论文部分内容阅读
对鄂尔多斯盆地南缘延长组长6—长9段烃源岩、油砂岩心样品进行了系统的采集,利用热解分析、TOC含量测定、有机碳同位素分析、GC/MS/MS测试等分析手段,对烃源岩生烃特征、沉积环境及油砂的油源特征进行了研究。结果表明:长6—长9段烃源岩均已达到成熟阶段,其中长7_3层为最好烃源岩层,其TOC含量平均为13.99%,干酪根类型主要为Ⅰ型;长6_2层次之,TOC含量平均为4.12%,干酪根类型主要为Ⅰ+Ⅱ_1型;长9段烃源岩TOC含量平均为2.85%,有机质类型主要为Ⅱ_1+Ⅱ_2型。长6—长9段烃源岩样品形成于典型的淡水湖泊环境,长8—长9段沉积时期Pr/Ph>1,沉积水体较浅,为亚氧化强氧化沉积环境,以陆源有机质输入为主;长6—长7段沉积时期Pr/Ph<1为还原环境,沉积水体较深,有机质来源为低等水生生物和陆源高等植物混源。研究区长6—长9段烃源岩生烃特征与其沉积环境息息相关,沉积环境还原性越强,陆源有机质输入越少,烃源岩生烃特征越好。聚类分析油源对比结果显示:研究区长7—长8段油砂样品的油源主要为长7_3层烃源岩。
The samples of source rocks and oil sand cores of 6-9 Chang9 Member of Yanchang Formation in the southern margin of Ordos Basin were systematically collected and analyzed by means of pyrolysis analysis, TOC determination, organic carbon isotope analysis and GC / MS / MS test , The hydrocarbon generation characteristics of source rocks, sedimentary environment and oil source characteristics of oil sands were studied. The results show that the source rocks of Chang 6 to Chang 9 have reached the maturity stage, of which the long 7-3 layer is the best source rock, with an average of 13.99% TOC and kerogen type I; The TOC content is 4.12% on average, and the kerogen type is mainly Ⅰ + Ⅱ 1 type. The TOC content of the source rocks in Chang 9 is 2.85% on average, and the organic matter type is mainly Ⅱ_1 + Ⅱ 2. The samples from source rocks of Chang 6 to Chang 9 are formed in a typical freshwater lake environment. Pr / Ph> 1 in the Chang 8 to Chang 9 depositional stages and shallow sedimentary water are the sub-oxidative strong oxidative sedimentary environments. The input of terrigenous organic matter is In the depositional period of Chang 6 to Chang 7, Pr / Ph <1 is the reducing environment, and the sedimentary water body is deeper. The source of organic matter is the mixed source of lower aquatic organisms and terrigenous higher plants. The hydrocarbon generation characteristics of the 6-9 Chang 9 Member source rocks are closely related to the sedimentary environment. The more reductive the depositional environment, the less input of terrigenous organic matter, the better the hydrocarbon generation characteristics of source rocks. The result of cluster analysis shows that the oil source of the 7th-8th oil sands in the study area mainly consists of long 7-3-layer source rocks.