摘要
本文以拉布达林盆地下白垩统上库力组火山岩系中发育的一套优质烃源岩为研究对象,应用岩石热解、氯仿沥青抽提、镜质体反射率分析、饱和烃气相色谱分析和色谱-质谱分析以及全岩成分分析等多种方法和手段,探讨火山喷发活动对烃源岩中有机质成熟度、烃源岩生烃特征及优质烃源岩形成的影响。研究结果表明:烃源岩的有机质镜质体反射率(R_0)在0.56%～0.62%之间,最大热解温度(T_(max))在429～442℃之间,部分样品的氯仿沥青"A"转化率(A/TOC)和烃转化率(HC/TOC)分别>5%和>3%。上述各种参数均指示有机质成熟度处于低成熟阶段,说明火山喷发活动对烃源岩有机质成熟度影响不明显。在火山喷发活动和烃源岩相互作用过程中,火山岩中过渡金属元素发生迁移,致使烃源岩中过渡金属元素含量增加。由于过渡金属元素对烃源岩生烃有催化作用,因此,火山喷发活动可以促进烃源岩早生烃,有利于低熟油的形成。火山喷发活动带来的热液一方面给湖盆水体中的水生生物带来了大量的营养物质,促进水生生物繁殖,为优质烃源岩的形成奠定了丰富的物质基础;另一方面,火山热液使水体含盐度增加,形成还原环境,为有机质的保存和转化提供了有利条件。
This paper studies organic geochemistry of the source rocks related to volcanic rocks within the Shangkuli Formation of Labudalin basin by the analytic techniques of rock pyrolysis, chloroform bitumen extration, vitrinite reflectance analysis, gas chromatography (GC) and gas chromatography-mass spectrogram (GC-MS) analysis in order to constrain the relatioship between volcanism and source rocks. The results indicate that the vitrinite reflectances and peak temperature of pyrolysis (T(max)) of the source rocks range from 0.56% to 0.62% and from 429 to 442 degrees C, respectively, and that part of chloroform bieuminous 'A' conversion (A/TOC) and hydrocarbon conversion (HC/TOC) are more than 5% and more than 3%, respectively. The above mentioned characteristics suggest that the organic materials within the source rocks are similar to ones of low maturation stage, implying that the maturity of organic materials in the source rocks is not influenced by the volcanic activities. In addition, the transitive metal elements from the volcanic rocks are transferred to the source rocks during the interaction between the volcanism and the Source rocks. Based on the catalytic process of transitive metal elements during hydrocarbon generation, it is suggested that volcanic activities would cause the earlier hydrocarbon generation of source rocks and could favour the formation of low-mature oil. Taken together, it is proposed that the volcanism not only provides the materials for the formation of the excellent source rocks by the introduction of hydrothermal fluid resulting in the breeding of aquatic organisms, but also provides the favourable condition for the preservation and transformation of organic materials by the improvement of the salinity in sedimentary basin resulting in the formation of reductive environment.
出处
《岩石学报》
SCIE
EI
CAS
CSCD
北大核心
2009年第10期2671-2678,共8页
Acta Petrologica Sinica
基金
国家油气专项(XQ-2004-07 )资助成果.
