摘要
鲁卜哈利盆地B区块油气勘探获得天然气和凝析油。A2井奥陶系凝析油以小于nC17的正构烷烃为主,凝析油全油碳稳定同位素值为-26.55‰^-27.70‰。凝析油具有饱和烃含量高、不含沥青质、呈现饱和烃>芳烃>非烃的特征。庚烷值和异庚烷值分别为22%和2.38。凝析油生物标志化合物含量低,萜烷系列以藿烷为主,三环萜烷以C23三环萜烷为主,C24四环萜烷含量低,甾烷组成上具有C29≈C27>C28的分布特征,重排甾烷含量高。凝析油生物标志化合物特征与来源于志留系热页岩的古生界原油相似。生物标志化合物和金刚烷成熟度表明原油为成熟—高成熟的范畴。B区块不同层位的天然气均为湿气,天然气为有机成因油型气,天然气的成熟度为0.75%~1.35%。由于B区块凝析油、天然气成熟度相当,认为原油裂解气不是该区天然气的唯一成因。凝析油和天然气主要直接来源于志留系热页岩的热降解。
Natural gas and small amount of condensates were obtained in Rub A1 Khali Basin. The Ordoviclan condensates from well A2, with carbon isotopic value from -26.55‰ to -27. 70‰, was dominated by the alkanes with carbon numbers smaller than 17. The condensates has high saturated fraction with no asphaltene. The content order of group composition is as follows： saturated fraction 〉 aromatic fraction〉 non-hydrocarbon fraction. The heptane and isoheptane values of the condensates are 22% and 2.38, respectively. The biomarker contents of the condensate are low,with hopane dominating in the terpanes and C23 tricyclic terpane dominating in tricyclic terpane,and low content of C24 tetracylic terpane. The condensates have high content of diasterane,with regular sterane distribution being C29≈C27 〉C28. The biomarker distribution of the Ordovician condensates is similar to that of the Paleozoic oils sourced from Silurian hot shale. The maturity parameters of biomarker and diamondoids suggest the condensates to be mature to high mature. All the natural gases from different time in Block B are wet gas of organic origin. The maturity of these gases ranges from 0.75% to 1.35%. Due to the similar maturity between the condensate and natural gas,it is suggested that the oil-cracking may not be the only gas origin. Condensates and natural gas may be mainly sourced from the thermal cracking of Silurian hot shale.
出处
《天然气地球科学》
EI
CAS
CSCD
北大核心
2014年第6期889-897,共9页
Natural Gas Geoscience
基金
国家科技重大专项'中东中亚富油气区大型项目勘探开发关键技术'(编号:2011ZX05031)资助
关键词
凝析油
天然气
地球化学
沙特B区块
古生界
鲁卜哈利盆地
Condensates
Natural gas
Geochemistry
Block B in Saudi Arabia
Paleozoic
Rub A1 Khali Basin
