塔里木盆地北部塔河油田原油分子地球化学特征及成因类型划分

Molecular Geochemistry and Classifications of Genetic Types of Petroleum from Tahe Oilfield of the Northern Tarim Basin

GC、GC—MS、GC-MS-MS分析表明，塔河1～7区块各油藏原油饱和烃、芳烃生物标志物组成和稳定碳同位素特征具有同源性，即塔河原油来自相同的烃源灶（或烃源层）。然而，对原油物性特征、成熟度特征、生物降解特征及原油馏分碳同位素组成等的深入研究发现，塔河原油属于早、晚两次充注成藏：早期充注为一般成熟型原油，相当于Ro值0．70％～0．80％成熟阶段的生排烃产物，遭受生物降解后具有重、稠油特征，主要分布在4、6、7区下奥陶统储层中；晚期成藏原油相当于Ro值0．80％～1．00％的高成熟阶段的生烃产物，表现为正常油、甚至轻质油或凝析油，在塔河油田广泛分布，并可以与早期充注油藏原油的生物降解残留成分进行充分混合，呈现复杂的地球化学特征。

The results of GC, GC-MS, and GC-MS-MS indicate that saturated hydrocarbon, arena biomarkers, and stable carbon isotope characteristics are of the same origin of oils from different zones in the Tahe Oilfield and oils were derived from the same source kitchen （ or oil source formation）. However, detail studies of oil physical properties, oil maturity, biodegradation, and stable carbon isotope of oil compositions revealed that the oil from the Tahe Oilfield has the early and later oil recharging periods. Earlier Oils with Ro values varying from 0.70% to 0.80% are now mainly distributed in zones 4, 6, and 7 of the Ordovician hydrocarbon pools from the Tahe Oilfield, and such oils have heavy or thick oil qualities due to the biodegradation. The subsequent oils with a high maturity of Ro values varying from 0. 80% to 1.00% widely distributed in the Tahe Oilfield, and they showed the physical properties of normal oil, clean oil, and condensate oil. Owing to the fully blending of the two recharging oils, the later one present a complex geochemistry.