区域性盖层在油气聚集与保存中的作用

Effect of Regional Caprocks in Oil and Gas Accumulation and Preservation

根据区域性盖层的发育特征，从不同侧面对其在油气聚集与保存中所起的作用进行了深入分析，认为区域性盖层通常是阻止游离相油气逸散的良好区域物性屏障；如果其欠压实，具异常孔隙流体压力，它还可以成为阻止水溶相油气逸散的区域压力屏障；如果其再具生烃能力，还可以成为阻止扩散相天然气逸散的区域浓度屏障。油气藏形成后，区域性盖层又可成为阻止地表水淋滤和细菌氧化对油气藏破坏的区域保护层。

According to the development characteristics of regional caprocks,great efforts have been made to analyse the effect of it on oil and gas accumulation and preservation in different aspects. We consider regional caprocks to be the good barriers to prevent oil and gas in free phase from escaping. If uncompacted and possessing abnormal pore fluid pressure,regional caprocks are the barriers to prevent oil and gas in water dissolving phase from escaping. If it owns the ability of generation gas again,regional caprocks are the barriers to prevent gas in diffusive phase from escaping. After oil and gas pools were formed, regional caprocks became the protecting layers to prevent the leaching of surface water and bacterial oxidation from destorying the oil and gas pools.