深水盆地中多边形断层的几何特征与形成机制探讨

多边形断层是指一种在平面上呈多边形具有微小断距的张性断层系。自1994年被提出以来, 已有十余年的研究历史, 并在世界50多个被动大陆边缘盆地中被识别出来。研究多边形断层需要高精度的3D地震资料。我们根据琼东南盆地3D地震资料并利用相干切片技术, 首次在琼东南盆地南部发现了多边形断层, 并对其进行了初步研究。多边形断层的成因机制是前期多边形断层研究的重点, 许多学者认为深水沉积物早期压实脱水体积收缩形成的; 也有学者认为重力扩展控制断裂的发育。岩石物性、成岩作用及构造应力是影响多边形断层发育的重要因素。多边形断层对深水盆地的油气储集体的性质和分布; 以及油气、天然气水合物的运移和聚集有着重要的意义。 

THE GEOMETRICAL CHARACTERISTICS AND FORMATION MECHANISM OF POLYGONAL FAULTS IN DEEP-WATER BASIN

Polygonal fault system is a tensional fault system with small throws.Because of their polygonal shape on plan,they are named polygonal faults.They have been studied for more than ten years since they were defined in North Sea in 1994,and from then on,they have been recognized in more than fifty passive basins worldwide.Research on polygonal fault needs high-resolution 3D seismic data,so,until now no research on polygonal fault has been made in China.The mechanism of polygonal fault is the focus of preliminary studies.Many experts think that the volumetric contraction induced by syneresis during the early-stage compaction of fine sedimentation is the mechanism for the development of polygonal fault systems.Many polygonal faults formed in continental slope,so some scholars believe that gravitational spreading is the mechanism for the polygonal fault formation.Polygonal faults affect the attributes and distribution of deep-water hydrocarbon reservoir which provide pathway for fluid,so they are important for migration and accumulation of hydrocarbon and gas hydrate.