摘要
火山岩的脱气实验和对昌德东CO2气藏气源的分析结果表明:加热火山岩到250℃时,脱出挥发分总量为0.0299～0.0790mL/g,其中CO2脱出量为0.0218～0.0706mL/g(0.429～1.387wt%);挥发组分以CO2为主,还含有H2、CO、CH4等还原性气体,以及少量低碳烷烃,CO2含量和总烃呈现反比关系;基性岩的CO2脱出量、脱出率高于中、酸性岩;CO2脱出量与岩石碱质含量正相关。松辽盆地北部昌德东CO2气藏成藏模式为“自生自储”,成藏CO2气主要来自深部被火山岩吸附的气。随岩浆上升,在岩浆冷凝成火山岩的过程中被吸附于火山岩的节理、劈理和晶体位错之中的CO2气,连同火山岩包体中的残留气,成为高纯CO2气藏的主要补给源,并非地幔气体沿大断裂上来直接充注成藏。
Degassing experiments of volcanic rocks and gas source analysis of the Changdedong CO2 reservoir show the following： at temperature of 250℃, the degassing amounts of volatiles from volcanic rocks range from 0.0299 to 0.0790 mL/g, of which the CO2 amounts are 0.0218 to 0.0706 mL/g （viz. 0.429-1.387wt%）; the volatile components consist predominantly of CO2 with reducing gases such as H2, CO and CH4 and minor low-carbon alkanes, and there are an inverse relationship between the CO2 content and total hydrocarbon content, a negative correlation between the CO2 degassing amount and SiO2 content and a positive correlation between the CO2 degassing amount and alkali content of rocks; the amount and rate of CO2 degassing from basic rocks are higher than those of intermediate and acid rocks. The genetic model of the Changdedong CO2 reservoir is ＂self-generation and self-accumulation＂, and the CO2 gas is mainly CO2 derived from the depth and adsorbed by volcanic rocks. With the ascent of magma, the CO2 adsorbed on joints, cleavages and crystal dislocations of volcanic rocks in the process of cooling and solidification of magma into volcanic rocks, together with residual gases in inclusions of volcanic rocks, become the main recharge sources of high-purity CO2 gas reservoirs. So the CO2 gas reservoirs are not formed by direct tilting of mantle gas into the reservoirs along major faults.
出处
《地质通报》
CAS
CSCD
北大核心
2005年第10期962-967,共6页
Geological Bulletin of China
基金
国家自然科学基金项目(编号:40472074
40172072)
国家重点基础研究规划项目(编号:2001CB209133)资助
关键词
火山岩
吸附CO2气
脱气实验
昌德东CO2气藏
volcanic rocks
adsorbed CO2 gas
degassing experiment
Changdedong CO2 reservoir
