中文摘要：

通过大量岩心观察、钻测井资料分析及野外露头观察,对鄂尔多斯盆地南部延长组长6—长7深水重力流沉积特征、触发机制、沉积过程、沉积模式及石油地质意义进行了系统分析。研究结果表明：研究区共存在滑动岩体、滑塌沉积、砂质碎屑流沉积、浊流沉积及泥质碎屑流沉积5种类型的重力流沉积物,各类型的沉积物特征明显。不同类型重力流沉积物垂向组合可分为5类,研究区重力流的形成过程可分为5个阶段：三角洲前缘沉积阶段、滑动阶段、滑塌变形阶段、砂质碎屑流及泥质碎屑流形成阶段以及浊流形成阶段。滑动、滑塌砂体多呈孤立透镜体状,砂质碎屑流砂体多以扇沟道的形式展现出来,浊流砂体多分布在扇沟道的前端或侧翼,呈席状砂展布。深水重力流砂体垂向叠置厚度大,可形成规模大的油藏,大大扩展了深湖的勘探范围。研究区长6、长7油层组砂质碎屑流砂体储集层物性较好,含油性好,是重点勘探层位。

英文摘要：

Through the observation of abundant cores,analysis of drilling and logging data,and outcrop observation,the sedimentary characteristics,triggering mechanisms,sedimentary process and pattern of deep-water gravity flow were analyzed in detail in the Chang 6-7 intervals of the Triassic Yanchang Formation,southern Ordos Basin. The results show that there are five types of gravity flow sediments,which are slipped mass,slump deposits,sandy debris flow deposits,turbidity deposits and muddy debris flow deposits. There are five vertical combination styles of gravity flow deposits in the study area. The sedimentary process of gravity flow can be divided into five stages,which are delta front sedimentary stage,slide stage,slump deformation stage,sandy and muddy debris flow stage and turbidity flow stage. Slide and slump sand bodies are formed in shapes of isolated lens; sandy debris flow sand bodies are formed in fan channel; and turbidity sand body are formed as sheet sand,mainly distributing in the front or sides of the fan channel. Sand bodies of deep-water gravity flow are vertically superposed in large thickness,which could form large scale reservoirs and extremely extends the exploration of deep lake sedimentary facies. In the study area,sand bodies of sandy debris flow in Chang 6-7 intervals are worth of great concern for their preferable physical properties and hydrocarbon potential.