石油与天然气地质 ›› 2010, Vol. 31 ›› Issue (6): 826-837.doi: 10.11743/ogg20100616

• 石油与天然气地质 • 上一篇    下一篇

中国南方海相优质烃源岩超显微有机岩石学与生排烃潜力

  

  • 出版日期:2010-12-28 发布日期:2011-02-09

Ultramicroscopic organic petrology and potential of hydrocarbon generation and expulsion of quality m arine source rocks in South China

  • Online:2010-12-28 Published:2011-02-09

PDF (PC)

626

被引次数

73

摘要：

通过选取中国南方不同层系优质烃源岩样品，综合运用全岩X-衍射、扫描电镜+能谱及生排烃模拟实验方法，对南方海相优质烃源岩矿物组成特征、有机质与矿物组成关系、有机质赋存形式、成烃生物及生排烃特征进行了研究。结果表明，海相优质烃源岩中石英、方解石、白云石等矿物主要是生物成因或与生物成因有关，烃源岩残余有机碳含量与石英含量具有正相关性，而与粘土矿物含量呈负相关。分析认为，南方海相优质烃源岩有机质主要有3种赋存状态:①有机质多与硅质相伴生，是南方海相优质烃源岩中最重要的赋存形式;②有机质与钙质相伴生，是部分二叠系优质钙质烃源岩的主要赋存形式;③有机质与粘土相伴生或被片状粘土颗粒包裹与硅质及钙质生屑一起共生，有机质赋存主要受沉积环境、沉积相控制。海相优质烃源岩成烃生物主要有藻类、底栖生物和菌类3种，同一烃源岩层位样品中往往含有“多重母质”分布。模拟实验表明，浮游藻类的生烃潜力与Ⅰ型干酪根生烃潜力相当，底栖藻类生烃潜力与Ⅱ型干酪根生烃潜力相当。富有机质硅质或钙质超微薄层容易使早期重质油排出，可以形成巨型重质油藏;而片状粘土之间包裹的有机质很难使早期生成的稠油排出，则形成轻质油气藏。

关键词: 赋存形式, 成烃生物, 生排烃, 有机岩石学, 海相烃源岩, 中国南方

Abstract:

Choosing samples of qualitymarine source rocks in various strata in South China，we make a study of mineral composition，correlation between organic matter and mineral composition，occurrences of organic matter，hydrocarbon-generating organism and features ofhydrocarbon generation and expulsion byways such aswhole rock X-ray diffraction，combined scanning electronmicroscope and energy spectrum，and simulated experimentof hydrocarbon generation and expulsion.The results show that minerals such as quartz，calcite and dolomite in these source rocks are mainly biogenetic or related to biogenetic origin.The total organic carbon content has a positive correlation with the quartz content but a negative correlation with clay minerals content.We believe that organic matter in these source rocks have threemain occurrences:1）organicmatter associated with siliceousmatter.It is the major occurrence in the qualitymarine source rocks in South China;2）organicmatter associated with calcareousmatter.It is the main occurrence in some quality calcareous source rocks in the Permian;3）organic matter associated with clay，or coated by flaky clay particles and associated with siliceous and calcareous bioclastics.In this case，the occurrence of organic matter is mainly controlled by depositional setting and sedimentary facies.There are mainly three kinds of hydrocarbonˉgenerating organisms:algae，benthos and fungus.Samples from the same layer of source rocks commonly contain multiple parentmaterials.According to the simulated experiments，the hydrocarbon-generating potential of floating algae is the same as TypeⅠkerogen，while that of benthos is the same as TypeⅡkerogen.Super thin siliceous or calcareous layers rich in organic matters are easy to expel early-generated heavy oil，and thus a giantheavy oil poolmay be formed.In contrast，organicmatter coated by flaky clay particles are hard to expel early-generated heavy oil，and thus a light oil poolmay be formed.

Key words: occurrence, hydrocarbon-generating organism, hydrocarbon generation and expulsion, organic petrolˉogy, marine source rock, South China