论文部分内容阅读
通过分析川东北地区陆相储层天然气组分、碳同位素特征,并结合海相天然气数据进行天然气类型划分。对比海相和陆相天然气甲烷氢同位素组成δDCH4、稀有气体同位素40 Ar/36 Ar,分析陆相天然气的来源。不同区域陆相储层天然气的地球化学特征、成因类型及来源差别较大。通南巴地区的陆相储层天然气δ13C2值较低(<-29‰),δDCH4值分布范围较大(-186‰~-127‰)且跨越海、陆相分界线(-160‰),为海相来源油型气和陆相来源煤型气、油型气的不均匀混合,海相来源天然气贡献显著;元坝地区陆相储层天然气δ13C2值分布范围较大且跨越煤、油型气分界线(-29‰~-26‰),以煤型气为主,伴有少油型气,δDCH4值较低,为陆相地层自生自储型油型气;阆中地区陆相储层天然气δ13C2和δDCH4特征显示其为陆相来源的油型气。
By analyzing the natural gas composition and carbon isotope characteristics of terrestrial reservoirs in northeastern Sichuan, and combining with the natural gas data of the marine natural gas, the types of natural gas are classified. Comparing the isotopic composition δDCH4 of methane with that of marine natural gas and the Ar / 36 Ar isotope of rare gas, the source of terrestrial natural gas was analyzed. The geochemical characteristics, genetic types and origins of natural gas in terrestrial reservoirs in different regions are quite different. The δ13C2 value of terrestrial reservoirs in Tongnanba area is relatively low (<-29 ‰), and the distribution of δDCH4 is large (-186 ‰ ~ -127 ‰) and transgresses the demarcation line between sea and land (-160 ‰) The contribution of natural gas from marine sources is significant for the heterogeneous mixing of marine-derived oil-gas and continental-derived coal-gas and oil-gas, and δ13C2 distribution of terrestrial reservoirs in Yuanba is larger than that of coal and oil Gas boundary (-29 ‰ ~ -26 ‰), with coal-based gas, with less oil gas, δDCH4 value is low, for the continental strata self-storage reservoir type oil-gas; Langzhong terrestrial reservoir The δ13C2 and δDCH4 characteristics of natural gas show that they are oil-derived gases of continental origin.