辽河西部凹陷曙光-雷家地区隐蔽油气藏主控因素及分布规律

Main Factors Controlling Hydrocarbon and Distribution Rules of Subtle Reservoirs in Shuguang-Leijia Area of Western Sag of Liaohe Oilfield

辽河西部凹陷曙光—雷家地区成藏条件优越,油气资源丰富,发育潜山油气藏和古近系特殊岩性体油气藏。结合地质背景分析,对隐蔽油气藏的主控因素和分布规律进行了系统研究。研究结果表明,该地区隐蔽油气藏主要受构造—沉积环境、有效烃源岩、断层、不整合及砂体输导层等几个因素控制,其中构造—沉积环境控制了潜山和特殊岩性体的形成。平面上隐蔽油气藏围绕生烃洼陷展布,纵向上沿断层或不整合面分布;主要生储盖组合决定隐蔽油气藏的分布层位;在洼陷带、斜坡带和凸起带这3个不同构造区带,发育的隐蔽油气藏成藏模式不同。

The formation conditions are favorable and hydrocarbon resources are abundant in Shuguang-Leijia area of the western sag of Liaohe Oilfield.Subtle reservoir types are mainly the buried hill reservoirs and the Palaeogene special lithologic reservoirs.Main factors controlling hydrocarbon of subtle reservoirs and their distribution rules in the area are studied systematically with the analysis of the geologic setting.The result shows that the subtle reservoirs in the area are mainly determined by such factors as the structural-depositional environment,valid source rocks,fault surface,unconformity surface and sandbody transporting layers,etc.Formation of the buried hills and special lithologic rocks are primarily controlled by structural-depositional environment.The distribution of subtle reservoirs is horizontally around generating sags.Subtle reservoirs are vertically distributed along by fault surface and unconformity surface.The distribution set of subtle reservoirs is controlled by some main source-reservoir-cap assemblages.Formation models of hydrocarbon accumulations of subtle reservoirs tend to vary in three different tectonic settings including sags and slopes as well as uplifts.