Comparative analysis of characteristics and genesis of crude oils of the Zs block in the Tazhong area and the Ha 6 block in the Tabei area, Tarim basin

AbstractHa6 block is located in the north of the Tarim Basin. In this study, the characteristics of the Ordovician crude oil in the Ha6 block were analyzed by the gas chromatography-mass spectrometry (GC-MS) method on the basis of exploration and development data. The results show that C7 compounds are produced by type-I kerogen. According to the comparison, the medium-molecular-weight hydrocarbon fingerprint of the Cambrian crude oil in the Zs block is consistent with that of the Ordovician crude oil in the Ha6 block, which means that their sources are the same. In the two blocks, biological marker compounds of crude oil are also very similar: C27R, C28R, and C29R steranes are in a V-shaped pattern; the Ts/Tm ratio and the content of tricyclic terpanes are both high; and the presence of a large amount of aromatized isoprenoid indicates the crude oil was generated in a strong-reducing environment. In addition, the crude oil single molecule carbon isotope curve is similar with that of Wells Zs1 and Zs5. Th...