地震与洪水作用触发湖盆重力流沉积的识别与差异性研究：以鄂尔多斯盆地长7段为例

触发机制是影响重力流沉积特征的一个关键因素，而地震与洪水作用是湖盆中最重要的两种重力流触发机制。目前少见基于触发机制分类的湖盆重力流沉积特征分析，对多种触发机制共存下的重力流沉积分布模式也鲜有研究，主要原因为触发机制识别困难。本申请项目以鄂尔多斯盆地延长组长7段为对象，利用岩心、露头、分析测试等资料，在高精度层序地层格架内通过对沉积时期古地震史与古气候的恢复，基于湖盆沉积外部控制因素与沉积物内部标志性特征相耦合的方法，识别长7段中不同触发机制形成重力流沉积的分布与沉积特征，探索相似湖盆背景条件下由触发机制控制的重力流沉积模式与微相展布的差异性。进一步，将成果与储层评价联系起来，揭示由沉积模式指导的、具有预测性的长7段深水沉积中优质储层的展布情况。本申请项目有助于加深湖盆中触发机制与沉积响应对重力流沉积特征与储层质量控制作用的理解，为湖相重力流研究与深水沉积油气储层预测提供一个新的视角。

Trigger mechanism is a key factor to influence the sedimentary characteristics of gravity flow deposits. In lacustrine basin, earthquake and flood are the two main mechanisms to trigger sediment gravity flow. So far, the research on depositional features of lacustrine gravity flow deposits based on the trigger mechanisms is really rare. It is also scarce to see studies on the distribution pattern of gravity flow deposits which are related concurrently to various types of trigger mechanisms. The main reason for this situation is the difficulty to decide the trigger mechanism. This research focus on the 7th member of the Yanchang Formation, Ordos Basin. Based on data such as cores, outcrops and testing data, the high-resolution sequence stratigraphic architecture of the study interval can be built, and the paleo-earthquake history and paleoclimate characteristics can be reconstructed. Here we purpose a new way to identify the trigger mechanisms of sediment gravity flow to further analyze their influences on sedimentary characteristics and distribution pattern of the gravity flow deposits in the 7th member by linking the analysis results of extrabasinal controlling factors of lacustrine sedimentation and the iconic sedimentary features of gravity flow deposits related to various trigger mechanisms. The outcome is helpful to evaluate the differences of depositional model and facies distribution pattern of gravity flow deposits formed due to different trigger mechanisms in the same lacustrine setting. Furthermore, combining the research on reservoir evaluation, the distribution of high-quality reservoirs in deep-water deposits in the 7th member can be revealed. This research promotes understanding of the relationships between the trigger mechanism and response model of sediment gravity flows and the sedimentary characteristics and reservoir quality of their deposits in lacustrine setting, and affords a new perspective on studying lacustrine sediment gravity flows and reservoir prediction of lacustrine deep-water deposits.