| 摘要: |
| 通过天然气组分统计分析,结合区域构造演化、烃源岩成熟度历史、典型气藏解剖分析,确定考克潘索尔坳陷氮气的空间分布特征及其主控因素,包括有机质热演化程度、天然气运聚过程、基岩地层的高放射性等。研究表明:天然气组分中氮气含量在垂向上表现为下石炭统低、上泥盆统较高、二叠系最高的分布特点;泥盆系烃源岩大部分已经处于过成熟阶段,因此生成了富氮的天然气,在埋深较大的圈闭中,勘探的经济风险增加;二叠系气藏为典型的下生上储,靠断裂沟通下部烃源岩,天然气的高含氮也与高成熟天然气的垂向运聚密切相关,其总体勘探潜力不大。 |
| 关键词: 天然气组分 氮气成因 烃源岩成熟度 楚-萨雷苏盆地 |
| DOI：10.3969/j.issn.1673-5005.2015.04.005 |
| 分类号::TE.122.1 |
| 基金项目:国家“973”计划项目(2011CB2011) |
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| Distribution and origin of molecular nitrogen in natural gas of Kokpansor Depression, Chu-Sarysu Basin |
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WU Xinsong1,2, LI Na1, ZHOU Lianwu3, YU Da1, ZHA Yuming1
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(1.College of Geosciences in China University of Petroleum, Beijing 102249, China;2.The State Key Laboratory of Petroleum Resources and Prospecting, Beijing 102249, China;3.Dagang Oil Company, PetroChina, Tianjin 300280, China)
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| Abstract: |
| Based on the statistics of the natural gas composition,and by combining the areal structural evolution, the maturity of source rock and analysis of the key gas reservoir, this paper determined the distribution and the main controls of the molecular nitrogen in Kokpansor Depression, which include the maturity of source rock, the process of gas accumulation and the high radioactivity of the basement rock. The results show that the content of molecular nitrogen in natural gas is lower in the Lower Carboniferous, higher in the Upper Devonian and the highest in the Lower Permian. In Upper Devonian, most of the source rock was over-matured so that it generated the nitrogen-rich natural gas. The exploration risk in some deep buried traps maybe very high in such a case. On the other hand, gas pools in the Lower Permian belong to exogenetic accumulations and faults are the main channels of the gas input from the source rock. The higher nitrogen content in the Lower Permian is closely related to the long distance vertical migration of the over-matured natural gas. As a result,the exploration outlook of the Lower Permian is very limited. |
| Key words: Natural gas composition origin of the molecular nitrogen source rock maturity Chu-Sarysu Basin |
