| 摘要: |
| 针对CO2强化页岩气开采新技术中CO2-CH4二元混合气体在页岩层中的渗透特性变化的问题，选取四川盆地下志留统龙马溪组页岩试样，基于自主研发的“三轴渗流实验系统”，开展不同配比的CO2-CH4二元混合气体在2类地应力条件下的渗流试验.试验结果表明：保持二元气体混合比例恒定，页岩渗透率随气体压力的增加而减小；保持气体压力恒定，页岩的渗透率随二元气体混合比例的改变而变化，纯CO2时渗透率最低，纯CH4最大，在混合气中CH4浓度越低，页岩渗透率越低；在注气过程中，气体加压和卸压引起页岩喉道、孔隙产生塑性变形和吸附滞后，造成页岩渗透率的滞后. |
| 关键词: 页岩 CO2 CH4 二元气体 渗透特性 |
| DOI： |
| 分类号:P618.1 |
| 基金项目: |
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| Effects of CO2and CH4mixturebinary gas onpermeability of shale |
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Feng Cheng
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Architectural Engineering College, Guizhou Minzu University, Guiyang 550000, China
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| Abstract: |
| To investigate the influence of binary gas (CO2 and CH4) on the permeability of shale for enhancing production from shale gas and CO2 sequestration. A study on shale sample from longmaxi Formation of lower Silurian in Sichuan Basin is presented. The laboratory experiments under two types of stress and different proportion of binary gas are conducted by the system named “triaxial seepage experimental system”. The results showed that: When the mixing binary gas ratio is constant，shale permeability decreased with the increase of gas pressure; Maintaining the constant pressure, the permeability of shale will change with the changing mixing binary gas ratio; the permeability of shale with pure CO2is minimum, while the permeability of shale with pure CH4is maximum. In the mixed binary gas, the lower CH4 concentration means the lower the permeability of shale;In the process of gas injection, gas pressure and pressure relief cause shale shouted, porous plastic deformation and adsorption hysteresis, which will cause the shale permeability change. |
| Key words: shale CO2 CH4 binary gas permeability |
