摘要
未熟低熟油在南襄盆地泌阳凹陷广泛分布，并具有饱和烃含量较低、胶质和沥青质含量较高的特征。在分析泌阳凹陷未熟-低熟油地球化学特征的基础上，开展了精细油源对比，并研究了未熟-低熟油的形成条件。泌阳凹陷未熟一低熟油成熟度参数：C29ααα20S／（S十R）峰面积比值为0．10～0．33，C29ββ／（αα＋ββ）峰面积比值为0．11～0．28，Ys／（Ts＋Tm）峰面积比值均不大于0．34，具有未熟-低熟油成熟度低的特征。利用伽马蜡垸／C30藿烷峰面积比值和三环萜烷／（C29＋C30）藿垸峰面积比值两项指标将泌阳凹陷未熟一低熟油划分为A、B和C型。A型具有伽马蜡烷／C30藿烷峰面积比值和三环萜烷／（C29＋C30）藿烷峰面积比值都较低的“两低”特征，母源主要为核三段上部泥质烃源岩；B型具有伽马蜡垸／C30霍烷峰面积比值和三环萜烷／（C29＋C30）藿烷峰面积比值均较高的“两高”特征，与核三段下部泥质烃源岩具有很好的亲缘关系；C型具有伽马蜡垸／C30藿烷峰面积比值高，但三环萜烷/（C29＋C30）藿烷峰面积比值低的“一高一低”特征，源岩为核二段白云岩。研究表明泌阳凹陷核三段和核二段未熟一低熟烃源岩高可溶有机质含量和有利的生储组合关系是研究区未熟-低熟油形成的两个重要条件。
The immature to low-mature oils that are extensively distributed in the Biyang Depression of Nanxiang Basin are high in resin and asphaltene but low in the relative abundance of saturated hydrocarbon. Based on organic geochemical character analysis of the immature to low-mature oils, the origin and accumulation conditions of the immature to low-mature oils are studied. The value of C29ααα20S/（S＋R） of the immature to low-mature oils ranging from 0.10 to 0.33, the value of C29ββ/（αα＋ββ）, from 0. 11 to 0.28 and the value of Ts/（Ts ＋Tm） below 0. 34, indicate that the maturity of the immature to low-mature oils are very low. The immature to low-mature oils are divided into Type A, B and C by the parameters of Gammacerane/C30-hopane and tric-terpanes/（C29＋C30 ）- hopane. The immature to low-mature oils of Type A with the character of low values of Gammacerane/C30-hopane and tric-terpanes/（C29＋C30 ）-hopane is derived from the source rock of the top of the Eh3 formation. The crude oil of Type B with high values of Gammacerane/C30-hopane and tric-terpanes/（C29＋C30 ）-hopane values originates from the bottom of the Eh3 formation. Type C oils derived from the dolomite of the Eh2 formation are high in the value of Gammacerane/C30-hopane but low in tric-terpanes/（C29＋C30）-hopane. The studies indicate that the relatively high abundance of dissoluble organic matter in the source rock of the Eh2 and Eh3 formations and advantaged source-reservoir rock combinations are two accumulation conditions of the immature to low-mature oils in the Biyang Depression.
出处
《地质科技情报》
CAS
CSCD
北大核心
2008年第5期77-81,86,共6页
Geological Science and Technology Information
基金
中国石油集团公司项目“泌阳凹陷成烃成藏基础理论研究”
关键词
未熟-低熟油
油源对比
泌阳凹陷
immature and low-mature oil
oil-source correlation
Biyang Depression
