珠江口盆地新近系地层岩性圈闭形成条件及发育规律分析

Formation conditions and development features of Neogene stratigraphic-lithologic traps in Pearl River Mouth Basin

伴随勘探程度的提高,地层岩性圈闭已经成为珠江口盆地油气勘探的重要新领域。为此,对珠江口盆地新近系这一主力含油层段进行了地层岩性圈闭形成条件和发育规律的分析。认为盆地新近纪以来多期次的海平面升降旋回,多种沉积体系的共同发育,2种类型坡折及其对应的低位体,以及2次构造运动为地层岩性圈闭的发育创造了十分有利的条件。在上述条件的综合作用下,地层岩性圈闭的发育呈现出陆架区、坡折区各具特色、层序界面附近层段最为有利、油气运移通道是成藏主控因素等规律性特征。

As exploration degree increases, stratigraphic-lithologic traps have become an important new field for oil and gas exploration in the Pearl River Mouth Basin. The formation conditions and development features of Neo-gene stratigraphic-lithologic traps were systematically investigated in this study. The basin has experienced several stages of sea level fluctuations ever since Neogene, resulting in the coexistence of multiple sedimentary systems. Two types of shelf edges and the corresponding low stand systems tracts as well as two significant tectonic move-ments provided favorable conditions for the development of stratigraphic-lithologic traps, which showed obviously different features in the continental shelf region and the shelf margin region. The intervals near to sequence boundary seem to have the most favorable potential. Oil and gas migration pathways play important roles in con-trolling final hydrocarbon accumulation.