First discovery of the sandy debris flow from the Triassic Yanchang Formation, Ordos Basin
First discovery of the sandy debris flow from the Triassic Yanchang Formation, Ordos Basin
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发表时间：
2009
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通讯作者：
Ma Yu-hu
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作者：
Ma Yu-hu
在大量岩心资料、野外观察分析和地震层序解释的基础上，鄂尔多斯盆地古湖心深水区三叠系延长组长6段发育桑迪泥石流、典型浊积岩和滑塌等多种类型，其中以桑迪泥石流为主，而典型浊积岩的分布范围有限。桑迪泥石流的识别表明，以往对延长组深水沉积的研究可能高估了浊流沉积。进一步研究表明，坡折带是控制桑迪泥石流等深水沉积-重力流砂体分布和储集性能的主要因素。总体上，上斜坡好于下斜坡，缓坡好于陡坡，因此桑迪泥石流最易生油，典型浊积岩A段中等含油，滑塌差。
Based on the large amount of the core data, field observations and analysis as well as seismic sequence interpretation, three kinds of sediment-gravity flows ( the sandy debris flow, the classic turbidite and the slumps ) were identified from the Chang 6 member of the Triassic Yanchang Formation in the deepwater area at the center of the ancient Ordos Basin lake, of which the sandy debris flow is dominant, whereas the classic turbidite is limited in distribution. The identification of sandy debris flow indicates previous study about deepwater sedimentation of the Yanchang Formation might overrate the turbidite sedimentation. Further study suggests that the distribution and the reservoir character of the deep water sediment-gravity flows sand bodies such as sandy debris floware mainly controlled by the slope break. In general, the upper slope is better than the lower slope and the ramp is favorable than steep slope and consequently, sandy debris flow is the best oil prone, classic turbidite A section is moderate oil bearing and the slump is poor.