FTT experiments with water as a hydrogen source and three types of possible carbon sources in the subsurface(diiron nonacarbonyl,siderite and formic acid,representing CO,CO_(2)and a simple organic acid,respectively)we...FTT experiments with water as a hydrogen source and three types of possible carbon sources in the subsurface(diiron nonacarbonyl,siderite and formic acid,representing CO,CO_(2)and a simple organic acid,respectively)were carried out in this study.Our experimental results showed that n-alkanes with the highest carbon number of C_(33)were produced when CO was used as a carbon source(series A);a variety of polycyclic aromatic hydrocarbons(PAHs)were detected in series B with CO_(2)as a carbon source;gaseous hydrocarbons were also detected with formic acid added(series C).The different products in the three series showed that there were different hydrocarbon generation mechanisms and reaction processes with different carbon sources.The generation of long-chain n-alkanes in series A provided experimental support for the formation of abiogenic petroleum underground,which was of significance to early membranes on the Earth.PAHs in series B provide experimental support for the possibility of an abiotic source of reduced carbon on other planets.The carbon isotopes of gaseous hydrocarbons produced by CO exhibited a partial reversed order(δ^(13)C_(1)<δ^(13)C_(2)>δ^(13)C_(3)>δ^(13)C_(4)>δ^(13)C_(5)),while the gaseous hydrocarbons produced by CO_(2)and HCOOH showed a positive order(δ^(13)C_(1)<δ^(13)C_(2)<δ^(13)C_(3)<δ^(13)C_(4)<δ^(13)C_(5)).Based on these,the alkylene mechanism and the carbonyl insertion mechanism were used to reasonably explain these characteristics.展开更多
工程微震监测中常包含较多低信噪比信号。现有去噪方法存在参数多且需要手工调节等问题,为此,提出一种针对微震信号的无参数自动去噪PD(pick and denoise)算法。算法首先通过改进AIC(akaike information criterion)方法初步拾取P波初至...工程微震监测中常包含较多低信噪比信号。现有去噪方法存在参数多且需要手工调节等问题,为此,提出一种针对微震信号的无参数自动去噪PD(pick and denoise)算法。算法首先通过改进AIC(akaike information criterion)方法初步拾取P波初至,得到信号的背景噪声段,通过傅里叶变换在频率域上提取噪声功率谱信息,在此基础上从微震信号的功率谱中减去噪声功率谱,最后应用傅里叶逆变换还原得到去噪后微震信号。利用Matlab人工合成不同类型、不同信噪比的含噪信号,应用PD算法进行去噪并与EEMD(ensemble empirical mode decomposition)、小波去噪方法进行比较,结果表明:PD算法去噪后的平均绝对误差和误差标准差均优于EEMD和小波去噪方法,并且对于低信噪比信号,PD算法仍具有良好的效果。最后将PD算法应用于陕西省引汉济渭工程秦岭4#支洞微震监测工程中,对2730条微震信号进行去噪分析,得平均P波信噪比从滤波前的16.49提高到了35.62,表明PD算法对于提高工程微震信号质量具有良好的应用价值。展开更多
The peculiarities of lipids in lacustrine core sediments from Fildes Peninsula, King George Island, Antarctica, are reported. The origin of high-molecular-weight n-alkanes, alkenes, fatty acids, alcohols is supposed t...The peculiarities of lipids in lacustrine core sediments from Fildes Peninsula, King George Island, Antarctica, are reported. The origin of high-molecular-weight n-alkanes, alkenes, fatty acids, alcohols is supposed to be related to the abundant moss occurring in the sediments. Abundant iso- and ante/so-fatty acids that occur in the sediments indicate a relatively strong bacterial activity in non-ice-cover zone than in other regions in Antarctica. The C18:2 unsaturated fatty acids mainly originate from autochthonous algae in the sediment pool, and the C18:2/C18:0 ratios in the profile are controlled more by paleotemperatures than source assemblies. Long-chain alkenones were identified in freshwater lacustrine sediment in Antarctica for the first time, of which Prymnesiophyceae is assumed to be the source organism. High relative abundance of C37:4 homologue in long-chain alkenone well correlates to the severely cold climate in Antarctica.展开更多
The present paper studies the mineralogy and geochemistry of a geological section in Jianghan basin. Widely distributed immature oils in this basin have been shown to relate to the carbonate depositional stage of salt...The present paper studies the mineralogy and geochemistry of a geological section in Jianghan basin. Widely distributed immature oils in this basin have been shown to relate to the carbonate depositional stage of salt lake sedimentation cycle. It is concluded that only when the content of organic carbon in the rocks is taken into account, is it meaningful to calculate the immature oil in the source rocks.展开更多
Hydrocarbons, include heavy oils, normal oils, waxy oils and light oils, condensate oils and gases were all found in Lunnan Oilfield, the occurrences of hydrocarbons with complicated physical properties indicates a co...Hydrocarbons, include heavy oils, normal oils, waxy oils and light oils, condensate oils and gases were all found in Lunnan Oilfield, the occurrences of hydrocarbons with complicated physical properties indicates a complicated distribution of reservoirs. By the drilling data, the distribution pattern had been found that, in plan view, the density of crude oils in the western part is heavier than that of oils in the eastern part in Lunnan region, namely the crude oils were mainly found in the western part while the natural gases were mainly found in the eastern, which shows that an obvious differentiation in the east and west part was presented in the Lunnan region. Furthermore, in vertical view, the light hydrocarbons were mainly found in the Carboniferous reservoir while the heavier hydrocarbons were mainly found in the Ordovician and Triassic reservoirs. By analysis of the semi-logarithm distribution of n-alkanes, biomarker ratios and stable carbon isotopic compositions of crude oils, we have found展开更多
To date, questions remain as to how to differentiate between coal- and interbedded shale-sourced oils in coal measures. Based on the hypothesis that δ13C value of sedimentary organic matter is controlled by the depos...To date, questions remain as to how to differentiate between coal- and interbedded shale-sourced oils in coal measures. Based on the hypothesis that δ13C value of sedimentary organic matter is controlled by the depositional environment and productivities of biota grown in such depositional setting, this note examines compound specific carbon isotopic profiles from coal and interbedded shale extracts using the gas chromatography-isotope ratio mass spec-trometry technique (GC/IRMS). The results show that compound specific carbon isotope values from coal extracts are enriched in 13C relative to that of interbedded shale extracts, and provide useful information in characterizing coal- and interbedded shale-sourced oils in coal measures. An example for its successful application from the Turpan Basin, Northwestern China is presented.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
Gold reactor pyrolysis system is used to model the gas formation from the Upper Paleozoic coal measures and the results show coal-derived gas characterized with δ13C1 of-33.46‰, δ13C2 of-23.1‰, dryness(C1/C1-4) 85...Gold reactor pyrolysis system is used to model the gas formation from the Upper Paleozoic coal measures and the results show coal-derived gas characterized with δ13C1 of-33.46‰, δ13C2 of-23.1‰, dryness(C1/C1-4) 85.6%. And then, effects of the post-genetic processes on coal- derived gas are analyzed in turn: (i) About 27% coal-derived gases constituted with more methane are calculated to be lost during diffusion. The residual in reservoir are characterized with almost the same compositions as the original, which suggests faint influence by diffusion (the residual, δ13C1 of -32.78‰, δ13C2 of-23.1‰, C1/C1-4 83%); (ii) Water washing made about 8% coal-formed gases lost and their components and stable carbon isotopes are stable; (iii) In the final, it is speculated that primary migration makes much more wet gas (C2-4) leave in coal measures. The variance of gas dryness induced by this factor is estimated to be about 10%.展开更多
The molecular compositions and molecular carbon isotopic compositions of gas hydrocarbons produced in the hydrocarbon generation of oil asphaltene from Lunnnan area were investigated by pyrolysis of asphaltene sealed ...The molecular compositions and molecular carbon isotopic compositions of gas hydrocarbons produced in the hydrocarbon generation of oil asphaltene from Lunnnan area were investigated by pyrolysis of asphaltene sealed in gold tube in a limited system. The experimental results indicated that oil asphaltene from Lunnan area had relatively high generation potential of methane. However, the molecular compositions and molecular carbon isotopic compositions of gas hydrocarbons in the hydrocarbon generation of oil asphaltene exhibited different characteristics from that of gas hydrocarbons by primary cracking of kerogen and secondary cracking of oil. Based on kinetic simulation with paleo-geothermal data of oil reservoir, the methane produced by cracking of oil asphatene was characterized by relatively light carbon isotopic compositions. This result could not explain relatively heavy carbon isotopic compositions of natural gas from Lunnan area. Pyrolysis of kerogen from source rocks under very high temperature展开更多
Sulfur plays an important role in the generation and evolution of hydrocarbon from organic matter. Here, a pyrolysis experiment in closed system was performed on Maoming oil shales kerogen (Type Ⅰ), Maoming oil shale...Sulfur plays an important role in the generation and evolution of hydrocarbon from organic matter. Here, a pyrolysis experiment in closed system was performed on Maoming oil shales kerogen (Type Ⅰ), Maoming oil shales kerogen added with sulfur ether and Maoming oil shales kerogen added with sulphur. The results suggest that the existence of sulfur can result in: (i) higher yield of hydrocarbons generated from the kerogen; (ii) decrease of the temperature for the maximum generation of heavy hydrocarbons (the C15+ fraction) by 20℃; (iii) decrease of the temperature for the maximum generation of the aromatics fraction by 40℃, and (iv) acceleration of the aromatization process. The pyrolysates from kerogen added with sulfur are similar to the heating products of the sulfur-rich kerogen as reported in the literatures. It seems that the sulfur catalysis is also an important factor that can make the sulfur-rich kerogen generate low-mature oil at the earlier diagenesis stage, except for the weakness of the C-展开更多
Secondary variation of reservoir is a hot problem in petroleum geochemistry field. Several kinds of secondary variations have taken place after the formation of bituminous sandstones in the Tarim Basin including biode...Secondary variation of reservoir is a hot problem in petroleum geochemistry field. Several kinds of secondary variations have taken place after the formation of bituminous sandstones in the Tarim Basin including biodegra-dation, washing, dissipation and secondary thermal stress. Biodegraded bituminous sandstones were used in the experiment. Pyrolysis experiment has been performed in a closed system, simulating secondary thermal stress with continual burial of Silurian bituminous sandstones which may cause the changes in molecular compositions, carbon isotope and physical properties of bituminous sandstones. The results are as follows: (i) Gases are mainly product during the experiment and carbon isotope of gas is lighter. (ii) Yield of C6+ hydrocarbon is relative smaller, and yielded oil is mainly light oil. (iii) Chromatogram character of biodegraded oil-sand is similar to that of saturated hydrocarbon in extracts from present-day bituminous sandstones, (iv) Porosity of bituminous sandstones gradually展开更多
One monoaromatic tricyclic diterpane and two aromatic tricyclic diterpanes were found in three low-maturity source rocks and five crude oils of the Tertiary Shahejie Formation in Shengli Oil Field. The compounds found...One monoaromatic tricyclic diterpane and two aromatic tricyclic diterpanes were found in three low-maturity source rocks and five crude oils of the Tertiary Shahejie Formation in Shengli Oil Field. The compounds found include C19H28 (m/z 145, M+ 256) ring-C monoaromatic tricyclic terpane, C17H20 (m/z 209, M+ 224) and C18H22 (m/z 223,M+ 238) rings-B,C diaromatic diterpanes. The results show that these compounds are biomarkers of immature organic matter with a stability sequence of C18H22 】 C17H20 】 C19H28. The cleavage of ring-D of pentacyclic triterpanoids, such as oleanene, hopene, fernene, ursene, in the early stage of diagenesis may be one of the origin pathways of rings-B, C diaromatic tricyclic diterpanes.展开更多
基金funded by a grant from the National Key R&D Program of China(Grant No.2017YFC0603102)partially supported by the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDA14010102)a Chinese NSF grant(Grant No.41973069)。
文摘FTT experiments with water as a hydrogen source and three types of possible carbon sources in the subsurface(diiron nonacarbonyl,siderite and formic acid,representing CO,CO_(2)and a simple organic acid,respectively)were carried out in this study.Our experimental results showed that n-alkanes with the highest carbon number of C_(33)were produced when CO was used as a carbon source(series A);a variety of polycyclic aromatic hydrocarbons(PAHs)were detected in series B with CO_(2)as a carbon source;gaseous hydrocarbons were also detected with formic acid added(series C).The different products in the three series showed that there were different hydrocarbon generation mechanisms and reaction processes with different carbon sources.The generation of long-chain n-alkanes in series A provided experimental support for the formation of abiogenic petroleum underground,which was of significance to early membranes on the Earth.PAHs in series B provide experimental support for the possibility of an abiotic source of reduced carbon on other planets.The carbon isotopes of gaseous hydrocarbons produced by CO exhibited a partial reversed order(δ^(13)C_(1)<δ^(13)C_(2)>δ^(13)C_(3)>δ^(13)C_(4)>δ^(13)C_(5)),while the gaseous hydrocarbons produced by CO_(2)and HCOOH showed a positive order(δ^(13)C_(1)<δ^(13)C_(2)<δ^(13)C_(3)<δ^(13)C_(4)<δ^(13)C_(5)).Based on these,the alkylene mechanism and the carbonyl insertion mechanism were used to reasonably explain these characteristics.
文摘工程微震监测中常包含较多低信噪比信号。现有去噪方法存在参数多且需要手工调节等问题,为此,提出一种针对微震信号的无参数自动去噪PD(pick and denoise)算法。算法首先通过改进AIC(akaike information criterion)方法初步拾取P波初至,得到信号的背景噪声段,通过傅里叶变换在频率域上提取噪声功率谱信息,在此基础上从微震信号的功率谱中减去噪声功率谱,最后应用傅里叶逆变换还原得到去噪后微震信号。利用Matlab人工合成不同类型、不同信噪比的含噪信号,应用PD算法进行去噪并与EEMD(ensemble empirical mode decomposition)、小波去噪方法进行比较,结果表明:PD算法去噪后的平均绝对误差和误差标准差均优于EEMD和小波去噪方法,并且对于低信噪比信号,PD算法仍具有良好的效果。最后将PD算法应用于陕西省引汉济渭工程秦岭4#支洞微震监测工程中,对2730条微震信号进行去噪分析,得平均P波信噪比从滤波前的16.49提高到了35.62,表明PD算法对于提高工程微震信号质量具有良好的应用价值。
文摘The peculiarities of lipids in lacustrine core sediments from Fildes Peninsula, King George Island, Antarctica, are reported. The origin of high-molecular-weight n-alkanes, alkenes, fatty acids, alcohols is supposed to be related to the abundant moss occurring in the sediments. Abundant iso- and ante/so-fatty acids that occur in the sediments indicate a relatively strong bacterial activity in non-ice-cover zone than in other regions in Antarctica. The C18:2 unsaturated fatty acids mainly originate from autochthonous algae in the sediment pool, and the C18:2/C18:0 ratios in the profile are controlled more by paleotemperatures than source assemblies. Long-chain alkenones were identified in freshwater lacustrine sediment in Antarctica for the first time, of which Prymnesiophyceae is assumed to be the source organism. High relative abundance of C37:4 homologue in long-chain alkenone well correlates to the severely cold climate in Antarctica.
文摘The present paper studies the mineralogy and geochemistry of a geological section in Jianghan basin. Widely distributed immature oils in this basin have been shown to relate to the carbonate depositional stage of salt lake sedimentation cycle. It is concluded that only when the content of organic carbon in the rocks is taken into account, is it meaningful to calculate the immature oil in the source rocks.
文摘Hydrocarbons, include heavy oils, normal oils, waxy oils and light oils, condensate oils and gases were all found in Lunnan Oilfield, the occurrences of hydrocarbons with complicated physical properties indicates a complicated distribution of reservoirs. By the drilling data, the distribution pattern had been found that, in plan view, the density of crude oils in the western part is heavier than that of oils in the eastern part in Lunnan region, namely the crude oils were mainly found in the western part while the natural gases were mainly found in the eastern, which shows that an obvious differentiation in the east and west part was presented in the Lunnan region. Furthermore, in vertical view, the light hydrocarbons were mainly found in the Carboniferous reservoir while the heavier hydrocarbons were mainly found in the Ordovician and Triassic reservoirs. By analysis of the semi-logarithm distribution of n-alkanes, biomarker ratios and stable carbon isotopic compositions of crude oils, we have found
基金This work was supported by the Chinese Academy of Sciences (Grant No. KZ951-B1-412).
文摘To date, questions remain as to how to differentiate between coal- and interbedded shale-sourced oils in coal measures. Based on the hypothesis that δ13C value of sedimentary organic matter is controlled by the depositional environment and productivities of biota grown in such depositional setting, this note examines compound specific carbon isotopic profiles from coal and interbedded shale extracts using the gas chromatography-isotope ratio mass spec-trometry technique (GC/IRMS). The results show that compound specific carbon isotope values from coal extracts are enriched in 13C relative to that of interbedded shale extracts, and provide useful information in characterizing coal- and interbedded shale-sourced oils in coal measures. An example for its successful application from the Turpan Basin, Northwestern China is presented.
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
文摘Gold reactor pyrolysis system is used to model the gas formation from the Upper Paleozoic coal measures and the results show coal-derived gas characterized with δ13C1 of-33.46‰, δ13C2 of-23.1‰, dryness(C1/C1-4) 85.6%. And then, effects of the post-genetic processes on coal- derived gas are analyzed in turn: (i) About 27% coal-derived gases constituted with more methane are calculated to be lost during diffusion. The residual in reservoir are characterized with almost the same compositions as the original, which suggests faint influence by diffusion (the residual, δ13C1 of -32.78‰, δ13C2 of-23.1‰, C1/C1-4 83%); (ii) Water washing made about 8% coal-formed gases lost and their components and stable carbon isotopes are stable; (iii) In the final, it is speculated that primary migration makes much more wet gas (C2-4) leave in coal measures. The variance of gas dryness induced by this factor is estimated to be about 10%.
文摘The molecular compositions and molecular carbon isotopic compositions of gas hydrocarbons produced in the hydrocarbon generation of oil asphaltene from Lunnnan area were investigated by pyrolysis of asphaltene sealed in gold tube in a limited system. The experimental results indicated that oil asphaltene from Lunnan area had relatively high generation potential of methane. However, the molecular compositions and molecular carbon isotopic compositions of gas hydrocarbons in the hydrocarbon generation of oil asphaltene exhibited different characteristics from that of gas hydrocarbons by primary cracking of kerogen and secondary cracking of oil. Based on kinetic simulation with paleo-geothermal data of oil reservoir, the methane produced by cracking of oil asphatene was characterized by relatively light carbon isotopic compositions. This result could not explain relatively heavy carbon isotopic compositions of natural gas from Lunnan area. Pyrolysis of kerogen from source rocks under very high temperature
文摘Sulfur plays an important role in the generation and evolution of hydrocarbon from organic matter. Here, a pyrolysis experiment in closed system was performed on Maoming oil shales kerogen (Type Ⅰ), Maoming oil shales kerogen added with sulfur ether and Maoming oil shales kerogen added with sulphur. The results suggest that the existence of sulfur can result in: (i) higher yield of hydrocarbons generated from the kerogen; (ii) decrease of the temperature for the maximum generation of heavy hydrocarbons (the C15+ fraction) by 20℃; (iii) decrease of the temperature for the maximum generation of the aromatics fraction by 40℃, and (iv) acceleration of the aromatization process. The pyrolysates from kerogen added with sulfur are similar to the heating products of the sulfur-rich kerogen as reported in the literatures. It seems that the sulfur catalysis is also an important factor that can make the sulfur-rich kerogen generate low-mature oil at the earlier diagenesis stage, except for the weakness of the C-
文摘Secondary variation of reservoir is a hot problem in petroleum geochemistry field. Several kinds of secondary variations have taken place after the formation of bituminous sandstones in the Tarim Basin including biodegra-dation, washing, dissipation and secondary thermal stress. Biodegraded bituminous sandstones were used in the experiment. Pyrolysis experiment has been performed in a closed system, simulating secondary thermal stress with continual burial of Silurian bituminous sandstones which may cause the changes in molecular compositions, carbon isotope and physical properties of bituminous sandstones. The results are as follows: (i) Gases are mainly product during the experiment and carbon isotope of gas is lighter. (ii) Yield of C6+ hydrocarbon is relative smaller, and yielded oil is mainly light oil. (iii) Chromatogram character of biodegraded oil-sand is similar to that of saturated hydrocarbon in extracts from present-day bituminous sandstones, (iv) Porosity of bituminous sandstones gradually
文摘One monoaromatic tricyclic diterpane and two aromatic tricyclic diterpanes were found in three low-maturity source rocks and five crude oils of the Tertiary Shahejie Formation in Shengli Oil Field. The compounds found include C19H28 (m/z 145, M+ 256) ring-C monoaromatic tricyclic terpane, C17H20 (m/z 209, M+ 224) and C18H22 (m/z 223,M+ 238) rings-B,C diaromatic diterpanes. The results show that these compounds are biomarkers of immature organic matter with a stability sequence of C18H22 】 C17H20 】 C19H28. The cleavage of ring-D of pentacyclic triterpanoids, such as oleanene, hopene, fernene, ursene, in the early stage of diagenesis may be one of the origin pathways of rings-B, C diaromatic tricyclic diterpanes.
