超临界二氧化碳用于地热开采的研究综述

Research Review on Supercritical Carbon Dioxide for Geothermal Extraction

分析超临界二氧化碳地热开采优势,综述超临界二氧化碳应用于干热岩、深部盐水层、枯竭油气藏地热开采的研究进展,分析面临的挑战,展望未来研究趋势。凭借自身独特的热物理性质,超临界CO_(2)比水更加适合用于非常规地热开采。干热岩的地热储量最丰富,属于典型的高温地热资源,与水相比,工作介质采用超临界CO的采热效率更高,且可避免引起地化反应。深部盐水层和枯竭油气藏均属于中低温型地热资源,分布广泛,拥有天然孔隙性储层结构,适合将CO_(2)地质封存与地热开采相结合。枯竭油气藏具有天然孔隙结构、完善的圈闭结构,可在开采地热时充分利用现有的井网和地面设施,节省投资并延长使用寿命。对于枯竭气藏,由于天然气开采一般不存在产水过程,一定程度避免了地化反应的发生,非常适合采用超临界CO_(2)开采地热。

The advantages of supercritical carbon dioxide for geothermal exploitation are analyzed,the research progress of supercritical carbon dioxide applied to geothermal exploitation in hot dry rocks,deep saline aquifers and depleted oil and gas reservoirs is reviewed,the challenges faced are analyzed,and the future research trends are expected.With its unique thermo-physical properties,supercritical CO_(2)is more suitable for unconventional geothermal extraction than water.Dry hot rocks have the richest geothermal reserves and belong to typical high-temperature geothermal resources.Compared with water,using supercritical CO_(2)as the working medium has higher heat recovery efficiency and can avoid geochemical reactions.Deep saline aquifers and depleted oil and gas reservoirs both belong to low to medium temperature geothermal resources,which are widely distributed and have natural porous reservoir structures,and are suitable for combining CO_(2)geological storage and geothermal exploitation.Depleted oil and gas reservoirs have natural porous structure and well-developed trap structures,which can fully utilize existing well pattern and surface facilities during geothermal exploitation,saving investment and prolonging service life.For depleted gas reservoirs,because natural gas extraction generally does not involve a water production process,which to some extent avoids the occurrence of geochemical reactions,it very suitable to use supercritical CO_(2)for geothermal extraction.