深部流体活动对油气运移影响初探

近年来,深部流体已经成为地质学研究的一个热点,在很多沉积盆地都发现了深部流体活动的证据.当这种流体出现在沉积盆地中时,必定会对盆地的地质构造、岩石演化、流体活动和油气成藏产生重大影响,油气运移作为其中的一个重要环节也不例外.研究表明,深部流体在地幔和深部地壳以超临界态存在,这种相态的流体具有很强的溶解和扩散能力,它可以萃取和富集沉积物中的分散有机质并直接运移.其次,深部流体对生烃有显著的加氢作用,通过大量生烃而促进油气初次运移.再次,流体与围岩或储层发生物理和化学反应,可以显著改善储层的孔渗条件,促进油气二次运移.此外,深部流体熔融地壳岩石形成的火成岩可以形成盖层,遮挡油气使其聚集成藏. 

PRIMARY STUDY ON THE EFFECTS OF DEEP-SOURCED FLUID''''S MOVEMENTON HYDROCARBON MIGRATION

In recent years,research on deep-sourced fluid has become a hotspot in geology. A lot of evidences about the movements of deep-sourced fluid have been found in many depositional basins. When this fluid comes into existence in basins,it will produce great impacts on geological structures, evolution of rocks, fluid movements and accumulation of oil and gas. As a part of them, the oil and gas migration is not of exception. Researches show that deep-sourced fluid exists in supercritical state in mantle and lower crust of the earth. It can extract and enrich dispersive organic matters in sediments because of its high dissolving and diffusing capacity, and transport them. Then it can promote kerogen to generate hydrocarbon with hydrogen added, thus it can promote source rocks to expel hydrocarbons. In addition, the physical and chemical reactions between deep-sourced fluid and surrounding rocks greatly improve the porosity and permeability of resevoir, which contributes a lot to secondary migration of oil and gas. Besides, deep-sourced fluid can melt the rocks in crust to form igneous rock, and this rock can prevent the oil and gas migration to form reservoir.