二连盆地宝勒根陶海凹陷烃源岩生物标志化合物特征与油源对比

二连盆地宝勒根陶海凹陷虽然取得了很好的勘探成果，但油气成藏基础研究还非常薄弱。依据生物标志化合物特征对烃源岩进行分类，在此基础上开展油族划分和油源对比研究。地球化学特征表明，研究区有效烃源岩可划分为三类:第一类烃源岩为腾格尔组一段（K₁bt₁）中上部“高有机质丰度、低成熟度、高C₂₇甾烷相对含量、高伽马蜡烷含量、低Pr/Ph比值”烃源岩；第二类烃源岩为K₁bt₁下部“高有机质丰度、中等成熟度、中等C₂₇甾烷相对含量、中等伽马蜡烷含量”烃源岩；第三类烃源岩为阿尔善组（K₁ba）“较高有机质丰度、较高成熟度、低C₂₇甾烷相对含量、低伽马蜡烷含量、高Pr/Ph比值”烃源岩。依据生物标志化合物特征，油砂中的原油可划分成4个油族:油族1为K₁bt₁未熟油，原油来源于第一类烃源岩；油族2为K₁bt₁成熟油，原油来源于第二类烃源岩；油族3为K₁bt₁未熟油与K₁bt₁成熟油的混合油，原油来源于第一类烃源岩和第二类烃源岩；油族4为K₁bt₁成熟油与K₁ba成熟油的混合油，原油来源于第二类烃源岩和第三类烃源岩。从油气来源预测有利区，K₁bt₁烃源岩所指向的有利区的面积为26.85 km2，K₁ba烃源岩所指向的有利区面积为79.30 km2。

Biomarker Characteristics of Source Rocks and Oil Source Correlation in Baolegentaohai Sag,Erlian Basin

Although good exploration achievements have been made in Baolegentaohai Sag of Erlian Basin, the basic research on hydrocarbon accumulation is still very weak. In this study, source rocks are classified according to geochemical characteristics, and then oil group division and oil source correlation are carried out according to the characteristics of the biomarker compounds. The results show effective source rocks in the study area can be divided into three types: The first type, in the upper part of K₁bt₁, is characterized by high organic matter abundance, low maturity, high C₂₇-sterane relative content, high gammacerane content, and low Pr/Ph. The second type, in the lower part of K₁bt₁, is characterized by high organic matter abundance, medium maturity, and medium gammacerane and C₂₇-sterane relative content. The third type, in K₁ba, is characterized by relative high organic matter abundance, high maturity, low C₂₇-sterane content, low gammacerane content, and high Pr/Ph. Crude oil can be divided into four groups: Oil group 1 is K₁bt₁ immature oil, with hydrocarbons from the first type of source rock. Oil group 2 is K₁bt₁ mature oil, with hydrocarbons from the second type of source rock. Oil group 3 is a mixture of K₁bt₁ immature and K₁bt₁ mature oil, with hydrocarbons from the first and second types of source rocks. Oil group 4 is a mixture of K₁bt₁ mature and K₁ba mature oil, with hydrocarbons from the second and third types of source rocks. In terms of the favorable exploration area prediction by oil and gas sources, the favorable area predicted by K₁bt₁ source rock is 26.85 km2, and the favorable area predicted by K₁ba source rock is 79.30 km2.