【作者】 杨春；

【导师】 戴金星；

【作者基本信息】 浙江大学 ， 地质学， 2009， 博士

【摘要】 松辽盆地深层存在油型气、煤成气、无机烷烃气以及无机二氧化碳气,是不同类型天然气研究的良好场所。在地质资料及大量地球化学数据分析的基础上,对松辽盆地深层天然气提出三种形成机理:（1）极低级浅变质岩具有一定生气潜力,在高演化阶段,单一热力作用可以引起重烃气碳同位素组成倒转;（2）建立放射成因氦同位素计算模型,肯定了CO₂/³He与CH₄/³He参数鉴别无机气存在的有效性,通过R/Ra与CO₂/³He和R/Ra与CH₄/³He关系模板,证明部分无机CH₄是CO₂通过F-T反应合成;（3）通过CO₂/³He与CO₂演化模式,芳深2井典型无机烷烃气藏可能存在大量CO₂丢失,并有部分CO₂通过F-T反应转化为CH₄。通过计算,松辽盆地深层徐家围子断陷无机CO₂和CH₄预测探明储量可达1663×10⁸m³和500×10⁸m³;徐家围子断陷基底深源有机气的生气强度只相当于主力烃源岩层的1/20,而主力烃源岩预计探明储量为7437×10⁸m³。本文通过对松辽盆地深层天然气成因类型厘定和数理模型计算,获得了不同成因类型天然气对深层气藏的贡献,不仅完善了天然气成因类型判识方法,丰富了天然气成藏模式,而且对松辽盆地深层天然气勘探也具有重要实践指导意义。更多还原

【Abstract】 There are different genetic types of natural gases in the deep strata of Songliao Basin, e.g.coal-derived gas, oil associated gas, oil cracking gas, abiogenic alkane gas and CO₂. Itprovides an excellent place for studies on mechanisms of genetic types. Three mechanismsare bringing forward in this paper. Firstly, at high thermal evolution stage, the very-low grademetamorphic can produce certain amount of gases, and the carbon isotopes of heavyhydrocarbons （C₁⁺） are reversed at single thermal agent. Secondly, by setting up theradiogenic helium calculation model, the validity of the parameters of CO₂/³He and CH₄/³Heare confirmed. According to the relationship of R/Ra and CO₂/³He, R/Ra and CH₄/³He, itverified that some the abiogenic methane are transformed from CO₂ by Fischer-Tropschsynthesis. Thirdly, through the evolutionary mode of CO₂/³He and CO₂, the typical abiogenicmethane from Fangshen 2 was resulted from dramatically lose of CO₂. The gas generationintensity of the basement is as 1/20 times as the main source rock is, and the most probableexplored reserves of abiogenic CO₂ and CH₄ can reach 1663×l0⁸m³ and 500×10⁸m³respectively. Consequently, the target for natural gas exploration in Xujiaweizi fualutdepression should be aimed at the thermalgenic methane beacuse the most probable exploredreserves of it are formed by the main source rocks in this area, which is 7437×10⁸m³. Theclarify of different genetic types of natural gases, their contributions for reserves and theirdistributions, all these results will be a important guiding for natural gas exploration in thedeep strata.更多还原