多边形断层系特征及成因机制--以松辽盆地三肇凹陷为例  

Origin of polygonal fault systems:A case from the Sanzhao sag in the Songliao Basin

作　　者：丁修建[1] 柳广弟[1] 孙明亮[1] 王盘根 

机构地区：[1]中国石油大学(北京)地球科学学院 [2]油气资源与探测国家重点实验室 [3]中海油研究总院

出　　处：《石油勘探与开发》2013年第3期309-319,共11页Petroleum Exploration and Development

基　　金：国家自然科学基金项目(41102086)

摘　　要：多边形断层系主要发育于细粒沉积物中,垂向上具有层控性,平面上呈多边形形态,具有断距小、密度高、走向多方位、平面延伸长度小的几何特征。多边形断层系为非构造成因,目前认为有密度反转、脱水收缩、重力扩展、溶解作用驱动的剪切破裂等成因,溶解作用驱动的剪切破裂可能是多边形断层系最广泛的成因机制。松辽盆地三肇凹陷白垩系发育大量小规模断层,这些断层在垂向上、平面上、几何特征上均具有多边形断层特征,判断为典型的多边形断层系。三肇凹陷多边形断层系发育程度和溶解作用有关,溶解作用强的层位多边形断层系发育较多,多边形断层系可能是溶解作用引起的剪切破裂成因。三肇凹陷多边形断层系是葡萄花油层和扶杨油层油气运移的通道,对油水分布有明显的控制作用。多边形断层系和砂体均发育的区域是三肇凹陷的有利勘探区。Polygonal fault systems are mainly found in fine-grained sediments. They are controlled by layers vertically and characterized by polygonal planform geometry. They are also characterized by small thult throw, high fault density, various strikes, and small lateral extension, Their genetic mechanisms, which are usually recognized as non-tectonic, include density inversion, dewatering contraction, gravitational loading, and dissolution-induced shear failure, with the last one being dominant. Many small extensional faults have been lbund in the Cretaceous in the Sanzhao sag of the Songliao Basin. Having the characteristics of polygonal faults vertically, horizontally and in shape, they are defined as typical polygonal fault systems. There are more polygonal fault systems in the formation with heavier dissolution, these polygonal fault systems may be formed by the mechanism of dissolution-induced shear failure. Polygonal thult systems are migration pathway tbr the Putaohua and Fuyang oil layers in the Sanzhao sag and they significantly control on oil-water distribution. The areas where sandstones and polygonal fault systems are developed together are favorable exploration areas.

关 键 词：多边形断层系 几何特征 成因机制 三肇凹陷 松辽盆地 

分 类 号：TE122.2[石油与天然气工程—油气勘探]