层序地层体制中的陆相储层发育规律

沉积基准面旋回变化控制着陆相层序地层的形成与演化 ,并为预测陆相储层的发育与展布提供了一个参照格架。在纵向上 ,基准面旋回通过控制物源区的扩大与收缩、河流地貌的改造与变迁、沉积物的供给型式等 ,控制着储层形成条件与发育规律。基准面低位期是形成各类储集砂体和岩性圈闭的有利时期 ;在平面展布上 ,储层沉积作用受到古构造和古地理格局的制约 ,盆地内局部高地影响着水系的具体分布格局 ,古山口、侵蚀沟谷、古河道等决定着物源的搬运通道 ,古断层、古斜坡和坡折带等决定着沉积物卸载场所。因此 ,沟谷、河道等负向地貌单元与古断层、坡折带等地势梯度变化带相匹配的地理空间 ,是储集岩分布的有利所场。

THE REGULARITIES OF FORMATION AND DISTRIBUTION OF RESERVOIRS IN SYSTEMS OF CONTINENTAL SEQUENCE STRATIGRAPHY

The sedimentary base\|level cycle changes could control the formation and evolution of continental sequence stratigraphy, and act as reference framework for the prediction of reservoirs. Base\|level changes restricted formation condition and vertical distribution of reservoir through affecting expansion or contraction of source area, transformation of river morphology, and changes of pattern of sediment supply. Reservoir and lithologic traps could be easily formed in lower base\|level or lower parts of sequence units. In laterally, sedimentation of reservoir could be affected by the systems of paleostructure and paleotopography. Local ancient highland located in basin restricted the distribution of ancient streams. Erosional valleys and channels were mainly passageways of sediment transportation. Paleogeomorphic units such as faults, slopes and breaks on the clinaform restricted the positions of sediment deposited. Geomorphic space where negative geomorphic units produced by valley and channel matched with gradient changes of topomorphic surface, such as faults, slope breaks, are favorable positions for reservoir distribution.