Abstract
The CO2 contents of natural gas from the eastern Sichuan Basin were mainly less than 2%, and they were generally large when the H2S contents were over 5%. The natural gas in the eastern Sichuan Basin showed high δ 13C1 values uncorrelated with H2S contents, and the oil-associated gas generally displayed carbon isotopic reversal between methane and ethane, whereas the coal-derived gas samples displayed positive series. The δ 13C values of CO2 in the natural gas could be divided into two types, one with low values (−24‰–−12‰) and the other with high values (−8‰–4‰). The natural gas had low R/Ra values and broad CO2/3He values distinct from the mantle-derived gas, and the CO2 was typical of crustal origin. Natural gas with high δ 13CCO2 values is distributed in the north region of the eastern Sichuan Basin, and CO2 in H2S-poor and H2S-free reservoirs was mainly derived from the thermal decomposition of carbonate rocks under Permian magmatism and high heat flow, whereas CO2 in the gas reservoirs with high TSR extent was derived mainly from the dedolomitization of carbonate reservoirs under acidic formation water, and the CO2 of TSR origin generally entered into the secondary calcite. The CO2 in natural gas in the south-central region of the eastern Sichuan Basin, which had been rarely affected by the Emeishan mantle plume, displayed low δ 13C values and was of organic origin. Though the natural gas in Wolonghe gas field had experienced TSR, the low reaction extent and weak acidity of formation water could hardly have resulted in the dedolomitization, and therefore CO2 in the natural gas was mainly of TSR origin with low δ 13C values.
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Cai C F, Worden R H, Bottrell S H, et al. Thermochemical sulphate reduction and the generation of hydrogen sulphide and thiols (mercaptans) in Triassic carbonate reservoirs from the Sichuan Basin, China. Chem Geol, 2003, 202: 39–57
Cai C F, Xie Z Y, Worden R H, et al. Methane-dominated thermochemical sulphate reduction in the Triassic Feixianguan Formation East Sichuan Basin, China: Towards prediction of fatal H2S concentrations. Mar Pet Geol, 2004, 21: 1265–1279
Xie Z Y, Tian S C, Li J, et al. Geochemical characteristics and origin of Feixianguan Formation oolitic shoal natural gases in northeastern Sichuan basin (in Chinese). Geochimica, 2004, 33: 567–573
Li J, Xie Z Y, Dai J X, et al. Geochemistry and origin of sour gas accumulations in the northeastern Sichuan Basin, SW China. Org Geochem, 2005, 36: 1703–1716
Zhu G Y, Zhang S C, Liang Y B, et al. Isotopic evidence of TSR origin for natural gas bearing high H2S contents within the Feixianguan Formation of the northeastern Sichuan Basin, southwestern China. Sci China Ser D-Earth Sci, 2005, 48: 1960–1971
Zhu G Y, Zhang S C, Liang Y B, et al. Dissolution and alteration of the deep carbonate reservoirs by TSR: An important type of deep-buried high-quality carbonate reservoirs in Sichuan basin (in Chinese). Acta Petrol Sin, 2006, 22: 2182–2194
Ma Y S, Cai X Y, Guo T L. The controlling factors of oil and gas charging and accumulation of Puguang gas field in the Sichuan Basin. Chin Sci Bull, 2007, 52 (Suppl I): 193–200
Ma Y S, Zhang S C, Guo T L, et al. Petroleum geology of the Puguang sour gas field in the Sichuan Basin, SW China. Mar Pet Geol, 2008, 25: 357–370
Ma Y S. Geochemical characteristics and origin of natural gases from Puguang gas field on eastern Sichuan Basin (in Chinese). Nat Gas Geosci, 2008, 19: 1–7
Zhu Y M, Wang J B, Hao F, et al. Geochemical characteristics and origin of natural gases from Xuanhan area, eastern Sichuan (in Chinese). Chin J Geol, 2008, 43: 518–532
Hao F, Guo T L, Zhu Y M, et al. Evidence for multiple stages of oil cracking and thermochemical sulfate reduction in the Puguang gas field, Sichuan Basin, China. AAPG Bull, 2008, 92: 611–637
Dai J X, Pei X G, Qi H F. Natural Gas Geology in China (Vol. 1) (in Chinese). Beijing: Petroleum Industry Press, 1992. 1–149
Dai J X, Song Y, Dai C S, et al. Geochemistry and accumulation of carbon dioxide gases in China. AAPG Bull, 1996, 80: 1615–1626
Wycherley H, Fleet A, Shaw H. Some observations on the origins of large volumes of carbon dioxide accumulations in sedimentary basins. Mar Pet Geol, 1999, 16: 489–494
Zhang T W, Zhang M J, Bai B J, et al. Origin and accumulation of carbon dioxide in the Huanghua depression, Bohai Bay Basin, China. AAPG Bull, 2008, 92: 341–358
Dai J X, Xia X Y, Wei Y Z, et al. Carbon isotope characteristics of natural gas in the Sichuan Basin, China (in Chinese). Pet Geol Exp, 2001, 23: 115–121
Hu A P, Chen H L, Yang S F, et al. Origin of natural gas and main controlling factors of reservoirs in Wolonghe gas field (in Chinese). Acta Pet Sin, 2008, 29: 643–649
Liu Q Y, Jin Z J, Gao B, et al. Origin of sour gas in the northeastern Sichuan Basin and fate action of Thermochemical Sulfate Reduction (TSR) to natural gas (in Chinese). Acta Geol Sin, 2009, 83: 1195–1202
Wang W C, Zhang X B, Luo H Y, et al. Carbon Isotopic characteristics of hydrocarbons and CO2 of H2S-rich natural gases and their origin in northeastern Sichuan Basin (in Chinese). Nat Gas Geosci, 2011, 22: 136–143
Huang S J, Huang K K, Tong H P, et al. Origin of CO2 in natural gas from the Triassic Feixianguan Formation of Northeast Sichuan Basin. Sci China Earth Sci, 2010, 53: 642–648
Liu D L, Song Y, Xue A M, et al. Integral Study of Tectonics and Natural Gas Accumulation in Sichuan Basin (in Chinese). Beijing: Petroleum Industry Press, 2000. 1–107
Wang Z C, Zhao W Z, Zhang L, et al. Structural Sequences and Natural Gas Exploration in Sichuan Basin (in Chinese). Beijing: Geological Publishing House, 2002. 1–287
Tong C G. Tectonic Evolution and Oil & Gas Accumulation of the Sichuan Basin (in Chinese). Beijing: Geological Publishing House, 1992, 1–128
Huang J Z, Chen S J, Song J R, et al. Hydrocarbon source systems and formation of gas fields in Sichuan Basin. Sci China Ser D-Earth Sci, 1997, 40: 32–42
Hu A P. Organic petrographic and organic geochemical studies of the sour gas accumulations in the Lower Triassic Feixianguan Formation, NE Sichuan Basin (in Chinese). Doctor Dissertation. Hangzhou: Zhejiang University, 2009. 81–133
Jiang X F, Xu R F, Huang J Z. Distribution characteristics of H2S in Feixianguan Formation gas pool, northeast Sichuan Basin (in Chinese). Nat Gas Ind, 2002, 22: 24–27
Huang S P, Liao F R, Wu X Q, et al. Distribution characteristics of hydrogen sulphide-bearing gas pools and the genesis of hydrogen sulphide in Sichuan Basin (in Chinese). Nat Gas Geosci, 2010, 21: 705–714
Bernard B B, Brooks J M, Sackett W M. Natural gas seepage in the Gulf of Mexico. Earth Planet Sci Lett, 1976, 31: 48–54
Dai J X, Dai C S, Song Y. Geochemical characters, carbon and helium isotopic compositions of natural gas from hot springs of some areas in China. Sci China Ser B, 1994, 37: 758–767
Mamyrin B A, Anufrier G S, Kamensky I L, et al. Determination of the isotopic composition of helium in the atmosphere. Geochem Int, 1970, 7: 498–505
Wang X B, Chen J F, Xu S, et al. Geochemical characteristics of gases from hot spring in seismic region. Sci China Ser B, 1994, 37: 242–249
Du J G, Cheng W Z, Zhang Y L, et al. Helium and carbon isotopic compositions of thermal springs in the earthquake zone of Sichuan, Southwestern China. J Asian Earth Sci, 2006, 26: 533–539
Ballentine C J, Schoell M, Coleman D, et al. Magmatic CO2 in natural gases in the Permian Basin, West Texas: Identifying the regional source and filling history. J Geochem Explor, 2000, 69-70: 59–63
Poreda R J, Jeffrey A W A, Kaplan I R, et al. Magmatic helium in subduction-zone natural gases. Chem Geol, 1988, 71: 199–210
Poreda R J, Craig H, Arnórsson S, et al. Helium isotopes in Icelandic geothermal systems: I. 3He, gas chemistry, and 13C relations. Geochim Cosmochim Acta, 1992, 56: 4221–4228
Xu Y C, Shen P, Tao M X, et al. Geochemistry on mantle-derived volatiles in natural gases from eastern China oil/gas provinces (I)—A novel helium resource-commercial accumulation of mantle-derived helium in the sedimentary crust. Sci China Ser D-Earth Sci, 1997, 40: 120–129
Xu Y G, Chung S L. The Emeishan large igneous province: evidence for mantle plume activity and melting conditions (in Chinese). Geochimica, 2001, 30: 1–9.
Zhang R X, Wang X Z, Lan D Q, et al. Reservoir evaluation of Emeishan basalt in southwest Sichuan (in Chinese). Nat Gas Explor Dev, 2006, 29: 17–20
Hou Z Q, Chen W, Lu J R. Eruption of the Continental Flood Basalts at −259 Ma in the Emeishan Large Igneous Province, SW China: Evidence from Laser Microprobe 40Ar/39Ar Dating. Acta Geol Sin, 2006, 80: 514–521
Zhu C Q, Ming X, Yuan Y S, et al. Palaeogeothermal response and record of the effusing of Emeishan basalts in Sichuan basin. Chin Sci Bull, 2010, 55: 949–956
Pan C C, Yu L P, Liu J Z, et al. Chemical and carbon isotopic fractionations of gaseous hydrocarbons during abiogenic oxidation. Earth Planet Sci Lett, 2006, 246: 70–89
Worden R H, Smalley P C. H2S-producing reactions in deep carbonate gas reservoirs: Khuff Formation, Abu Dhabi. Chem Geol, 1996, 133: 157–171
Ma Y S, Guo T L, Zhao X F, et al. The formation mechanism of high-quality dolomite reservoir in the deep of Puguang Gas Field. Sci China Ser D-Earth Sci, 2008, 51 (Suppl I): 53–64
Huang S J, Huang K K, Zhang X H, et al. Chemical Thermodynamics foundation of retrograde solubility for carbonate—Solution media related to CO2 (in Chinese). J Chengdu Univ Tech (Sci Tech ed), 2009, 36: 457–464
Yan Z W. Influences of SO4 2− on the solubility of calcite and dolomite (in Chinese). Carsol Sin, 2008, 27: 24–31
Chacko T, Cole D R, Horita J. Equilibrium oxygen, hydrogen and carbon isotope fractionation factors applicable to geologic systems. Rev Mineral Geochem, 2001, 43: 1–81
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Wu, X., Dai, J., Liao, F. et al. Origin and source of CO2 in natural gas from the eastern Sichuan Basin. Sci. China Earth Sci. 56, 1308–1317 (2013). https://doi.org/10.1007/s11430-013-4601-x
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DOI: https://doi.org/10.1007/s11430-013-4601-x