琼东南盆地新近系坡折带特征及其对沉积体系的控制

 坡折带是层序划分样式的重要依据。大量地震剖面的精细解剖表明，琼东南盆地新近系的坡折带可以分为构造坡折带和沉积坡折带，构造坡折带进一步分为断裂坡折带和挠曲坡折带。不同的坡折带类型控制的储层沉积特征是不同的：构造坡折带的下倾方向一般发育一系列高成熟度、较高孔隙度的斜坡扇和盆底扇，是研究区较好的储集体；缓坡的沉积坡折带控制了斜坡扇裙和盆底扇的发育，陡坡的沉积坡折带控制了滑塌体的发育，沿陆坡向海方向形成了滑块、滑塌-泥石流、碎屑流-浊流的重力流演化序列。坡折带不但控制了储层的发育，而且控制形成有利的输导系统发育，坡折带及其控制的低位域砂体发育带是有利的勘探区带。

Patterns of Neogene Slope-break Zones and the Depositional System Under Their Control in Qiongdongnan Basin

The slope-break is thought to be an important indicator to distinguish the patterns of sequences. Based on a comprehensive explanation of a large number of seismic sections in the Qiongdongnan basin, the neogene slope-break can be classified into two types: structural and sedimentary slope-break zones. The structural slope-break zones can be divided further into two patterns, the fracture slope break pattern and the flexure slope break pattern. Different patterns of slope-break are related with different reservoir sedimentary models. Structural slope-break zones, which are produced by the long-term activities of syndepositional faults, have always been an important factor in the depositional sequence development and the deposition process. Along the down dip direction of structural slope-break zones, a series of basin floor fan and slope fan are usually formed, which are characterized by high maturation and relatively high porosity. Gentle sedimentary slope-break controls the development of slope fan skirt and basin floor fan. Steep sedimentary slope-break controls the growth of slip block, to form the gravity flow evolutionary series from slider, slip-debris flow to debris flow-turbidity current along the slope in sea directions. Slope-break zones not only control the development of the reservoir, but also control the formation of the favorable conducting system, and the slope-break zones and low stand sand stones under their control are the favorable exploration zones.