中国东部陆上和海域CO2成因及运聚规律与控制因素分析

通过对中国东部陆上及海域大量地质地球化学资料的分析，重点对CO2成因及运聚成藏规律与主控因素进行了深入地探讨，并在此基础上对有利CO2分布区进行了初步预测。研究表明，中国东部陆上诸断陷盆地与东南沿海海域的东海盆地及南海北部大陆架琼东南盆地和珠江口盆地CO2气藏及高含CO2油气藏中，CO2均属典型的火山幔源型成因，其运聚富集主要受控于幔源型火山活动与沟通深部气源的基底深大断裂的导气配置作用，CO2气源主要来自地壳深部幔源火山活动伴生的大量CO2；南海北部大陆架西区莺歌海盆地CO2气藏及含CO2油气藏中的CO2，属于壳源型及壳幔混合型成因，主要受控于泥底辟热流体晚期分层分块多期的局部上侵活动与沉积巨厚海相含钙砂泥岩的物理化学作用，其运聚分布具多期和分层分区的特点。因此，根据不同成因类型CO2运聚成藏规律，可以追踪气源，分析和预测天然气尤其是CO2的运聚分布，评价其资源潜力，为天然气勘探部署及决策提供依据，降低勘探风险。

Analysis of the genesis and migration and accumulation of CO2 and controlling factors in the onland and offshore areas of eastern China

According to a wealth of geological and geochemical data,this paper focuses on the genesis and characteristics of migration and accumulation of CO2 and their key controlling factors in eastern China and its sea areas and on that basis a preliminary evaluation of the favorable CO2 distribution areas is made.The study shows that in various continental downfaulted basins in eastern China, the China East Sea basin of the southeast sea region and the continental shelf-Qiongdongnan basin and Zhujiangkou basin-of the northern South China Sea,CO2 in CO2 reservoirs and CO2-rich oil/gas reservoirs is of typical volcanic mantle-derived type and that its migration and concentration is mainly controlled by mantle-derived volcanism and gas-conducting distribution of deep basement faults connected with the gas source at depth. CO2 is mainly sourced from substantial amount of CO2 associated with mantle-derived volcanism at the deep level of the crust. CO2 in the CO2 reservoirs and CO2-rich oil/gas reservoirs in the Yinggehai basin on the continental shelf of the northern South China Sea is of crust origin and crust-mantle mixing origin and mainly controlled by local,layer-by-layer and zone-by-zone, multiple intrusion of late hydrothermal fluids in mud diapir areas and physico-chemical processes of very thick Pliocene-Miocene marine calcareous sandstone and mudstone. Therefore according to the characteristics of migration and accumulation of different genetic types of CO2, we can trace the CO2 source, analyze and predict the migration,accumulation and distribution of gas and especially CO2 so as to provide a basis for make the plan and decision of gas exploration and reduce the risk of exploration.