川西北地区三叠系硫化氢分布及运移特征研究

在深入研究包裹体岩相学特征的基础上,应用激光拉曼光谱分析了川西北地区不同层位、不同产状中包裹体的物质组成,探讨了该地区硫化氢的分布及运移特征。研究结果表明,该地区中、下三叠统中丰富的膏岩矿物、足够的埋藏深度以及较高的地温梯度构成了硫化氢大规模生成的必要条件。高含硫化氢天然气在须二段成岩作用阶段就开始大规模向该地层中运移,其运移通道主要为孔喉和溶蚀孔隙;后期注入的烃类中硫化氢含量相对较低,其运移通道为构造裂隙和流体压力作用形成的裂隙,在运移过程中相对稳定的还原环境是硫化氢不被消耗的关键条件。 

DISTRIBUTION AND MIGRATION FEATURES OF H2S IN THE TRIASSIC IN THE NORTHWESTERN SICHUAN

Based on the deep researches of diagenesis in the northwestern Sichuan,chemical composition of the fluid inclusions in different formations and different attitudes were analysed by Laser Roman Microspectrometer.And the distribution characteristics of H2S and its migration features were discussed.The results show that the charging of hydrocarbon with high H2S concentration from low formation last a long time.Hydrocarbon being charged at the stage of diagenesis of the 2nd Member of Xujiahe Formation has a high H2S concentration and its migration pathway are mainly the hole,throat and fissure system,while hydrocarbon being charged at the later stage has a relatively low H2S content and its migration pathway is mainly the fissure system.And sustained reducing environment is necessary for H2S not being exhausted during migration.