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Yunyan Ni - One of the best experts on this subject based on the ideXlab platform.
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Genetic types of gas hydrates in China
Petroleum Exploration and Development, 2017Co-Authors: Yunyan Ni, Shipeng Huang, Weilong Peng, Deyu GongAbstract:Abstract Researches were carried out on the origin of gas hydrate samples from the tundra in the Qilian Mountain, Pearl River Mouth Basin in the northern South Sea and the continental slope of Taixinan Basin in China. Gases of the gas hydrate samples from the Jurassic Jiangcang Formation in the Muli County in Qilian Mountain are mainly of oil-Derived origin, characterized by self-generation and self-preservation. δ13C1 values range from −52.7‰ to −35.8‰, and the δ13C2 values vary from −42.3‰ to −29.4‰. There was a small amount of Coal-Derived Gases, which might source from the Coal-bearing Middle-Jurassic Muli Formation with δ13C1 of −35.7‰ – −31.3‰ and δ13C2 of −27.5‰ – −25.7‰. Gases of the gas hydrate samples from the Pearl River Mouth Basin and Taixinan Basin are dominated by bacterial origin of carbonate reduction, with δ13C1 of −74.3‰ – −56.7‰ and δD1 of −226‰ – −180‰. A trace amount of thermogenic Gases were also found in these basins with δ13C1 of −54.1‰ – −46.2‰. This study combined the geochemical data of gas hydrates from 20 areas (basins) in the world, and concluded that thermogenic Gases of the gas hydrates in the world can be either of Coal-Derived or oil-Derived origin, but dominated by oil-Derived origin. A small amount of Coal-Derived gas was also found in the Qilian Mountain in China and the Vancouver Island in Canada. The Coal-Derived gas has relatively heavy δ13C1 ≥ −45‰ and δ13C2 > −28‰, while the oil-Derived gas has δ13C1 from −53‰ – −35‰ and δ13C2
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stable hydrogen and carbon isotopic ratios of Coal Derived Gases from the turpan hami basin nw china
International Journal of Coal Geology, 2015Co-Authors: Yunyan Ni, Deyu Gong, Dijia Zhang, Fengrong Liao, Fei Yu, Jingzhi Yu, Jianping Chen, Changyi Zhao, Jian HuAbstract:Abstract Natural Gases from the Qiudong and Hongtai gas fields in the Taibei sag in the Turpan-Hami Basin of China were analyzed for stable hydrogen and carbon isotopic characteristics, to investigate the origin of the gas and the gas-source correlation. Natural Gases from the two gas fields are dominated by alkane Gases with methane content varying from 81.61% to 92.57%. Dryness ranges from 0.76 to 0.93, indicating an abundance of wet gas. The carbon and hydrogen isotopic compositions of the methane vary from − 39.8‰ to − 42.6‰ and from − 263‰ to − 279‰ in the Qiudong gas field, respectively, and from − 37.7‰ to − 39.0‰ and from − 250‰ to − 257‰ in the Hongtai gas field, respectively. All Gases have a characteristic carbon and hydrogen isotopic distribution pattern among the C1–C5 alkanes, in which δ13CCH4
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stable carbon isotopes of Coal Derived Gases sourced from the mesozoic Coal measures in china
Organic Geochemistry, 2014Co-Authors: Deyu Gong, Yunyan Ni, Shipeng Huang, Wei WuAbstract:Coal-Derived, large scale gas fields Derived from the Mesozoic Coal measures in China are mainly distributed in the Middle–Lower Jurassic Coal measures in the Tarim, Junggar and Turpan-Hami basins in northwest China, and the Upper Triassic Xujiahe Formation Coal measure in Sichuan Basin, central China. In 2011, the annual production was 21.6 × 109 m3 and the proved geological reserves were 2485 × 109 m3, accounting for 21% and 30% of the total in China, respectively. Based on analyses of gas composition and stable carbon isotopes ratios of 203 samples and stable carbon isotopes of 102 CO2 samples, the following conclusions were made. (a) Based on diagnostic plots using the stable carbon isotopic and molecular composition of gas samples, alkane gas from the Mesozoic Coal measures in China is shown to be Coal-Derived. (b) According to the δ13C2 vs. C2H6 plot of a great number of oil-Derived and Coal-Derived Gases in China, it is concluded that Gases with δ13C2 > −28.5‰ are Coal-Derived and those with δ13C2 < −28.5‰ are oil-Derived in most cases. (c) Among the natural Gases from the Mesozoic Coal measures in China, primary Coal-Derived Gases with normal carbon isotopic distribution pattern among the C1–C4 alkanes (i.e. δ13C1 < δ13C2 < δ13C3 < δ13C4) are dominant. (d) Carbon isotopic pattern reversal mainly results from the mixing of Coal-Derived Gases having different maturities but the same source and secondly from microbial oxidation of propane (e.g. Mu 3 and Mu 4 wells in the Gumudi gas field, Junggar Basin). (e) CO2 in the Coal-Derived Gases from the Mesozoic Coal measures in China has both biogenic and abiogenic origins. The biogenic origin is dominant and the abiogenic CO2 is mainly found in the Kuqa Depression in the Tarim Basin and western Sichuan Basin. (f) Isotopic differences between heavy hydrocarbon Gases and methane become less with increasing maturity.
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stable hydrogen and carbon isotopic ratios of Coal Derived and oil Derived Gases a case study in the tarim basin nw china
International Journal of Coal Geology, 2013Co-Authors: Yunyan Ni, Wei Wu, Dijia Zhang, Fengrong Liao, Shuichang Zhang, Jin Su, Deyu GongAbstract:Abstract Natural Gases from the Kuqa depression, Lunnan and Tazhong low uplifts in the Tarim basin of China were analyzed for stable hydrogen and carbon isotopic characteristics, to compare the isotopic differences, particularly of hydrogen, between Coal-Derived and oil-Derived Gases. Gases from the Kuqa depression are Coal-Derived and sourced from Middle–Lower Jurassic Coal measures, possibly with a minor contribution from Triassic lacustrine mudstones. Gases from the Lunnan and Tazhong low uplifts are thought to be sourced from Cambrian–Lower Ordovician marine sapropelic organic matter. Natural Gases from the Lunnan low uplift and Ordovician strata in the Tazhong low uplift are oil-cracked, and Gases from the Carboniferous and Silurian strata in the Tazhong low uplift are oil-associated. Most Gases have expected hydrogen isotopic distributions among C 1 –C 3 alkanes, i.e., δ 2 H CH4 2 H C2H6 2 H C3H8 . However, nearly all samples that show carbon isotopic reversal between C 1 and C 2 alkanes (δ 13 C CH4 > δ 13 C C2H6 ) in the Lunnan low uplift also have corresponding hydrogen isotopic reversal (δ 2 H CH4 > δ 2 H C2H6 ) between these alkanes. In the Tazhong low uplift, except for the Silurian Gases, nearly all the Carboniferous and Ordovician Gases have regular carbon isotopic distribution pattern among C 1 –C 2 alkanes (δ 13 C CH4 13 C C2H6 ) but with hydrogen isotopic reversal between C 1 and C 2 alkanes (δ 2 H CH4 > δ 2 H C2H6 ). This probably indicates that except the influences of mixing with Gases at different maturity, hydrogen isotopes of natural Gases are also sensitive to other processes such as hydrogen exchange between water and organic matter during thermal maturation. No analytical differences in δ 2 H CH4 have been found between Coal-Derived Gases sourced from continental humic organic matter in the Kuqa depression and the oil-Derived Gases sourced from the Carboniferous and Silurian marine sapropelic organic matter in the Tazhong low uplift. All Coal-Derived Gases in the Kuqa depression have δ 2 H CH4 values less than − 150‰, while the oil-cracked Gases in the Lunnan low uplift and the Ordovician oil-cracked Gases in the Tazhong low uplift have slightly greater δ 2 H CH4 values (>− 150‰). However, the Silurian and Carboniferous oil-associated Gases in the Tazhong low uplift also have quite low δ 2 H CH4 values (around − 160‰). The clearly different hydrogen isotopic values of Gases from different strata in the Tazhong low uplift and the close hydrogen isotopic values between Gases from the Kuqa depression and Silurian and Carboniferous strata in the Tazhong low uplift, all imply that hydrogen isotopes of alkane Gases are influenced by factors more than thermal maturity and depositional environments. Great care needs to be paid when using the hydrogen isotopes for gas genetic study, and a combination with local geological settings and other geochemical features is suggested. This is because hydrogen isotopes of alkane Gases in one basin may be not applicable in the other basins.
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Discussion on the gas source of the Triassic Xujiahe Formation tight sandstone gas reservoirs in Yuanba and Tongnanba, Sichuan Basin: An answer to Yin Feng et al.
Petroleum Exploration and Development, 2013Co-Authors: Fengrong Liao, Yunyan NiAbstract:Abstract Gas-source correlation is generally focused on the genetic type of the main gas components, dominantly oil-associated gas or Coal-Derived gas. Gases from the Yuanba and Tongnanba gas reservoirs are dominated by methane with an average content of 95.36%. The average contents of ethane, propane, butane are 1.60%, 0.29% and 0.09%, respectively. In general, for the Yuanba and Tongnanba gas reservoirs, alkane gas has an average content of 97.34%, and CO 2 has an average content of 0.63%, which only accounts for 6.5‰ of the methane. According to the discrimination criteria that δ 13 C 2 value is greater than −28‰ for Coal-Derived gas and lower than −28.5‰ for the oil-associated gas, Yin et al. suggested that the Gases from the Yuanba gas reservoir be a mixture of Coal-Derived and oil-associated Gases, and the Gases from the Tongnanba gas reservoir be oil-associated gas. However, the discrimination criteria of δ 13 C 2 for Coal-Derived and oil-associated Gases are only valid when the alkane Gases have not undergone secondary alteration and have positive carbon isotopic series among C 1 –C 4 alkanes. Hence, it is concluded that Gases from the Yuanba and Tongnanba gas reservoirs are Coal-Derived Gases due to their high content and heavy carbon isotopic values of methane (−31.3‰), which is typical for high mature Coal-Derived Gases in the world. Though Yin et al. suggested that abiogenic CO 2 of these two reservoirs is originated from metamorphism or hydrolysis of deep carbonate rocks, we proposed that these CO 2 Gases are self-generated and self-accumulated under the corrosion of calcarenaceous sandstone of the Triassic Xujiahe Formation.
Deyu Gong - One of the best experts on this subject based on the ideXlab platform.
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Genetic types of gas hydrates in China
Petroleum Exploration and Development, 2017Co-Authors: Yunyan Ni, Shipeng Huang, Weilong Peng, Deyu GongAbstract:Abstract Researches were carried out on the origin of gas hydrate samples from the tundra in the Qilian Mountain, Pearl River Mouth Basin in the northern South Sea and the continental slope of Taixinan Basin in China. Gases of the gas hydrate samples from the Jurassic Jiangcang Formation in the Muli County in Qilian Mountain are mainly of oil-Derived origin, characterized by self-generation and self-preservation. δ13C1 values range from −52.7‰ to −35.8‰, and the δ13C2 values vary from −42.3‰ to −29.4‰. There was a small amount of Coal-Derived Gases, which might source from the Coal-bearing Middle-Jurassic Muli Formation with δ13C1 of −35.7‰ – −31.3‰ and δ13C2 of −27.5‰ – −25.7‰. Gases of the gas hydrate samples from the Pearl River Mouth Basin and Taixinan Basin are dominated by bacterial origin of carbonate reduction, with δ13C1 of −74.3‰ – −56.7‰ and δD1 of −226‰ – −180‰. A trace amount of thermogenic Gases were also found in these basins with δ13C1 of −54.1‰ – −46.2‰. This study combined the geochemical data of gas hydrates from 20 areas (basins) in the world, and concluded that thermogenic Gases of the gas hydrates in the world can be either of Coal-Derived or oil-Derived origin, but dominated by oil-Derived origin. A small amount of Coal-Derived gas was also found in the Qilian Mountain in China and the Vancouver Island in Canada. The Coal-Derived gas has relatively heavy δ13C1 ≥ −45‰ and δ13C2 > −28‰, while the oil-Derived gas has δ13C1 from −53‰ – −35‰ and δ13C2
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genetic types and origins of natural Gases from eastern fukang sub depression of the junggar basin nw china implication for low mature Coal Derived Gases
Natural Gas Geoscience, 2017Co-Authors: Deyu Gong, Yi Wang, Miao Yuan, Julei Mi, Shan Lu, Lili ZhaoAbstract:Abstract Although the Fukang Sub-depression is the largest hydrocarbon generation depression in the Junggar Basin and promises favorable potential for oil and gas exploration, only several small–medium oil/gas accumulations have been discovered so far. After analyzing the molecular and stable carbon isotopic compositions of natural Gases and its associated low molecular weight hydrocarbons (LMWHs) from eastern Fukang Sub-depression, their genetic types and origins are discussed in this study. Natural Gases are wet Gases with an average dryness coefficient of 0.84. Stable carbon isotopes of methane and ethane are well correlated with the thermal evolution trend of Coal-Derived Gases. The C 5–7 LMWHs are enriched in methyl cyclohexane but they lack n -alkanes, indicating a predominance of higher plant input. Gases have maturities ranging 0.76%–0.93% R o and are well consistent with their low n -heptane (H) and iso -heptane (I) contents. The geochemical characteristics of natural Gases from eastern Fukang Sub-depression are quite similar with those from the Turpan–Hami Basin. Their Gases are considered to be low-mature Gases Derived from the Lower–Middle Jurassic Coal measures. In contrast, they show remarkable differences with those from the Wucaiwan gas field; they are considered to have high-mature Gases Derived from the Carboniferous Coal measures.
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stable hydrogen and carbon isotopic ratios of Coal Derived Gases from the turpan hami basin nw china
International Journal of Coal Geology, 2015Co-Authors: Yunyan Ni, Deyu Gong, Dijia Zhang, Fengrong Liao, Fei Yu, Jingzhi Yu, Jianping Chen, Changyi Zhao, Jian HuAbstract:Abstract Natural Gases from the Qiudong and Hongtai gas fields in the Taibei sag in the Turpan-Hami Basin of China were analyzed for stable hydrogen and carbon isotopic characteristics, to investigate the origin of the gas and the gas-source correlation. Natural Gases from the two gas fields are dominated by alkane Gases with methane content varying from 81.61% to 92.57%. Dryness ranges from 0.76 to 0.93, indicating an abundance of wet gas. The carbon and hydrogen isotopic compositions of the methane vary from − 39.8‰ to − 42.6‰ and from − 263‰ to − 279‰ in the Qiudong gas field, respectively, and from − 37.7‰ to − 39.0‰ and from − 250‰ to − 257‰ in the Hongtai gas field, respectively. All Gases have a characteristic carbon and hydrogen isotopic distribution pattern among the C1–C5 alkanes, in which δ13CCH4
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stable carbon isotopes of Coal Derived Gases sourced from the mesozoic Coal measures in china
Organic Geochemistry, 2014Co-Authors: Deyu Gong, Yunyan Ni, Shipeng Huang, Wei WuAbstract:Coal-Derived, large scale gas fields Derived from the Mesozoic Coal measures in China are mainly distributed in the Middle–Lower Jurassic Coal measures in the Tarim, Junggar and Turpan-Hami basins in northwest China, and the Upper Triassic Xujiahe Formation Coal measure in Sichuan Basin, central China. In 2011, the annual production was 21.6 × 109 m3 and the proved geological reserves were 2485 × 109 m3, accounting for 21% and 30% of the total in China, respectively. Based on analyses of gas composition and stable carbon isotopes ratios of 203 samples and stable carbon isotopes of 102 CO2 samples, the following conclusions were made. (a) Based on diagnostic plots using the stable carbon isotopic and molecular composition of gas samples, alkane gas from the Mesozoic Coal measures in China is shown to be Coal-Derived. (b) According to the δ13C2 vs. C2H6 plot of a great number of oil-Derived and Coal-Derived Gases in China, it is concluded that Gases with δ13C2 > −28.5‰ are Coal-Derived and those with δ13C2 < −28.5‰ are oil-Derived in most cases. (c) Among the natural Gases from the Mesozoic Coal measures in China, primary Coal-Derived Gases with normal carbon isotopic distribution pattern among the C1–C4 alkanes (i.e. δ13C1 < δ13C2 < δ13C3 < δ13C4) are dominant. (d) Carbon isotopic pattern reversal mainly results from the mixing of Coal-Derived Gases having different maturities but the same source and secondly from microbial oxidation of propane (e.g. Mu 3 and Mu 4 wells in the Gumudi gas field, Junggar Basin). (e) CO2 in the Coal-Derived Gases from the Mesozoic Coal measures in China has both biogenic and abiogenic origins. The biogenic origin is dominant and the abiogenic CO2 is mainly found in the Kuqa Depression in the Tarim Basin and western Sichuan Basin. (f) Isotopic differences between heavy hydrocarbon Gases and methane become less with increasing maturity.
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stable hydrogen and carbon isotopic ratios of Coal Derived and oil Derived Gases a case study in the tarim basin nw china
International Journal of Coal Geology, 2013Co-Authors: Yunyan Ni, Wei Wu, Dijia Zhang, Fengrong Liao, Shuichang Zhang, Jin Su, Deyu GongAbstract:Abstract Natural Gases from the Kuqa depression, Lunnan and Tazhong low uplifts in the Tarim basin of China were analyzed for stable hydrogen and carbon isotopic characteristics, to compare the isotopic differences, particularly of hydrogen, between Coal-Derived and oil-Derived Gases. Gases from the Kuqa depression are Coal-Derived and sourced from Middle–Lower Jurassic Coal measures, possibly with a minor contribution from Triassic lacustrine mudstones. Gases from the Lunnan and Tazhong low uplifts are thought to be sourced from Cambrian–Lower Ordovician marine sapropelic organic matter. Natural Gases from the Lunnan low uplift and Ordovician strata in the Tazhong low uplift are oil-cracked, and Gases from the Carboniferous and Silurian strata in the Tazhong low uplift are oil-associated. Most Gases have expected hydrogen isotopic distributions among C 1 –C 3 alkanes, i.e., δ 2 H CH4 2 H C2H6 2 H C3H8 . However, nearly all samples that show carbon isotopic reversal between C 1 and C 2 alkanes (δ 13 C CH4 > δ 13 C C2H6 ) in the Lunnan low uplift also have corresponding hydrogen isotopic reversal (δ 2 H CH4 > δ 2 H C2H6 ) between these alkanes. In the Tazhong low uplift, except for the Silurian Gases, nearly all the Carboniferous and Ordovician Gases have regular carbon isotopic distribution pattern among C 1 –C 2 alkanes (δ 13 C CH4 13 C C2H6 ) but with hydrogen isotopic reversal between C 1 and C 2 alkanes (δ 2 H CH4 > δ 2 H C2H6 ). This probably indicates that except the influences of mixing with Gases at different maturity, hydrogen isotopes of natural Gases are also sensitive to other processes such as hydrogen exchange between water and organic matter during thermal maturation. No analytical differences in δ 2 H CH4 have been found between Coal-Derived Gases sourced from continental humic organic matter in the Kuqa depression and the oil-Derived Gases sourced from the Carboniferous and Silurian marine sapropelic organic matter in the Tazhong low uplift. All Coal-Derived Gases in the Kuqa depression have δ 2 H CH4 values less than − 150‰, while the oil-cracked Gases in the Lunnan low uplift and the Ordovician oil-cracked Gases in the Tazhong low uplift have slightly greater δ 2 H CH4 values (>− 150‰). However, the Silurian and Carboniferous oil-associated Gases in the Tazhong low uplift also have quite low δ 2 H CH4 values (around − 160‰). The clearly different hydrogen isotopic values of Gases from different strata in the Tazhong low uplift and the close hydrogen isotopic values between Gases from the Kuqa depression and Silurian and Carboniferous strata in the Tazhong low uplift, all imply that hydrogen isotopes of alkane Gases are influenced by factors more than thermal maturity and depositional environments. Great care needs to be paid when using the hydrogen isotopes for gas genetic study, and a combination with local geological settings and other geochemical features is suggested. This is because hydrogen isotopes of alkane Gases in one basin may be not applicable in the other basins.
Wei Wu - One of the best experts on this subject based on the ideXlab platform.
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stable carbon isotopes of Coal Derived Gases sourced from the mesozoic Coal measures in china
Organic Geochemistry, 2014Co-Authors: Deyu Gong, Yunyan Ni, Shipeng Huang, Wei WuAbstract:Coal-Derived, large scale gas fields Derived from the Mesozoic Coal measures in China are mainly distributed in the Middle–Lower Jurassic Coal measures in the Tarim, Junggar and Turpan-Hami basins in northwest China, and the Upper Triassic Xujiahe Formation Coal measure in Sichuan Basin, central China. In 2011, the annual production was 21.6 × 109 m3 and the proved geological reserves were 2485 × 109 m3, accounting for 21% and 30% of the total in China, respectively. Based on analyses of gas composition and stable carbon isotopes ratios of 203 samples and stable carbon isotopes of 102 CO2 samples, the following conclusions were made. (a) Based on diagnostic plots using the stable carbon isotopic and molecular composition of gas samples, alkane gas from the Mesozoic Coal measures in China is shown to be Coal-Derived. (b) According to the δ13C2 vs. C2H6 plot of a great number of oil-Derived and Coal-Derived Gases in China, it is concluded that Gases with δ13C2 > −28.5‰ are Coal-Derived and those with δ13C2 < −28.5‰ are oil-Derived in most cases. (c) Among the natural Gases from the Mesozoic Coal measures in China, primary Coal-Derived Gases with normal carbon isotopic distribution pattern among the C1–C4 alkanes (i.e. δ13C1 < δ13C2 < δ13C3 < δ13C4) are dominant. (d) Carbon isotopic pattern reversal mainly results from the mixing of Coal-Derived Gases having different maturities but the same source and secondly from microbial oxidation of propane (e.g. Mu 3 and Mu 4 wells in the Gumudi gas field, Junggar Basin). (e) CO2 in the Coal-Derived Gases from the Mesozoic Coal measures in China has both biogenic and abiogenic origins. The biogenic origin is dominant and the abiogenic CO2 is mainly found in the Kuqa Depression in the Tarim Basin and western Sichuan Basin. (f) Isotopic differences between heavy hydrocarbon Gases and methane become less with increasing maturity.
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stable hydrogen and carbon isotopic ratios of Coal Derived and oil Derived Gases a case study in the tarim basin nw china
International Journal of Coal Geology, 2013Co-Authors: Yunyan Ni, Wei Wu, Dijia Zhang, Fengrong Liao, Shuichang Zhang, Jin Su, Deyu GongAbstract:Abstract Natural Gases from the Kuqa depression, Lunnan and Tazhong low uplifts in the Tarim basin of China were analyzed for stable hydrogen and carbon isotopic characteristics, to compare the isotopic differences, particularly of hydrogen, between Coal-Derived and oil-Derived Gases. Gases from the Kuqa depression are Coal-Derived and sourced from Middle–Lower Jurassic Coal measures, possibly with a minor contribution from Triassic lacustrine mudstones. Gases from the Lunnan and Tazhong low uplifts are thought to be sourced from Cambrian–Lower Ordovician marine sapropelic organic matter. Natural Gases from the Lunnan low uplift and Ordovician strata in the Tazhong low uplift are oil-cracked, and Gases from the Carboniferous and Silurian strata in the Tazhong low uplift are oil-associated. Most Gases have expected hydrogen isotopic distributions among C 1 –C 3 alkanes, i.e., δ 2 H CH4 2 H C2H6 2 H C3H8 . However, nearly all samples that show carbon isotopic reversal between C 1 and C 2 alkanes (δ 13 C CH4 > δ 13 C C2H6 ) in the Lunnan low uplift also have corresponding hydrogen isotopic reversal (δ 2 H CH4 > δ 2 H C2H6 ) between these alkanes. In the Tazhong low uplift, except for the Silurian Gases, nearly all the Carboniferous and Ordovician Gases have regular carbon isotopic distribution pattern among C 1 –C 2 alkanes (δ 13 C CH4 13 C C2H6 ) but with hydrogen isotopic reversal between C 1 and C 2 alkanes (δ 2 H CH4 > δ 2 H C2H6 ). This probably indicates that except the influences of mixing with Gases at different maturity, hydrogen isotopes of natural Gases are also sensitive to other processes such as hydrogen exchange between water and organic matter during thermal maturation. No analytical differences in δ 2 H CH4 have been found between Coal-Derived Gases sourced from continental humic organic matter in the Kuqa depression and the oil-Derived Gases sourced from the Carboniferous and Silurian marine sapropelic organic matter in the Tazhong low uplift. All Coal-Derived Gases in the Kuqa depression have δ 2 H CH4 values less than − 150‰, while the oil-cracked Gases in the Lunnan low uplift and the Ordovician oil-cracked Gases in the Tazhong low uplift have slightly greater δ 2 H CH4 values (>− 150‰). However, the Silurian and Carboniferous oil-associated Gases in the Tazhong low uplift also have quite low δ 2 H CH4 values (around − 160‰). The clearly different hydrogen isotopic values of Gases from different strata in the Tazhong low uplift and the close hydrogen isotopic values between Gases from the Kuqa depression and Silurian and Carboniferous strata in the Tazhong low uplift, all imply that hydrogen isotopes of alkane Gases are influenced by factors more than thermal maturity and depositional environments. Great care needs to be paid when using the hydrogen isotopes for gas genetic study, and a combination with local geological settings and other geochemical features is suggested. This is because hydrogen isotopes of alkane Gases in one basin may be not applicable in the other basins.
Dijia Zhang - One of the best experts on this subject based on the ideXlab platform.
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stable hydrogen and carbon isotopic ratios of Coal Derived Gases from the turpan hami basin nw china
International Journal of Coal Geology, 2015Co-Authors: Yunyan Ni, Deyu Gong, Dijia Zhang, Fengrong Liao, Fei Yu, Jingzhi Yu, Jianping Chen, Changyi Zhao, Jian HuAbstract:Abstract Natural Gases from the Qiudong and Hongtai gas fields in the Taibei sag in the Turpan-Hami Basin of China were analyzed for stable hydrogen and carbon isotopic characteristics, to investigate the origin of the gas and the gas-source correlation. Natural Gases from the two gas fields are dominated by alkane Gases with methane content varying from 81.61% to 92.57%. Dryness ranges from 0.76 to 0.93, indicating an abundance of wet gas. The carbon and hydrogen isotopic compositions of the methane vary from − 39.8‰ to − 42.6‰ and from − 263‰ to − 279‰ in the Qiudong gas field, respectively, and from − 37.7‰ to − 39.0‰ and from − 250‰ to − 257‰ in the Hongtai gas field, respectively. All Gases have a characteristic carbon and hydrogen isotopic distribution pattern among the C1–C5 alkanes, in which δ13CCH4
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stable hydrogen and carbon isotopic ratios of Coal Derived and oil Derived Gases a case study in the tarim basin nw china
International Journal of Coal Geology, 2013Co-Authors: Yunyan Ni, Wei Wu, Dijia Zhang, Fengrong Liao, Shuichang Zhang, Jin Su, Deyu GongAbstract:Abstract Natural Gases from the Kuqa depression, Lunnan and Tazhong low uplifts in the Tarim basin of China were analyzed for stable hydrogen and carbon isotopic characteristics, to compare the isotopic differences, particularly of hydrogen, between Coal-Derived and oil-Derived Gases. Gases from the Kuqa depression are Coal-Derived and sourced from Middle–Lower Jurassic Coal measures, possibly with a minor contribution from Triassic lacustrine mudstones. Gases from the Lunnan and Tazhong low uplifts are thought to be sourced from Cambrian–Lower Ordovician marine sapropelic organic matter. Natural Gases from the Lunnan low uplift and Ordovician strata in the Tazhong low uplift are oil-cracked, and Gases from the Carboniferous and Silurian strata in the Tazhong low uplift are oil-associated. Most Gases have expected hydrogen isotopic distributions among C 1 –C 3 alkanes, i.e., δ 2 H CH4 2 H C2H6 2 H C3H8 . However, nearly all samples that show carbon isotopic reversal between C 1 and C 2 alkanes (δ 13 C CH4 > δ 13 C C2H6 ) in the Lunnan low uplift also have corresponding hydrogen isotopic reversal (δ 2 H CH4 > δ 2 H C2H6 ) between these alkanes. In the Tazhong low uplift, except for the Silurian Gases, nearly all the Carboniferous and Ordovician Gases have regular carbon isotopic distribution pattern among C 1 –C 2 alkanes (δ 13 C CH4 13 C C2H6 ) but with hydrogen isotopic reversal between C 1 and C 2 alkanes (δ 2 H CH4 > δ 2 H C2H6 ). This probably indicates that except the influences of mixing with Gases at different maturity, hydrogen isotopes of natural Gases are also sensitive to other processes such as hydrogen exchange between water and organic matter during thermal maturation. No analytical differences in δ 2 H CH4 have been found between Coal-Derived Gases sourced from continental humic organic matter in the Kuqa depression and the oil-Derived Gases sourced from the Carboniferous and Silurian marine sapropelic organic matter in the Tazhong low uplift. All Coal-Derived Gases in the Kuqa depression have δ 2 H CH4 values less than − 150‰, while the oil-cracked Gases in the Lunnan low uplift and the Ordovician oil-cracked Gases in the Tazhong low uplift have slightly greater δ 2 H CH4 values (>− 150‰). However, the Silurian and Carboniferous oil-associated Gases in the Tazhong low uplift also have quite low δ 2 H CH4 values (around − 160‰). The clearly different hydrogen isotopic values of Gases from different strata in the Tazhong low uplift and the close hydrogen isotopic values between Gases from the Kuqa depression and Silurian and Carboniferous strata in the Tazhong low uplift, all imply that hydrogen isotopes of alkane Gases are influenced by factors more than thermal maturity and depositional environments. Great care needs to be paid when using the hydrogen isotopes for gas genetic study, and a combination with local geological settings and other geochemical features is suggested. This is because hydrogen isotopes of alkane Gases in one basin may be not applicable in the other basins.
Fengrong Liao - One of the best experts on this subject based on the ideXlab platform.
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stable hydrogen and carbon isotopic ratios of Coal Derived Gases from the turpan hami basin nw china
International Journal of Coal Geology, 2015Co-Authors: Yunyan Ni, Deyu Gong, Dijia Zhang, Fengrong Liao, Fei Yu, Jingzhi Yu, Jianping Chen, Changyi Zhao, Jian HuAbstract:Abstract Natural Gases from the Qiudong and Hongtai gas fields in the Taibei sag in the Turpan-Hami Basin of China were analyzed for stable hydrogen and carbon isotopic characteristics, to investigate the origin of the gas and the gas-source correlation. Natural Gases from the two gas fields are dominated by alkane Gases with methane content varying from 81.61% to 92.57%. Dryness ranges from 0.76 to 0.93, indicating an abundance of wet gas. The carbon and hydrogen isotopic compositions of the methane vary from − 39.8‰ to − 42.6‰ and from − 263‰ to − 279‰ in the Qiudong gas field, respectively, and from − 37.7‰ to − 39.0‰ and from − 250‰ to − 257‰ in the Hongtai gas field, respectively. All Gases have a characteristic carbon and hydrogen isotopic distribution pattern among the C1–C5 alkanes, in which δ13CCH4
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stable hydrogen and carbon isotopic ratios of Coal Derived and oil Derived Gases a case study in the tarim basin nw china
International Journal of Coal Geology, 2013Co-Authors: Yunyan Ni, Wei Wu, Dijia Zhang, Fengrong Liao, Shuichang Zhang, Jin Su, Deyu GongAbstract:Abstract Natural Gases from the Kuqa depression, Lunnan and Tazhong low uplifts in the Tarim basin of China were analyzed for stable hydrogen and carbon isotopic characteristics, to compare the isotopic differences, particularly of hydrogen, between Coal-Derived and oil-Derived Gases. Gases from the Kuqa depression are Coal-Derived and sourced from Middle–Lower Jurassic Coal measures, possibly with a minor contribution from Triassic lacustrine mudstones. Gases from the Lunnan and Tazhong low uplifts are thought to be sourced from Cambrian–Lower Ordovician marine sapropelic organic matter. Natural Gases from the Lunnan low uplift and Ordovician strata in the Tazhong low uplift are oil-cracked, and Gases from the Carboniferous and Silurian strata in the Tazhong low uplift are oil-associated. Most Gases have expected hydrogen isotopic distributions among C 1 –C 3 alkanes, i.e., δ 2 H CH4 2 H C2H6 2 H C3H8 . However, nearly all samples that show carbon isotopic reversal between C 1 and C 2 alkanes (δ 13 C CH4 > δ 13 C C2H6 ) in the Lunnan low uplift also have corresponding hydrogen isotopic reversal (δ 2 H CH4 > δ 2 H C2H6 ) between these alkanes. In the Tazhong low uplift, except for the Silurian Gases, nearly all the Carboniferous and Ordovician Gases have regular carbon isotopic distribution pattern among C 1 –C 2 alkanes (δ 13 C CH4 13 C C2H6 ) but with hydrogen isotopic reversal between C 1 and C 2 alkanes (δ 2 H CH4 > δ 2 H C2H6 ). This probably indicates that except the influences of mixing with Gases at different maturity, hydrogen isotopes of natural Gases are also sensitive to other processes such as hydrogen exchange between water and organic matter during thermal maturation. No analytical differences in δ 2 H CH4 have been found between Coal-Derived Gases sourced from continental humic organic matter in the Kuqa depression and the oil-Derived Gases sourced from the Carboniferous and Silurian marine sapropelic organic matter in the Tazhong low uplift. All Coal-Derived Gases in the Kuqa depression have δ 2 H CH4 values less than − 150‰, while the oil-cracked Gases in the Lunnan low uplift and the Ordovician oil-cracked Gases in the Tazhong low uplift have slightly greater δ 2 H CH4 values (>− 150‰). However, the Silurian and Carboniferous oil-associated Gases in the Tazhong low uplift also have quite low δ 2 H CH4 values (around − 160‰). The clearly different hydrogen isotopic values of Gases from different strata in the Tazhong low uplift and the close hydrogen isotopic values between Gases from the Kuqa depression and Silurian and Carboniferous strata in the Tazhong low uplift, all imply that hydrogen isotopes of alkane Gases are influenced by factors more than thermal maturity and depositional environments. Great care needs to be paid when using the hydrogen isotopes for gas genetic study, and a combination with local geological settings and other geochemical features is suggested. This is because hydrogen isotopes of alkane Gases in one basin may be not applicable in the other basins.
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Discussion on the gas source of the Triassic Xujiahe Formation tight sandstone gas reservoirs in Yuanba and Tongnanba, Sichuan Basin: An answer to Yin Feng et al.
Petroleum Exploration and Development, 2013Co-Authors: Fengrong Liao, Yunyan NiAbstract:Abstract Gas-source correlation is generally focused on the genetic type of the main gas components, dominantly oil-associated gas or Coal-Derived gas. Gases from the Yuanba and Tongnanba gas reservoirs are dominated by methane with an average content of 95.36%. The average contents of ethane, propane, butane are 1.60%, 0.29% and 0.09%, respectively. In general, for the Yuanba and Tongnanba gas reservoirs, alkane gas has an average content of 97.34%, and CO 2 has an average content of 0.63%, which only accounts for 6.5‰ of the methane. According to the discrimination criteria that δ 13 C 2 value is greater than −28‰ for Coal-Derived gas and lower than −28.5‰ for the oil-associated gas, Yin et al. suggested that the Gases from the Yuanba gas reservoir be a mixture of Coal-Derived and oil-associated Gases, and the Gases from the Tongnanba gas reservoir be oil-associated gas. However, the discrimination criteria of δ 13 C 2 for Coal-Derived and oil-associated Gases are only valid when the alkane Gases have not undergone secondary alteration and have positive carbon isotopic series among C 1 –C 4 alkanes. Hence, it is concluded that Gases from the Yuanba and Tongnanba gas reservoirs are Coal-Derived Gases due to their high content and heavy carbon isotopic values of methane (−31.3‰), which is typical for high mature Coal-Derived Gases in the world. Though Yin et al. suggested that abiogenic CO 2 of these two reservoirs is originated from metamorphism or hydrolysis of deep carbonate rocks, we proposed that these CO 2 Gases are self-generated and self-accumulated under the corrosion of calcarenaceous sandstone of the Triassic Xujiahe Formation.