Origin and carbon isotope geochemistry characteristics of middle-shallow natural gas in the middle part of Western Sichuan Depression

  • GUO Ling ,
  • JIANG Zaixing ,
  • XU Jie
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  • 1. Geological Resources and Geological Engineering Postdoctoral Research Station, China University of Petroleum, Beijing 102249, China; 2. State Key Laboratory of Petroleum Resource and Prospecting, China University of Petroleum, Beijing 102249, China

Online published: 2011-12-20

Abstract

The middle part of Western Sichuan Depression is one of the major gas-producing areas in Sichuan Basin. However, there still exist some different opinions on the genesis and origin of middle-shallow natural gas in this area. In order to get a better understanding of the issues, the authors selected 56 gas samples and analyzed their carbon isotope compositions of C1 - C4, which were collected from producing wells in Xiaoquan-Xinchang-Hexingchang, Luodai-Xindu and Majing gas fields, and analyzed the origin of the middle-shallow natural gas combining with the natural gas composition and the source rock geochemistry characteristics. The population distribution of the methane carbon isotopes indicates a normal pattern of δ13C113C213C313C4. And the carbon isotopes showan obvious decrease vertically from the deeper Xu 4 member, Shaximiao, Suining and Penglaizhen formations until the shallower Lower Cretaceous gas reservoirs, reflecting the origin and migration characteristics of the natural gas. By means of calculating differences between δ13C2 and δ13C1, it could be concluded that the gas maturity increases from deep to shallow. In addition, the paper illustrated that the natural gas of Shaximiao, Suining and Penglaizhen formations in the study area behaves a type of pyrolysis gas and are mainly fromXu 5 and Xu 4 members, partly from Ziliujing Formation.

Cite this article

GUO Ling , JIANG Zaixing , XU Jie . Origin and carbon isotope geochemistry characteristics of middle-shallow natural gas in the middle part of Western Sichuan Depression[J]. Lithologic Reservoirs, 2011 , 23(6) : 18 -23 . DOI: 10.3969/j.issn.1673-8926.2011.06.004

References

[1] 郭兵,刘树根,刘顺,等.龙门山中段前山带构造特征及其形成演化[J].岩性油气藏,2008,20(4):59-64.
[2] 赵建成,刘树根,孙玮,等.龙门山与四川盆地结合部的油气保存条件分析[J].岩性油气藏,2011,23(1):79-85.
[3] 吴月先,钟水清,潘用平,等.四川盆地天然气“立体勘探”新进展[J].岩性油气藏,2009,21(1):128-132.
[4] 沈忠民,刘涛,吕正祥,等.川西坳陷侏罗系天然气气源对比研究[J].高校地质学报,2008,14(4):577-582.
[5] 郭吾正.四川盆地西部浅层致密砂岩天然气勘探模式[J].天然气工业,1997,17(3):5-13.
[6] 符晓,邓少云.川西新场气田中、浅层气藏特征及立体勘探开发的技术思路[J].天然气工业,1997,17(3):14-19.
[7] 蔡开平,廖仕孟.川西地区侏罗系气藏气源研究[J].天然气工业,2000,20(1):36-41.
[8] 朱光有,张水昌,梁英波,等.四川盆地天然气特征及气源[J].地学前缘,2006,13(2):234-248.
[9] 徐樟有,宋丽,吴欣松,等.川中地区上三叠统须家河组典型气藏解剖与天然气成藏主控因素分析[J].岩性油气藏,2009,21(2):7-11.
[10] 张富贵,刘家铎,孟万斌.川中地区须家河组储层成岩作用与孔隙演化研究[J].岩性油气藏,2010,22(1):30-36.
[11] James A T. Correlation of natural gas by wet of carbon isotopic distribution between hydrocarbon components[J]. AAPG Bulletin,1983, 67:117 6-119 1.
[12] Fuex A N. The use of stable carbon isotopes in hydrocarbon exploration[J]. Geochemistry Exploration,1997,7:155-188.
[13] 黄海平,许晓宏.天然气同位素特征及作用[J].石油与天然气地质,1997,18(3):136-139.
[14] 徐永昌.天然气成因理论及应用[M].北京:科学出版社,1994:359-361.
[15] 戴金星,倪云燕,邹才能,等.四川盆地须家河组煤系烷烃气碳同位素特征及气源对比意义[J].石油与天然气地质,2009,30(5):519-529.
[16] Rooney M A,Cloypool G E,Chung H M. Modeling thermogenic gas generation using carbon isotope ratios of natural gas hydrocarbons[J]. Chemical Geology,1995,126:219-232.
[17] 黄第藩,王兰生.川西北矿山梁地区沥青脉地球化学特征及其意义[J].石油学报,2008,29(1):23-28.
[18] Schoell M. Multiple origins of methane in the Earth[J]. ChemicalGeology,1988,71(1/3):1-10.
[19] 张义刚.天然气的生成聚集和保存[M].南京:河海大学出版社,1991:56.
[20] Prinzhofer A A, Huc A Y. Genetic and post-genetic molecular and isotopic fractionations in natural gases[J]. Chemical Geology,1995,126(3):281-290.
[21] Dow W G. Kerogen studies and geological interpretations[J]. Journal of Geochemical Exploration,1977,7:79-99.
[22] 戴金星,裴锡古,戚厚发.中国天然气地质学:卷一[M].北京:石油工业出版社,1992:144-145.
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