Petroleum Science >2012,??Issue 4:??455-462 DOI: https://doi.org/10.1007/s12182-012-0230-9
Application of butane geochemistry of naturalgas in hydrocarbon exploration Open?Access
文章信息
1 Institute of Mineral Resources, Chinese Academy of Geological Sciences, Beijing 100037, China 2 State Key Laboratory of Petroleum Resources and Prospecting, China University of Petroleum, Beijing 102249, China;2 State Key Laboratory of Petroleum Resources and Prospecting, China University of Petroleum, Beijing 102249, China;3 Luliang Oilfield Operation District, PetroChina Xinjiang Oilfield Company, Karamay, Xinjiang 834000, China;2 State Key Laboratory of Petroleum Resources and Prospecting, China University of Petroleum, Beijing 102249, China;4 Department of Natural Gas, PetroChina Tarim Oilfield Company, Korla, Xinjiang 841000, China;2 State Key Laboratory of Petroleum Resources and Prospecting, China University of Petroleum, Beijing 102249, China
文章摘要
characteristics of butane, the components and carbon isotopes of natural gas from major hydrocarbonbearing
basins in China were analyzed. The results showed that: (1) Oil-type gas has i-C4/n-C4<0.8,
δ13Cbutane <–28‰, δ13Ci-butane <–27‰, δ13Cn-butane<–28.5‰, whereas coal-type gas has i-C4/n-C4>0.8,
δ13Cbutane >–25.5‰, δ13Ci-butane>–24‰, δ13Cn-butane >–26‰. (2) When δ13Ci-butane–δ13Cn-butane is greater than 0,
the maturity of oil-type gas is generally more than 2.4% and that of coal-type gas is greater than 1.4%,
whereas when the difference is less than 0, the maturity of oil-type gas is generally less than 1.1% and
that of coal-type gas is less than 0.8%. (3) When natural gas migrates through dense cap rocks, the
value of i-C4/n-C4 increases, whereas when it migrates laterally along a reservoir, the value of i-C4/n-C4
decreases. (4) Sapropelic transition zone gas with composition and carbon isotopic signatures similar to
those of oil-type gas in the low thermal evolution stage is found to have a relatively high butane content.
(5) The values of i-C4/n-C4 andδ13Ci-butane–δ13Cn-butane of gas which has suffered biological degradation
are significantly higher than those obtained from thermogenic and bio-thermocatalytic transition zone
gas. Thus, natural gas of different genetic types can be recognized through component analysis and
carbon isotopic signatures of butane, the natural gas maturity can be estimated from the difference in
carbon isotopic content between isobutane and n-butane, and the migration direction of natural gas can
be determined from i-C4/n-C4 ratios and transport conditions, which can also be used to thermogenic and
bio-thermocatalytic transition zone gas.
关键词
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Natural gas, n-butane, isobutane, carbon isotope, genetic types of natural gas, migrationdirection