深部流体中氢的油气成藏效应初探

THE EFFECT OF HYDROGEN FROM DEEP FLUID ON HYDROCARBON GENERATION

深部流体对含油气盆地内油气成藏的影响已不断得到认识 ,人们在越来越多的油气田中发现了深部流体参与油气成藏的证据。氢是深部流体中重要的还原组分 ,许多沉积盆地都有氢异常的报道。深部来源的氢至少可能通过两种途径进入沉积盆地内 :一种是地球深部的氢直接通过深部脱气进入沉积盆地 ,通道为切穿盆地基底的深大断裂或伴随的火山活动 ;另一种来源是超基性岩的次生蚀变 ,如橄榄岩的蛇纹石化也可以放出氢。氢与沉积盆地内的有机质发生作用将会大大提高烃类的产率。加氢反应和合成反应是两种不同的机制。模拟实验表明在沉积盆地中存在加氢反应的条件 ,加氢反应可能是含油气盆地中广泛存在的一种生烃机制。在中国东部地区裂谷型盆地广泛地分布 ,并具有众多切穿基底的深大断裂 ,研究证实存在相当多的无机成因天然气 ,这预示着研究深部流体中氢的成藏效应不仅具有理论意义 ,而且也具有重要的现实意义。

As more and more evidences of involvement of deep fluid in reservoir formation have been found, the effects of deep fluid on petroleum generation and accumulation have been identified. Hydrogen is a main composite of deep fluid. The potential source of hydrogen in sedimentary basin is from lower crust or mantle, and it can enter basin through deep fault that cut through the basement. The other potential source of hydrogen is ultra basic rock alteration such as serpentinization. The reaction of hydrogen from deep source with organic matters in the basin can increase hydrocarbon production. There can be two mechanisms of the reaction, including hydrogenation and combination. The simulation of hydrogenation shows that the conditions for hydrogenation in sedimentary basin are possible. Hydrogenation is probably a widespread mechanism of hydrocarbon generation in sedimentary basins. There spread rift basins with many deep faults that cut through basement in East China, and many non organic origin gases have been identified already there. This means that the researches on effects of hydrogen from deep fluid on petroleum generation and accumulation are magnificent for both theoretics and oil exploration.