论文部分内容阅读
下切谷是由河流体系响应于海(湖)平面相对下降而向盆地方向延伸所形成的深切水道,其在油气藏的形成过程中扮演着重要的角色.为了揭示乌南斜坡区南屯组下切谷发育特征及其在油气成藏中的作用,本文对下切谷的地震反射特征、充填物垂向沉积序列及岩性进行了识别和分析,认为乌南斜坡区南屯组发育多期下切谷,其在地震反射外形上表现为顶平底凹的对称或不对称的“U”字形或“V”字形特征,垂向沉积充填序列表现为多期砂泥复合充填,且下切谷内外存在明显差异.乌南斜坡区南屯组下切谷主要发育在乌南斜坡区的缓坡部位,在平面上呈近南北向的条带状展布,沿物源方向下切谷的沉积存在“顺源堆积”的充填模式.在油气成藏方面,下切谷内的顺源砂体可形成油气藏,且控制着区块的整体含油性.下切谷也可形成侵蚀不整合,作为遮挡条件控制局部地区形成2种类型的油气聚集.
Undercut valley is a deep channel formed by the river system extending to the basin in response to the relative decrease of the sea (lake) plane, which plays an important role in the formation of the reservoir.In order to reveal the undercut valley of Nantun Formation in Wunan Slope Area, Development characteristics and their role in oil and gas accumulation. In this paper, seismic reflection characteristics of undercut valleys, vertical sedimentary sequence and lithology of fillings are identified and analyzed. It is considered that Nantun Formation in Wunan Slope Region has multiple periods of undercut valleys, The shape of the seismic retroreflection appears as symmetrical or asymmetric “U” or “V” shape features on the top and bottom concave. The vertical sedimentary filling sequence is characterized by multi-period sand and clay compound filling, There is a clear difference.The lower cutting valley of Nantun Formation in Wunan Slope Area mainly develops in the gentle slope part of Wunan Slope area and distributes in strip form near the north and south direction in the plane and the deposition of cutting valleys along the source direction exists Source accumulation. "In the aspect of hydrocarbon accumulation, the Shunyuan sandbody in the lower cutting valley can form oil and gas reservoirs and control the overall oiliness of the block. The lower cutting valley can also form erosion unconformity and control the local as a blocking condition Two types of areas are formed Type of hydrocarbon accumulation.