柴达木盆地北缘东段中下侏罗统孢粉相及生烃潜力

孢粉相是反映沉积物及其成岩作用环境的沉积有机质组合。为了评价柴达木盆地北缘东段中下侏罗统烃源岩生烃潜力，对中下侏罗统孢粉相进行了详细研究，基于有机质组份的鉴定和统计，将中下侏罗统划分为5个孢粉相带：第Ⅰ孢粉相带为煤质—具结构陆生质有机质组合，分布在小煤沟组；第Ⅱ孢粉相带为无定型有机质组合，分布在大煤沟组1段；第Ⅲ孢粉相带为煤质—草质有机质组合，分布在大煤沟组2～4段。第Ⅳ孢粉相带为无定型—草质有机质组合，分布在大煤沟组5段；第Ⅴ孢粉相带为无定型—半无定型—结构水生质有机质组合，分布在大煤沟组第7段。大煤沟组第1段、第7段烃源岩孢粉相带有机质类型最好，是最有利的生油气层段，其次是大煤沟组第5段，其它层段生烃潜力差。

Palynofacies and Oil Potential of Lower-Middle Jurassic in the East Part of Northern Qaidam Basin

Palynofacies is a particular sedimentary organic matter, which can reflect sedimentation and lithogenesis environment. In order to evaluate petroleum generating potential of source rock, the palynofacies of lower-middle Jurassic in the east part of northern Qaidam basin have been researched in detail, Based on the identification and statistics of the organic matter, the lower-middle Jurassic may be divided into five palynofacies zones. The first zone distributes in the Xiaomeigou formation, which belongs to assemblage of fusinite and structural terrestrial organic matter. The second zone distributes in the first member of Dameigou formation, which belongs to assemblage of amorphous organic matter. The third zone distributes in the second to fourth members of the Dameigou formation, which belongs to assemblage of fusinite and grass organic matter. The fourth zone distributes in the fifth member of the Dameigou formation, which belongs to assemblage of grass and amorphous organic matter. The fifth zone distrib- utes in the seventh member of the Dameigou formation, which belongs to assemblage of amorphism, semi-amorphism and structural aquatic organic matter. According to the palynofacies analysis, the oil generating potential of these strata has been evaluated. It is indicated that the first and the seventh members of Dameigou formation are the best of oil-generating beds, and the fifth member of Dameigou formation is secondly. The other members is worse.