渤海湾盆地深层潜山储集层中H_2S成因及其地质意义

Origin and petroleum geologic significance of hydrogen sulfide in the reservoir of deep buried-hills, Bohai Bay Basin

近年来深层潜山和潜山内幕成为渤海湾盆地油气勘探的重点层系之一。钻探过程中不断发现深层潜山碳酸盐岩中产出浓度较高的H_2S气体。这种H_2S气体是碳酸盐岩地层中的硫酸盐与烃类物质发生热化学还原作用形成的,H_2S浓度之所以较高,是封闭条件极好致使其无法逸散。存在浓度较高的H_2S气体,说明深层潜山碳酸盐岩内确实发生了显著的油气运移和聚集过程,具备了油气成藏的地质条件,同时表明目的层处于高温高压的封闭环境,有利于油气的保存,此外H_2S的形成对碳酸盐岩储集层的发育也有一定贡献。

The deep buried-hills became one of the important exploration focuses in the Bohai Bay Basin recently. The drillings suggest that a significant content of hydrogen sulfide accumulated in condensate oil or gas carbonate reservoir. According to the subsurface environment and evolution history of deep buried hills, and the homogenization temperature of liquid inclusions in fracture infillings of carbonate reservoir, the hydrogen sulfide could be derived from a thermo-chemical sulfate reduction (TSR). The occurrences of hydrogen sulfide show a credible process of petroleum formation and migration, and an occlusive environment with high temperature and pressure, which is in favor of petroleum preservation, especially, the condensate oil or gas. The oxidation or dispersion of hydrogen sulfide could be significantly increased by sulfuric acid dissolution, which is an efficient way to enhance the physical property of deep buried carbonate reservoirs.