欠压实区内岩性油藏幕式成藏机制分析

在欠压实区的某些特定范围内，岩性油藏的形成过程具有典型的幕式特征，有效烃源岩的幕式排烃和烃源岩区内砂岩体的幕式聚烃是两个相对独立但又彼此联系的过程。幕式排烃的通道主要是烃源岩自身发育的微裂缝和由于构造运动而产生的、沟通有效烃源岩与砂体之间联系的断层。微裂缝排烃和断层排烃具有两种不同的动力学特征和排烃机制。只有排烃过程与聚烃过程协调一致，才能完成欠压实区内岩性油藏的幕式成藏过程。

MECHANISM ANALYSIS ON EPISODIC PETROLEUM ACCUMULATION OF LITHOLOGIC RESERVOIR IN UNDERCOMPACTION REGION

The forming of lithologic reservoir is episodic in the special range of undercompaction region. The episodic hydrocarbon - expulsion in the effective source rock and the episodic hydrocarbon - filling in the sandstone which are two processes relatively independent and connected with each other. The episodic hydrocarbon - expulsion has two pathways. One is the microfracture which is formed in the source rock, the other is the fault which is created by tectonic movement and it combines the effective source rock with the sandstone. There are different dynamic characteristics and hydrocarbon expulsion mechanism between the microfracture and the fault hydrocarbon - expulsion. Only when the process of hydrocarbon expulsion coordinates with the process of hydrocarbon filling, can the episodic petroleum accumulation of lithologic reservoir in the undercompaction region accomplish.