注液态CO2开采天然气水合物实验研究
Experimental research on injection of liquid CO2 for exploiting natural gas hydrates
靳鸿铨 1赵建忠 1牛晓明 2张驰 1高强3
作者信息
- 1. 太原理工大学 原位改性采矿教育部重点实验室,山西 太原 030024
- 2. 太原市生态环境监测与科学研究中心,山西 太原 030002
- 3. 太原科技大学 安全与应急管理工程学院,山西 太原 030024
- 折叠
摘要
注液态CO2开采天然气水合物既能安全采出CH4又能原位固碳.为揭示开采过程中CO2相态对水合物储层的影响规律,采用水合物三轴渗透实验装置,在NaCl体系中,以石英砂为多孔介质,注入CH4气体生成甲烷水合物,以此模拟天然气水合物储层.在4.5 MPa的孔隙压应力下,分别研究了注液态CO2开采对甲烷水合物分解行为的影响,反应温度对注液态CO2开采甲烷水合物的影响,以及反应温度对注液态CO2开采甲烷水合物后储层水合物饱和度的影响.结果表明,注液态CO2开采对甲烷水合物的分解有促进作用,反应温度为8.0℃、反应压力为4.5 MPa时,相较于降压法开采,注液态CO2开采CH4采出量提高了22.81%,CH4采出率提高了13.66%.在液态CO2环境中,高的反应温度有利于甲烷水合物分解,相较于6.0℃,反应温度为10.0℃时CH4采出量提高了40.41%.与CO2水合物生成时释放的热量相比,高的反应温度在促进水合物分解中占主导作用.随反应温度升高,CO2封存量、转化率和开采后储层水合物饱和度均降低.反应温度为6.0℃和10.0℃时,CO2封存量分别为0.1962 mol和0.1034 mol,CO2转化率分别为22.08%和11.86%,开采后储层水合物饱和度分别为57.91%和34.21%,较平均初始饱和度(41.72%)分别提高了38.81%和降低了18.01%.注液态CO2开采天然气水合物对提高CH4采出量和采出率,以及促进CO2封存具有积极作用.
Abstract
Injection of liquid CO2 for exploiting natural gas hydrates can safely produce CH4 while sequestering carbon in situ.To reveal the influence of CO2 phase states on hydrate reservoirs during extraction,a triaxial hydrate penetration experimental apparatus was used.In a NaCl system,quartz sand served as the porous medium,CH4 gas was injected to form methane hydrate,simulating natural gas hydrate reservoirs.Under a pore pressure stress of 4.5 MPa,the effects of liquid CO2 injection on the decomposition behavior of methane hydrate,the impact of reaction temperature on methane hydrate extraction by liquid CO2 injection,and the influence of reaction temperature on the post-extraction hydrate saturation of the reservoir were studied,respectively.The results show that injection of liquid CO2 promotes the decomposition of methane hydrate.At the reaction temperature of 8.0℃and the reaction pressure of 4.5 MPa,compared with the depressurization method,injection of liquid CO2 increases CH4 production by 22.81%and the recovery rate by 13.66%.In a liquid CO2 environment,higher reaction temperatures are favorable for the decomposition of methane hydrate.Compared to 6.0℃,the CH4 production increases by 40.41%at 10.0℃.Higher reaction temperatures play a dominant role in promoting hydrate decomposition,compared to the heat released during CO2 hydrate formation.As the reaction temperature increases,CO2 sequestration amount,conversion rate,and post-extraction reservoir hydrate saturation all decrease.At reaction temperatures of 6.0℃and 10.0℃,CO2 sequestration amounts are 0.1962 mol and 0.1034 mol,CO2 conversion rates are 22.08%and 11.86%,and post-extraction reservoir hydrate saturations are 57.91%and 34.21%,respectively,which increases by 38.81%and decreases by 18.01%,compared to the average initial saturation(41.72%).Injection of liquid CO2 for exploiting natural gas hydrates has a positive effect on increasing CH4 production and recovery rates,as well as promoting CO2 sequestration.
关键词
液态CO2/水合物开采/天然气水合物/CO2封存Key words
liquid CO2/hydrate extraction/natural gas hydrates/CO2 sequestration引用本文复制引用
出版年
2024
国家科技期刊平台
NSTL
万方数据