鄂尔多斯盆地黄陵地区上三叠统延长组长7、长6油层组浊积岩沉积特征及地质意义*

利用岩心观察、薄片鉴定和粒度分析等方法，对鄂尔多斯盆地黄陵地区上三叠统延长组长7、长6油层组浊积岩沉积特征与油气地质意义进行了研究。研究结果表明，浊积岩主要为长石砂岩，以棱角状—次棱角状为主，粒度具有典型的浊流沉积特征。沉积构造可见泥底构造、同生变形构造、粒序递变层、鲍玛序列等。最常见的鲍玛序列有ABC型、AB型、ADE型、AE型、CDE型和A段叠置型，具备浊积岩的典型特点。识别出薄层浊积岩和中厚层浊积岩，其属于三角洲前缘滑塌成因，可分为中心微相和边缘微相。浊流砂体是半深湖—深湖区发育的良好储集体，其分布区可作为重要的油气勘探区。

Sedimentary characters and geological implication of turbidite of the Chang 6 and Chang 7 intervals of Upper Triassic Yanchang Formation in Huangling area, Ordos Basin

Based on cores,thin sections,grain size analyses,the sedimentary characteristics of turbidite and its geological significance of the Chang 7 and Chang 6 intervals of Upper Triassic Yanchang Formation have been studied systematically in Huangling area of the Ordos Basin.The study results indicated that the turbidites are angular and sub-angular arkose and has the typical characteristics of turbidite deposition according to the results of grain size analysis.The turbidites are characterized by erosion surfaces,synsedimentary deformation structures,graded sequence and the Bouma sequences including ABC、AB、ADE、AE、CDE and A overlaying models which are the typical sedimentary characteristics of turbidite.The turbidite intervals mainly include two types,one is thin bedded and the other is medium-thick bedded.The tubidites are formed by the slump sediments of delta-front and can be divided into two sedimentary facies belts,i.e.the central and marginal microfacies.Turbidity sandstone is regarded as good reservoir formed in semi-deep lacustrine to deep lacustrine environments and becomes important oil-gas exploration target.