辽河坳陷冷东地区油气的聚集与混合

辽河坳陷冷东油田原油分析显示：富4-甲基甾烷、贫γ-蜡烷的原油（A类）主要分布于陈家洼陷内；贫4-甲基甾烷、富γ-蜡烷的原油（B类）主要分布于冷东断裂带中南部和雷家地区；具有中等含量4-甲基甾烷和γ-蜡烷的原油（C类）分布于冷东断裂带中北部。A类和B类原油分别源于本区沙三段和沙四段优质油源岩。C类原油的特征反映它是A、B两类原油的混合，它在储集层空间格局上的变化，显示原油成藏过程中后期原油（A类）灌注油藏的方向以及对早期原油（B类）的驱替与混合作用。

ACCUMULATION AND MIXING OF OIL AND GAS IN LENGDONG AREA, LIAOHE DEPRESSION

Geochemical analyses of the oils trapped in Lengdong area, Liaohe depression, revealed that: the oil (type A), which is richin 4-methylsterane and poor in gammacerane, mainly occurred in Chenjia sag; the oil (type B), which is poor in 4-methylsterane and rich in gammacerane , mainly occurred in the central south of the Lengdong structural zone and Leijia area ;the oil (type C) with middle abundance in 4-methylsterane and gammacerane occurred in the central north of the structuralzone. The former two kinds of oils (group A and B), are sourced from Es3 and Es4 formation respectively. The features ofgroup C oil show its results from the mixing of the group A and B oils, and its heterogeneities in spacial distribution indicatedthe filling direction of group A during its injection into reservoirs and the displacement and mixing with group B oil. A generaldiscussion about the contribution of group A oil and group B oil to the mixing of group C oil was made with the compositionalheterogeneitics.