二连盆地下白垩统油气运移特征

应用二连盆地主要生油凹陷中泥、砂岩的分析化验等资料,系统分析了本区油气运移作用,总结了主力烃源层的油气运移特征。主要的认识为:1)本区下白垩统K₁ba和K₁bt¹2套成熟烃源岩排烃率可以达到32%~72%,是主力排烃层。进入生油高峰阶段的Ⅰ类生油凹陷有良好的生烃与排烃条件,具有形成工业价值油气藏的能力;2)根据泥岩压实曲线和粘土矿物变化等资料分析认为,快速压实阶段是排烃(油气初次运移)的最佳时期;3)从烃源岩生油期与排烃期的匹配关系分析,二连盆地只有Ⅰ类生油凹陷的成油带与泥岩快速压实阶段相吻合,构成油气生成与运移的良好匹配关系;4)油源断层和不整合面是油气二次运移的重要通道,特别是K₁bt¹/K₁ba不整合面具有良好的孔渗条件,其不整合面上、下的各种类型圈闭是油气勘探的主要目标;5)通过油气运移效应分析认为,乌里雅斯太凹陷原油运移效应最高,其次为阿南、赛汉塔拉、额仁淖尔凹陷,而巴音都兰和吉尔嘎郎图凹陷的原油未发生长距离运移。

MIGRATION CHARACTERISTICS OF OIL AND GAS OF THE LOWER CRETACEOUS,THE ERLIAN BASIN

Systemic research on oil and gas migration activities of main hydrocarbon generation sags in the Erlian basin is made based on experiment data from mud and sand. Migration characteristics of oil and gas is summarized as below: 1)Hydrocarbon discharge ratio of 2 sets of mature source rocks (K₁ba and K₁bt1) in the Lower Cretaceous is about 32%-72%, thus estimated as the main hydrocarbon discharge stratum. The type Ⅰ hydrocarbon generation sag which has entered the peak stage is favorable for hydrocarbon (generation and discharge. 2)Based on mudstone) compression curve and clay mineral change, the rapid compression stage is the most favorable era for hydrocarbon discharge(primary migration). 3)Hydrocarbon generation zone of only the type Ⅰ sag is matched with mud rapid compression stage, forming good relation between hydrocarbon generation and migration. 4)Source fault and unconformity surface are the main channels for secondary migration, especially the K₁bt1/K₁ba surface. 5)Hydrocarbon migration effect of the Wuliyasitai sag is the best, with that of the A'nan, Saihantala, Erennaoer sags worse. Crude oil in the Bayindulan and Jiergalangtu sags has not experienced long distance migration.