珠江口盆地珠三坳陷构造反转与油气聚集

分析了珠三坳陷反转构造的演化史及沉积填充特征,识别出了该区域反转构造的样式,研究了其成藏条件。按剖面组合样式可将该区域内的反转构造划分为两种类型,即断层相关型和挠曲褶皱型。断层相关型按照反转的强烈程度又可划分为下正上盖亚型和下正上逆亚型;按照褶皱的形成机制,可以将挠曲褶皱型划分为前峰后谷亚型和前谷后峰亚型。不同的反转样式对油气聚集成藏有着不同的控制作用,其中下正上盖亚型对油气聚集成藏最为有利。以文昌19-1油气构造为典型实例,对其成藏模式进行的研究表明,晚期反转构造对油气成藏具有改造作用。

Tectonic inversion and its relationship with hydrocarbon accumulation in Zhu-3 Depression of Pearl River Mouth Basin

The tectonic evolution history and the sedimentation filling characteristics of Zhu-3 Depression were analyzed. The patterns of inversion structures in this area were recognized, and the reservoir-forming conditions were discussed. According to the patterns of profile structures, the inversion structures were divided into two types of fault correlation and bending folds. The fault correlation pattern was subdivided into the sub-type cap rock on top with normal structure underneath and sub-type reverse fault on top with normal structure underneath on the basis of the different reversal degree of reversal structures. The bending folds pattern was subdivided into sub-type peak in front with trough rearwards and sub type peak rearwards with trough in front according to the different reservoir forming reasons. The inversion structures controlled the reservoir forming conditions. The sub-type cap rock on top with normal structure underneath is the most favorable for oil and gas accumulation. The analysis of Wenchang 19-1 structure in Zhu-3 Depression proved that the inversion structures in the late stage played very important roles for oil and gas accumulation.