The trace elements in crude oils from Triassic Baikouquan formation, Permian and bitumens of Permian source rocks in Mahu sag in Junggar Basin have been analyzed. And on the basis of the contents and ratios of trace metals, like V, Cr, Ni and Mo, etc, the oils have been classified into three single-sourced oils (A1, A2 and B) and two groups of mixed oils (C1 and C2). Trace elements distribution of source rock bitumens were investigated, then the recognition chart of distinguishing mixed oils has been established. It is found that the transition metals like V, Cr, Cu, Mo are enriched in crude oils and the contents of rare earth elements (REE) are very low. The ratios of V/Ni, Co/Ni and Cr/Mo can be effective index for oil-source correlations. And A1 oils are mainly from P1 f carbonate source rocks, while A2 oils are from P1 f mudstones, and B oils are from P2 w mudstones. C1 are the mixtures of A1 and B, while C2 are the mixtures of A2 and B. This classification method has proven that the trace elements can be effective tools for high-maturity oil classification and oil-source correlations in complex geological conditions.%采用微量元素分析三叠系百口泉组和二叠系原油及烃源岩抽提物样品,利用V、Ni、Co、Mo等微量元素含量及其比值将准噶尔盆地玛湖凹陷原油划分为三类单源油(A1、A2、B)和两类混源油(C1、C2),分析烃源岩抽提物微量元素分布特征,建立混源油微量元素识别图版.结果表明:原油中普遍富集V、Cr、Ni、Cu、Mo等过渡金属元素,稀土元素(REE)含量则普遍较低;V/Ni、Co/Ni、Cr/Mo(元素含量比值)等可以作为油源对比的有效指标,A1类原油来源于风城组碳酸盐岩源岩,A2类来源于风城组泥岩类,B类则主要来源于乌尔禾组源岩,C1类为A1及B类混源,C2类为A2及B类混源;该划分方法进一步证明微量元素可以作为复杂高熟条件下原油类型划分及油源对比的有效工具.
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