塔河油田原油地球化学特征及新发现

Geochemical characteristics and new discoveries of crude oil in Tahe Oilfield

根据原油中生物标志化合物、原油物性、族组成等分析指标,对塔河油田原油地球化学特征进行详细分析。结果表明,塔河油田原油由下至上逐渐变轻;αααC_(29)S/(S+R)、αββC_(29)/(αα+ββ)、重排甾烷/规则甾烷等成熟度地化参数反映塔河油田原油均为成熟油;Pr/Ph、三环萜烷、C_(29)/C_(30)藿烷、C_(35)/C_(34)藿烷等参数反映其主要形成于海相还原环境,有机质来源于菌藻类;饱和烃色谱基线存在微弱“鼓包”、25-降藿烷的存在说明原油存在生物降解;三叠系原油中γ-羽扇烷的检出说明了三叠系原油存在陆相烃源岩的贡献。

Geochemical characteristics of crude oil in Tahe Oilfield were analyzed in details according to biomarkers,physical properties group composition and etc.The results show that the crude oil in Tahe Oilfield gradually becomes lighter from bottom to top;the maturity geochemical parameters ofαααC_(29)S/(S+R),αββC_(29)/(αα+ββ),rearranged steranes/regular steranes reflect that the crude oil in Tahe Oilfield is all mature.The parameters such as Pr/Ph,tricyclic terpenoids,C_(29)/C_(30)hopane,and C_(35)/C_(34)hopane indicate that they are mainly formed in a marine reducing environment,with organic matter derived from bacteria and algae.The presence of weak"bulges"in the baseline of saturated hydrocarbon chromatography and the presence of 25-norhopane indicate the biodegradation of crude oil.The detection ofγ-lupane in the Triassic oil indicates that the Triassic oil has a contribution of terrestrial source rock.