内蒙古商都地区CO2气藏地质条件研究

本文以商都盆地第三系CO2气成藏条件研究为目的，通过对区域构造（断裂、火山活动、岩浆作用）和地层特征及沉积相研究，结合地震勘探成果、CO2碳同位素、氦同位素分析成果，系统探讨了商都盆地CO2气源、运移通道、储集条件、圈闭及盖层条件，并对CO2气成藏模式进行了分析。认为：该区CO2气为幔源成因气，通过包兰哈达－高勿素深断裂运移到第三系储集层中富集成藏。第三系河流或冲积扇沉积的粗碎屑岩广泛分布，而且厚度较大，成岩程度低，具有良好的储集条件。新第三纪晚期的湖泛沉积，形成了巨厚的泥页岩盖层。沉积期后的差异压实作用、断裂、火山及岩浆活动等多因素作用，使这一地区局部构造发育，形成岩性－构造圈闭或构造性圈闭，有利于CO2气成藏。

Research on CO2 gas pool-geological conditions in Shangdu area, Inner Mongolia

This paper is aimed at researching on the Tertiary CO 2 gas pool forming conditions in Shangdu basin, by means of analyses for regional structures (fractures, volcanicities, magmatism), stratigraphic characteristic and sedimentary facies as well as results of the sesmic exploration, Carbon isotope of CO 2 and helium isotope; and conditions of the source, migratory pathway, reservoir, trap, capping bed of CO 2 gas and forming model of CO 2 gas reservoir have been discussed in the paper It is considered that CO 2 gas in this area, passing through the Wulanhada Gaowusu deep fault into Tertiary reservoir bed, comes from the mantle and then has been enriched The coarse clastic rock in Tertiary river deposits(or alluvial fan) is so widespread, thick and lower in diagenesis degree that it has favorable condition for reservoir; and the late Neogene lacustrine deposits are turned into very thick mudstone capping beds The postdepositional compacting, fracting, volcanism and magmatism and so forth caused local structures in the area well developed and formed some litho structural or structural litho traps , which are favorable for CO 2 gas reservoir forming