One monoaromatic tricyclic diterpane and two aromatic tricyclic diterpanes were found in three low-maturity source rocks and five crude oils of the Tertiary Shahejie Formation in Shengli Oil Field. The compounds found...One monoaromatic tricyclic diterpane and two aromatic tricyclic diterpanes were found in three low-maturity source rocks and five crude oils of the Tertiary Shahejie Formation in Shengli Oil Field. The compounds found include C19H28 (m/z 145, M+ 256) ring-C monoaromatic tricyclic terpane, C17H20 (m/z 209, M+ 224) and C18H22 (m/z 223,M+ 238) rings-B,C diaromatic diterpanes. The results show that these compounds are biomarkers of immature organic matter with a stability sequence of C18H22 】 C17H20 】 C19H28. The cleavage of ring-D of pentacyclic triterpanoids, such as oleanene, hopene, fernene, ursene, in the early stage of diagenesis may be one of the origin pathways of rings-B, C diaromatic tricyclic diterpanes.展开更多
The characteristics of biomarker assemblage in the Early Tertiary immature source rocks from the third member (Es3) and the first member (Es1) of the Shahejie Formation, Eastern Depression, Liaohe Basin, China, are su...The characteristics of biomarker assemblage in the Early Tertiary immature source rocks from the third member (Es3) and the first member (Es1) of the Shahejie Formation, Eastern Depression, Liaohe Basin, China, are summarized. There is a strong odd-carbon number n-alkane predominance in the C23- C31 range with a maximum at nC27 or nC29. The occurrence of abundant resin-type biterpenoids and angiosperm-derived triterpenoids indicate the importance of higher plant input to sediments, while the presence of 4-methylsteranes in the Es1 and some Es3 samples reflect the significant contributions from aquatic organisms, i.e. dinoflagellates. In contrast, terrigenous higher plant is the major origin of organic matter in Ex3 source rocks, and in ES1 source rocks, the origin of organic matter is characterized by the mixture input of aquatic organisms and higher plants. In both typical terrestrial beds, relatively nigh concentration of dinosteranes, which may be derived from some specific freshwater dinoflagellates, were detected.展开更多
文摘One monoaromatic tricyclic diterpane and two aromatic tricyclic diterpanes were found in three low-maturity source rocks and five crude oils of the Tertiary Shahejie Formation in Shengli Oil Field. The compounds found include C19H28 (m/z 145, M+ 256) ring-C monoaromatic tricyclic terpane, C17H20 (m/z 209, M+ 224) and C18H22 (m/z 223,M+ 238) rings-B,C diaromatic diterpanes. The results show that these compounds are biomarkers of immature organic matter with a stability sequence of C18H22 】 C17H20 】 C19H28. The cleavage of ring-D of pentacyclic triterpanoids, such as oleanene, hopene, fernene, ursene, in the early stage of diagenesis may be one of the origin pathways of rings-B, C diaromatic tricyclic diterpanes.
文摘The characteristics of biomarker assemblage in the Early Tertiary immature source rocks from the third member (Es3) and the first member (Es1) of the Shahejie Formation, Eastern Depression, Liaohe Basin, China, are summarized. There is a strong odd-carbon number n-alkane predominance in the C23- C31 range with a maximum at nC27 or nC29. The occurrence of abundant resin-type biterpenoids and angiosperm-derived triterpenoids indicate the importance of higher plant input to sediments, while the presence of 4-methylsteranes in the Es1 and some Es3 samples reflect the significant contributions from aquatic organisms, i.e. dinoflagellates. In contrast, terrigenous higher plant is the major origin of organic matter in Ex3 source rocks, and in ES1 source rocks, the origin of organic matter is characterized by the mixture input of aquatic organisms and higher plants. In both typical terrestrial beds, relatively nigh concentration of dinosteranes, which may be derived from some specific freshwater dinoflagellates, were detected.
