深盆气藏的界定及地质特征研究

DEFINITION OF DEEP BASIN GAS ACCUMULATION AND ITS GEOLOGICAL CHARACTERISTICS

国外已发现的深盆气藏储量巨大 ,且出现于盆地构造的向斜中心、构造深凹陷部位以及斜坡下倾带 ,在赋存方式上具有一系列特殊表现。解剖深盆气藏的成藏机理、建立其发育模式并预测其发育特征是对深盆气藏进行研究的基础。从深盆气藏的特殊性分析入手 ,将深盆气藏界定为致密储层中与源岩相连的有根状气水倒置关系气藏。深盆气藏的基本地质特征是 :构造简单 ,断裂带、裂缝及微裂缝不发育 ;气源岩分别有海、陆相暗色泥、页岩、煤系地层、碳酸盐岩或其共同组合 ;无区域底水和边水存在及在此基础上形成的气水倒置 ;流体压力异常 ;

Being of a series of special existing characteristics, deep basin gases always occur in the central part of synclines, deeper part of depressions and lower part of structural incline of basins with giant reserves. Features of deep basin gases are the foundations for dissecting their formation mechanism, establishing their evolution models and distinguishing their types from the normal gas accumulation. Beginning with the specialty analysis on this kind of gas accumulation, the deep basin gas reservoir is defined as the accumulation formed in tight sands with converted distribution of fluids, and it fundamentally is concerned with their source rocks. The general characteristics of deep basin gas accumulations are discussed and studied systematically. The result of this paper will be actively useful for the exploration of the accumulations in China.