渤海湾盆地辽河坳陷兴隆台潜山变质岩地球化学特征

位于渤海湾盆地辽河坳陷西部凹陷中南部的兴隆台潜山内幕油藏是近年来国内潜山勘探的亮点,同时也给现有勘探方法带来了严峻挑战。在确定潜山变质岩岩相学特征的基础上开展地球化学研究,发现潜山变质岩主量元素富硅贫铁镁;微量元素P,Ti亏损,K,Pb富集;稀土元素总量高,轻稀土富集,曲线右倾,Eu异常不明显。这些特征说明兴隆台潜山变质岩原岩主要由同源大陆上地壳演化而来,油藏所在地区的断层切割地壳直达地幔的可能性较小。原岩恢复说明潜山中正副变质岩同时存在,变质岩具有呈层状展布的地质条件。这些认识对于兴隆台潜山内幕油藏勘探具有重要的理论指导意义。 

Geochemical characteristics of metamorphic rocks in Xinglongtai Buried Mountain, Liaohe Depression, Bohai Bay Basin

Interior reservoirs in the Xinglongtai Buried Mountain which locates at the central south of the Western Sag, the Liaohe Depression, the Bohai Bay Basin are highlights in recent domestic researches on buried mountain reservoirs. Meanwhile, they are also big challenges to current exploration methods and technologies. Geochemical studies on metamorphic rocks in buried mountain have been conducted based on their petrographic characteristics. It has been found out that major elements are rich in Si and poor in Fe and Mg. As to trace elements, P and Ti are poor and K and Pb are rich. ∑REE is high with LREE enrichment, right-inclining normalized REE pattern and inconspicuous Eu anomaly. All these characteristics have indicated that original rocks of metamorphic rocks come from cognate upper crust and there is little possibility for transcrustal deep faults development. Protolith restoration shows that both ortho-and para-rocks exist in the buried mountain at the same time occurring as stratiform body. All the above mentioned results have big theoretical significance for guiding reservoir explorations in the burial mountain.