论硫化氢生成的地质条件

根据硫化氢的赋存环境、组成特征和热还原反应模拟试验等,提出硫化氢生成需具备五项基本地质条件:(1)地层中富含石膏;(2)富含还原剂—烃类物质;(3)较大埋深或较高的地温条件;(4)地层水作为介质和反应场所;(5)严密的封存体系。热还原反应必须在有水条件下才能进行,硫酸盐水解后的硫酸根是硫化氢的直接供体。硫化氢的生成实际经历了一个天然气向地层水的溶入和脱出过程,两者的密切关系造成含硫化氢天然气通常出现在气-水界面附近,密封条件极好的岩性气藏或构造气藏当中,构造低部位或气藏下倾方向。但是,后期构造抬升有可能造成硫化氢与地层水的分离。

Geological Conditions of Generating Hydrogen Sulphide

Based on the occurrence environment,the components and simulated thermal reduction reaction experiment of generating hydrogen sulphide,it is proposed that five necessary geological conditions for hydrogen sulphide generation are:⑴ abundant gypse that exists in layers; ⑵abundant hydrocarbon reductant; ⑶ relatively deep burial depth or relatively high geothermal temperature; ⑷ formation water as medium and reaction house; and ⑸ the closed seal system. The most important one of them,which has been ignored yet,is that proceeding of thermal reduction reaction must be in water,and only sulphur in sulphuric acid root hydrolyzing from sulphate is the direct supplier that generates hydrogen sulphide. Formation of hydrogen sulphide is a processing that the gas might dissolve into formation water and then escape from it. Because of the closed relationship between the both,the hydrogen sulphide-bearing gas is commonly present near the gas/water interface,in the excellently sealling lithologic or structural gas reservoirs,and in structurally lower places and downdip direction. However,separating of the hydrogen sulphide-bearing gas from the formation water will probably happen as structures uplift after.