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通过对惠民凹陷临南洼陷夏38井沙三段独立的辉绿岩侵入体以及阳信洼陷东部多层辉绿岩体周围烃源岩可溶有机质的地球化学分析,总结了侵入岩异常热作用对周围烃源岩生成油气地化特征的影响规律。受侵入岩影响形成的原油烃类组成特征及生物标志化合物特征均与正常成熟原油不同,且不同成熟度参数变化规律也存在较大差异。当岩浆侵入、烃源岩埋藏较深时,侵入体厚度较大的岩体能使正构烷烃组成中轻组分增加,主峰明显前移。当岩浆侵入、烃源岩埋藏较浅,且处于低成熟阶段时,侵入岩因影响程度不同,烃源岩中的正构烷烃组成会呈明显前峰型、双峰型或后峰型。岩浆侵入时的热作用主要是短时的高温作用。这一认识有助于确定侵入岩区油气受异常热影响程度,判断岩浆侵入时周围烃源岩的埋藏和演化情况。
Through the geochemical analysis of the dissolved organic matter in the source rocks of the third member of Shahejie Formation, Xia38 well in the Huimin Depression, and the multi-diabase bodies in the eastern part of the Yangxin Sag, the intrusive rocks Influence of anomalous thermal effects on the geochemical characteristics of hydrocarbon generation from surrounding source rocks. The characteristics of hydrocarbon composition and the characteristics of biomarker compounds formed by the intrusive rock are different from those of normal mature crude oil, and the variation of different maturity parameters are quite different. When the magma invaded and the source rock buried deeper, the intrusion body’s thick rock mass increased the light component of n-alkane composition and the main peak moved forward obviously. When the magma invades and the source rocks are shallow buried and in low maturity stage, the degree of influence of the intrusive rocks is different. The n-alkanes in the source rocks will show obvious pre-peak, bimodal or post-peak types. The thermal effect of magma intrusion is mainly the short-term high temperature effect. This understanding helps to determine the degree of anomalous heat affected by oil and gas in the intrusive rock and to determine the burial and evolution of the surrounding source rocks during magmatic intrusion.