N2 ORIGIN ANALYZE IN NATURAL GAS OF Y BASIN IN THE NORTH OF NANHAI, CHINA  

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  • China Offshore Oil Nan-hai West Corporation, Zhanjiang, 524057

Online published: 2000-06-20

Abstract

There contains non-hydrocarbon CO2 and N2 universally in natural gas of Y basin and the N2 content appear negative-correlate with overall of inorganic CO2 and positive-correlate with hydrocarbon gas which mainly is CH4. According to N2 content .natural gas can be divided into three typesjow N2 content(N2<10%) .middle N2 content(N2 = 10%-15%),high N2 content(N2>15%). According to its geology and geochemistry behaviors and characteristics of companion rare gas isotope the origin of N2 can be comprehensively discriminated and determined to three original types:atmospheric origin,shell origin and combination of shell origin of hydrocarbon and non-hydrocarbon. The distribution traits largely possess parti-tioned-area and partitioned-block on plate and concentrated in shallow layer or overshallow of 400-1600m on cross section. The co-existed grouping relation of N2,CO2 and hydrocarbon gas usually include natural gas of high-content N2association with low-content CO2 hydrocarbon gas of hydrocarbon origin and hydrocarbon gas of mainly high-content CH4,and N2nuaural gas of hydrocarbon and non-hydrocarbon combination origin coexisting with high-content CO2 of non-hydrocarbon and partly hydrocarbon gas which mainly is CH4. Obviously this co-existed grouping relation determine the traits of origin and composition of N2. So based on the origin type of N2 and co-existed grouping relation and distribution characteristics of N2, CO2 and hydrocarbon gas, associated with integrated analyzing and researching of geology and geochemistry, the source of N2 can be comprehensive discriminated and determined.

Cite this article

HE Jiaxiong, LI Mingxing . N2 ORIGIN ANALYZE IN NATURAL GAS OF Y BASIN IN THE NORTH OF NANHAI, CHINA  [J]. Natural Gas Geoscience, 2000 , 11(3) : 25 -34 . DOI: 10.11764/j.issn.1672-1926.2000.03.25

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