准噶尔盆地腹部地区原油金刚烷化合物特征及应用

Characteristics of diamondoids in crude oil and its application in hinterland of Junggar Basin

利用色谱/质谱/质谱方法分析了准噶尔盆地腹部地区原油中金刚烷化合物的含量,探讨了金刚烷参数指标在腹部地区原油类型划分和成熟度判识中的适用性。腹部地区原油中金刚烷类化合物含量较低,主要分布在(200~500)×10^-6。利用金刚烷类化合物浓度指标能够有效划分原油的类型,金刚烷异构化指标能够有效判识原油的成熟度。腹部地区原油主要分为两大类:Ⅰ类原油为早期相对低熟原油,金刚烷类化合物含量低,单金刚烷含量相对较高,浓度指标A/1-MA比值分布在0.50~0.71,成熟度指标MAI值较小,在0.41~0.50之间,主要分布在远离生烃凹陷区域;Ⅱ类原油为晚期相对高熟油,金刚烷类化合物含量较高,1-甲基单金刚烷含量较高,A/1-MA比值分布在0.30~0.37,MAI值在0.52~0.69之间,主要分布在生烃凹陷内,其分布格局与油气运移方向一致,即晚期充注的原油驱动早期充注的原油向远离生烃凹陷处运移,证实了腹部原油运移方向为盆1井西凹陷向北运移。

The content of diamondoids in crude oil from the hinterland of Junggar Basin was analyzed by GC,MS and GC-MS methods.The applicability of diamondoid indices to identify and evaluate oil maturity was discussed.The diamondoid content in crude oil is(200–500)×10^-6.The concentration index of diamondoids can classify oil types effectively,and the adamantane isomerization index can be used to evaluate oil maturity.The oil in the hinterland of Junggar Basin can be divided into two types.TypeⅠoils were generated early with relatively lower maturity and lower content of diamondoids.The content of adamantane is relatively higher.The concentration index A/1-MA ratio is distributed in the range of 0.50-0.71,and the maturity index MAI value is smaller,between 0.41 and 0.50,which is far away from the hydrocarbon source depression.TypeⅡoils were generated late with relatively higher maturity and higher content of diamondoids.The content of 1-methyladamantane is higher.The ratio of A/1-MA is in the range of 0.30-0.37,and the MAI value is between 0.52 and 0.69,which fall within the hydrocarbon source depression.The distribution pattern is consistent with the direction of oil migration.That is,the late filling oil displaced the early filling oil away from the hydrocarbon generation depression,which proves that the oil in the hinterland area migrated from the area of the well Pen 1 sag to the north.