the National Science & Technology Project for the 10th Five-Year Plan (Grant No. 2001BA605A-06)
文摘Bitumen from the Nanpanjiang Basin occurs mainly in the Middle Devonian and Upper Permian reef limestone paleo-oil reservoirs and reserves primarily in holes and fractures and secondarily in minor matrix pores and bio-cavities. N2 is the main component of the natural gas and is often associated with pyrobitumen in paleo-oil reservoirs. The present study shows that the bitumen in paleo-oil reservoirs was sourced from the Middle Devonian argillaceous source rock and belongs to pyrobitumen by crude oil cracking under high temperature and pressure. But the natural gas with high content of N2 is neither an oil-cracked gas nor a coal-formed gas generated from the Upper Permian Longtan Formation source rock, instead it is a kerogen-cracked gas generated at the late stage from the Middle Devonian argilla- ceous source rock. The crude oil in paleo-oil reservoirs completely cracked into pyrobitumen and methane gas by the agency of hugely thick Triassic deposits. After that, the abnormal high pressure of methane gas reservoirs was completely destroyed due to the erosion of 2000--4500-m-thick Triassic strata. But the kerogen-cracked gas with normal pressure was preserved under the relatively sealed condition and became the main body of the gas shows.
基金supported by the National Natural Science Foundation of China (No. 40372068)
文摘A fluid inclusion fluorescence and microthermometric study was performed on sandstones from the deep Es4 reservoir rocks of the Minfeng （民丰） sag, north of Dongying （东营） depression. Two types of oil inclusions （yellow and blue white fluorescence）, one type of gas inclusions （blue white fluorescence）, and bitumen inclusions （no fluorescence） were detected within quartz and feldspar minerals. The evolution of hydrocarbon fluid inclusions in the lower Es4 sequence indicates that present oil accumulation was predominantly thermal stress controlled. Homogenization temperatures of aqueous fluid inclusions coexisting with gas-bearing and bitumen-bearing fluid inclusions indicate that oil cracking occurred at temperatures up to 160 ℃, primary condensate or wet gas genera- tion occurred during 170-195℃. Oil has cracked into condensate or wet gas in the depth of 4 300- 4 410 m and dry gas and abundant pyrobitumen in the depth of more than 4 410 m in the geological history based on the fluid inclusion extrapolation. Secondary oil cracking is undergoing in present day when the depth of reservoir is more than 4 150 m whose temperature is the threshold temperature of oil cracking （160 ℃）. However, because of the consumption of oil in the first oil cracking process, it may have few chances to find liquid petroleum, and only natural gas can be found when the depth of reservoir is more than 4 410 m, where oil cracks into condensate gas or wet gas according to present-day formation temperature. This study is preliminary but foreshadows a new insight into oilcracking using natural fluid inclusions to trace hydrocarbon evolution in sedimentary basins.
基金financial support from the National Science and Technology Major Project of China(Grant No. 2008ZX05018)Taishan Scholar Constructive Engineering Foundation of Shandong province(No. ts20120518)
文摘A study of reaction mechanisms and chemical kinetics of pressurized pyrolysis of Chinese Liushuhe oil shale in the presence of water were conducted using an autoclave for simulating and modeling in-situ underground thermal degradation.It was found that the oil shale was first pyrolyzed to form pyrobitumen,shale oil,shale gas and residue,then the pyrobitumen was further pyrolyzed to form more shale oil,shale gas,and residue.It means that there are two consecutive and parallel reactions.With increasing temperature,the pyrobitumen yield,as intermediate,first reached a maximum,then decreased to approximately zero.The kinetics results show that both these reactions are first order.The activation energy of pyrobitumen formation from oil shale is lower than that of shale oil formation from pyrobitumen.
基金funded by the National Natural Science Foundation of China for Young Scholars(No.41903059).
文摘The Neoproterozoic-Lower Paleozoic dolostone gas reservoirs in the Chuanzhong Uplift in Southwestern China contain the mesophase pyrobitumen (pyrobitumen with mesophase). The mesophase in the pyrobitumen is mostly composed of a mixture of condensed macromolecule polycyclic aromatic hydrocarbons (PAH), and has been mostly converted to various grain, flow, and domain textures. The volcanic activity nearby the Chuanzhong Uplift may have generated very hot (over 300 °C) hydrothermal fluid, with migration of the fluid into the dolostone reservoir transforming the hydrocarbons in the reservoir into an anisotropic carbon by-product, which formed under high temperature and pressure conditions;over 300 °C and 200 MPa according to fluid inclusion analysis. The high temperature-pressure in reservoir was caused by sudden devolatilization of the hydrocarbons due to hydrothermal heating, which formed the unusual texture of the mesophase. The elliptical mesophase grains (EG), the honeycomb structure of pyrobitumen, and the occurrence of polarized classes of mesophase in single pyrobitumen deposits are all unusual textures. This study investigates the texture development of this pressure-affected pyrobitumen. Observation and study of the mesophase suggest that the class of mesophase in pyrobitumen is determined by temperature, while pressure (assessed from associated fluid inclusions) significantly affected the texture. Analysis of the texture of the pyrobitumen in conjunction with previous thermometry results from methane inclusions suggests that the high class mesophase of the pyrobitumen could be applied as a temperature indicator for geological conditions. Furthermore, the unusual textures of the pyrobitumen including elliptical mesophase grains (EG), the honeycomb structure of pyrobitumen, and the occurrence of polarized classes of mesophase in single pyrobitumen could reflect the abnormal high formation pressure.
基金supported by the National Natural Science Foundation of China(Grant Nos.42230808 and 41830425).
文摘Maturity evaluation of highly evolved organic matter is an important problem in oil and gas geochemistry,because conventional organic geochemical proxies are not applicable due to hydrocarbon generation and expulsion.In this study,we investigated the pyrobitumen in the reservoirs of the Sinian Dengying Formation in the Sichuan Basin,China.We focused on aromatic hydrocarbon biomarkers,and the calibration and application of aromatic maturity proxies using pyrobitumen reflectance and Raman spectral parameters.Our results show that only the thiophene compounds are effective maturity indicators,such as MDR(4-/1-MDBT),MDR′(4-MDBT/(1-MDBT+4-MDBT)),MDR1(1-MDBT/DBT),4,6-/(1,4+1,6)-DMDBT,(2,6+3,6)-/(1,4+1,6)-DMDBT,and[2,1]BNT/([2,1]BNT+[1,2]BNT),as these are largely independent of the optical anisotropy of pyrobitumen.The condensation and incorporation of thiophene compounds can lead to an increase in the reflectance of pyrobitumen,which means the thiophene compound parameters are positively or negatively correlated with pyrobitumen reflectance.New potential maturity parameters were proposed,including DMDBTs/MDBTs,TeMDBTs/(DBT+MDBTs+DMDBTs+TMDBTs+TeMDBTs),1-MDBT/MDBTs,and[2,1]BNT/BNTs.This method and these parameters are universally applicable to maturity characterization,especially in rocks that lack vitrinite,contain strongly anisotropic organic matter,and have high contents of thiophene compounds.
基金Open access funding provided by University of Miskolc.“Improved exploitation and utilization of subsurface natural resources”(TUDFO/51757–1/2019-ITM)Thematic Excellence Program of the University of Miskolc,financed by the National Research,Development and Innovation Office of Hungary+1 种基金Sustainable Raw Materials Management Thematic Network—RING 2017,EFOP-3.6.2–2017-00010 project in the framework of the Széchenyi 2020 Programsupported by the European Union,co-financed by the European Social Fund.
文摘The paper comprises new analytical data on the nature and occurrence of gold in solid pyrobitumen,closely associated with the main gold-bearing sulfide arsenic ores of the Bakyrchik gold deposit(Kazakhstan),related to post-collisional magmatic-hydrothermal origin.Gold mineralization of the deposit occurs mainly in the form of an“invisible”type of gold in the structures of arsenian pyrite and arsenopyrite,and the form of gold-organic compounds of pyrobitumen in carbonaceous-terrigenous sequences of Carboniferous formation.Microscopic and electron microscopic analysis,Raman and FT-Infrared analysis,mineralogical and three-step sequential extraction analysis(NH2OHHCl,H2O2,HNO3?HCl)has been carried out using 9 ore samples(from 3 different types of ores)for a comprehensive study of pyrobitumen and sulfide arsenic ores focusing mainly on organic matter.The sequentially extracted precious metal content of pyrobitumen reaches up to 7 ppm gold and other metals like Ag 4 ppm,Pt 31 ppb,and Pd 26 ppb,forming metal–organic compounds,while arsenic sulfide minerals incorporate 11 ppm gold,39 ppm Ag,0.49 ppm Pt.The enrichment of gold associating with organic matter and sulfide ore minerals was confirmed in this study.Organic matter was active in the migration of gold and the capture of gold by pyrobitumen.Moreover,the reductive organic matter agent released gold,most likely for the sulfide arsenic ore minerals.Pyrobitumen was a decisive factor in the concentration,transportation,and preservation of gold in the deposit.
