工业废气经脱硫注氨处理后，气体主要成分为N2/CO2。基于减少能源消耗，利用页岩储层有效封存CO2的思想，开展N2/CO2混合气注入对页岩力学特性影响规律研究。以四川省龙马溪组黑色露头页岩为试验研究对象，开展恒温恒压条件下，不同浓度配比N2/CO2混合气注入页岩试验，利用单轴压缩试验和巴西劈裂试验，分析N2/CO2混合气中CO2浓度对于页岩力学特性的影响。研究结果表明：页岩试件经N2/CO2二元混合气浸泡后，混合气中随CO2浓度的增加和相变，试件孔隙增长率呈现先增大后减小趋势，孔隙增长率为34.91%～110.6%；页岩试件的强度和泊松比先降低后增大，弹性模量先增大后降低，单轴抗压强度损失率为37.5%～69.1%，抗拉强度损失率为35.3%～85.4%，弹性模量增幅37.5%～54.7%，泊松比损失率为11.8%～20.6%；混合气中CO2浓度和相态变化对页岩损伤强度有较大影响，损伤因子先增大后降低，页岩表现出明显脆性破坏特征，主要破坏模式为劈裂破坏。初步分析表明：页岩在混合气作用下孔隙结构发生改变。当CO2为气态时，页岩吸附CO2，孔隙产生范德华力，使页岩基质膨胀，天然孔裂隙扩展，孔隙增幅加大，强度降低；当CO2为超临界状态时，混合气中SC-CO2

（超临界二氧化碳）对页岩有机矿物质溶解能力，随SC-CO2浓度增加而减弱，孔隙增幅降低，强度衰减率降低。混合气中SC-CO2浓度为11.33 mol/L时，溶解有机质能力最强，页岩孔隙度最大，脆性最高，力学性质劣化效果最明显。

After the industrial waste gas is treated by desulfurization and ammonia injection, the main component of the gas is N2/CO2. Based on the idea of reducing energy consumption and using shale reservoirs to effectively sequester CO2, the study on the effect of N2/CO2 gas injection on the mechanical properties of shale was carried out. Taking the black outcrop shale of the Longmaxi Formation in Sichuan Province as the experimental research object, under the condition of constant temperature and pressure, the N2/CO2 mixture gas injection test with different concentrations and ratios was carried out. The uniaxial compression test and the Brazilian splitting test were used to analyze the N2/CO2 effect of CO2 concentration in CO2 mixture on mechanical properties of shale. The research results show that: after the shale specimen is soaked in the N2/CO2 binary gas mixture, with the increase of CO2 concentration and phase change in the gas mixture, the pore growth rate of the specimen shows a trend of first increasing and then decreasing, and the pore growth rate is 34.91%-110.6%; the strength and Poisson's ratio of shale specimens decreased first and then increased, and the elastic modulus increased first and then decreased, the loss rate of uniaxial compressive strength was 37.5%-69.1%, the loss rate of tensile strength was 35.3%-85.4%, the elastic modulus increased by 37.5%-54.7%, and the Poisson's ratio loss rate was 11.8%～20.6%; the change of CO2 concentration and phase state in the mixed gas has a great influence on the damage intensity of shale and the damage factor increases first and then decreases. The shale shows obvious brittle failure characteristics, and the main failure mode is splitting failure. Preliminary analysis shows that the pore structure of shale changes under the action of mixed gas. When CO2 is in gaseous state, shale adsorbs CO2, and the pores generate van der Waals force, which expands the shale matrix, expands natural pores and fissures, increases the increase in pore size, and reduces the strength; when CO2 is in a supercritical state, the solubility of SC-CO2 in shale organic minerals in the mixed gas decreases with the increase of SC-CO2 concentration, the increase of pore size decreases, and the rate of strength decay decreases. When the SC-CO2 concentration in the mixed gas is 11.33 mol/L, the ability to dissolve organic matter is the strongest, the shale has the highest porosity, the highest brittleness, and the most obvious deterioration effect of mechanical properties.