鄂尔多斯盆地子长油田杨家园则探区长6物源分析

Provenance analysis of the Sixth Member of the Yanchang Formation in the Yangjiayuanze oil prospect area, Zichang oilfield, Ordos basin

通过对鄂尔多斯盆地东北部子长油田杨家园则探区延长组长6砂岩的骨架矿物、重矿物、阴极发光、泥岩的稀土元素特征等的研究,并结合盆地东北缘典型露头剖面的古水流方向实测,分析了长6沉积期的古水流与主要物源方向,探讨了源区母岩性质。结果表明,研究区长6沉积期的古水流与主要物源方向来自北东方向。源区母岩以变质岩为主,其次少量火成岩。该研究结果对鄂尔多斯盆地东北部延长组砂体时空展布分析、有利油气聚集区带预测以及对研究区下一步的油气勘探部署都具有重要的理论意义和实际参考价值。

The authors analyzed the directions of paleocurrents and main sediment sources and features of parent rocks in the provenance during the deposition of the Sixth Member of the Yanchang Formation and studied the features of the parent rocks of the provenance based on the framework grains, heavy minerals, cathodoluminescence of framework grains and REE features of sandstone in the strata in the Yangjiayuanze oil prospect area, Zichang oilfield, northeastern Ordos basin, combined with measurements of the paleocurrent direction on typical outcrops located on the northeastern margin of the Ordos basin. The study shows that the paleocurrents and main sediment source were derived from the northeast during the deposition of the Sixth Member of the Yanchang Formation. The parent rocks of the provenance are mainly metamorphic rocks with a small amount of igneous rocks. The study is of great theoretical and practical significance for an analysis of the tempo-spatial distribution of sandstones of the Yanchang Formation in the northeastern Ordos basin, evaluation of favorable hydrocarbon accumulation areas and arrangement of further hydrocarbon exploration in the study area.