白音查干凹陷桑合地区油气来源

Oil-Source Correlation of Sanghe Region in Baiyinchagan Sag

白音查干凹陷桑合次洼发育都一段、腾格尔组、阿二段3套烃源岩,生烃时间长,成藏期次多,断层较为发育,具有形成混合原油的地质、地球化学条件。大量的原油生物标志物、碳同位素的数据分析表明,该地区原油可划分为原生低熟原油、原生成熟原油、混合原油3种类型。其中:原生低熟原油、原生成熟原油均来源于桑合次洼腾格尔下段—阿二段烃源岩,是该段烃源岩不同时期的生烃产物;混合原油来自前两类原油的混合作用,是典型的二元混合原油。

The Sanghe sub-sag in Baiyinchagan sag develops three sets of source rocks,i.e.the first Member of Duhongmu Formation,Tenggeer Formation and the second Member of Aershan Formation,with long hydrocarbon generation time,multiple-accumulation periods and well-developed faults.It is favorable for the formation of the commingle crude oil in the geological and geochemical conditions.The three sets of source rocks are the important oil sources in Sanghe region.The analytical data of biomarkers and carbon isotope from crude oil show that crude oil in the region can be divided into three types,primary low mature crude oil,primary mature crude oil,and blend crude oil.The first two types of which come from lower Member of Tenggeer Formation and the second Member of Aershan Formation,they are the hydrocarbon products in different periods of source rocks.The third type of crude oil,typical binary blend crude oil,comes from the mixing process of the first two types.