二氧化碳成因、成藏主控因素及脱气模式研究综述

高纯度的CO_2气藏不仅具有重要的资源意义,同时也有很重要的地质意义,CO_2气藏成因及主控因素研究已成为世界范围内地球科学领域广为关注的重要课题。对CO_2气藏的成因、鉴别方法、成藏主控等进行了系统的论述。结果表明:CO_2气藏的成因可以分为无机成因和有机成因,且以前者为主;CO_2气藏成因的判别主要是综合多种地球化学指标,结合天然气成藏地质条件来分析;高地温场、深大断裂和岩浆活动是CO_2气运聚成藏最重要、最直接的三大主控因素;幔源CO_2进入沉积盆地中具有4种脱气模式,即沿岩石圈断裂直接脱气模式、热流底辟体脱气模式、壳内岩浆房-基底断裂组合脱气模式和火山岩吸附气后期脱气模式。但在CO_2对油气运移聚集的影响、CO_2释放机理、脱气模式等方面的研究尚存一定的争议,将是未来主要的研究方向。

Reviews on CO2 genesis, controlling factors of hydrocarbon accumulation and degassing model

High purity CO2 gas reservoir not only has important resource significance, but also has very important geological significance. CO2 geological problems have become an important topic in the field of Earth Science worldwide. In this paper, the origin and identification method of CO2, the controlling factors of hydrocarbon accumulation and the model of CO2 degassing are systematically discussed. The results show that: the genesis of CO2 can be divided into inorganic origin and organic origin, and inorganic CO2 gas is the main one in nature; the identification of CO2 genesis is mainly based on the combination of various geochemical identification indexes and geological conditions of natural gas accumulation; high temperature field, deep fault and magmatic activity are the three most important and direct controlling factors of CO2 gas migration and accumulation; mantle derived CO2 migration and accumulation are the most important and direct factors There are four degassing modes in the sedimentary basin, i.e. direct degassing along lithospheric faults, thermal diapir degassing model, magmatic chamber basement fault combination degassing mode, and late stage degassing of adsorbed gas from volcanic rocks. There are still some controversies about the influence of CO2 on hydrocarbon migration and accumulation, CO2 release mechanism, degassing mode and so on, so further research and exploration are needed in the future.