A Laboratory-Scale Numerical Investigation of the Effect of Confinement Conditions on the Mechanical Responses of Coal under Various Saturation Conditions
A Laboratory-Scale Numerical Investigation of the Effect of Confinement Conditions on the Mechanical Responses of Coal under Various Saturation Conditions
复制标题
封闭条件对不同饱和条件下煤体力学响应影响的室内数值研究
DOI：
10.3390/pr11113224
复制
发表时间：
2023-11
期刊：
影响因子：
3.5
通讯作者：
Huping Wang;Zhao Wang;Sanqing Ding;Chao Jin;Xiaogang Zhang;Langtao Liu
中科院分区：
文献类型：
--
作者：
Huping Wang;Zhao Wang;Sanqing Ding;Chao Jin;Xiaogang Zhang;Langtao Liu
深部煤层通常是二氧化碳封存的首选，在此期间，所涉及的饱和流体和高应力条件会显著改变煤的力学属性。为了了解应力条件对二氧化碳封存过程中煤的力学性质的影响，建立了有限元模型，并用实验数据进行了验证。结果表明，随着围压从0增加到30 Mpa，煤的强度从饱和5 Mpa的10.35%增加到8 Mpa+水饱和的114.54%，这是由于孔隙率的降低。然而，随着膨胀的减小，这种影响随着围压的增加而减弱。本研究确定的临界围压约为20兆帕，在此临界围压下，所有试件的破坏强度相似(约48.50兆帕)。此外，外加应力引起的强化效应在CO2饱和的样品中尤其明显，特别是在那些饱和了超临界CO2和Co2+水的样品中。这表明，饱和流体吸附导致的煤强度降低可以被外加应力引起的强度增加所抵消。上述结果突显了向深部煤层注入高压超临界二氧化碳用于固碳目的的有效性。
Deep coal seams are generally preferred for CO2 sequestration, during which the saturation fluids and high-stress condition involved can significantly alter the mechanical attributes of coal. To understand the effect of stress conditions on the mechanical properties of coal during CO2 sequestration, a finite element model was developed and subsequently validated using experimental data. The results indicate that coal strength increases from 10.35% for a 5 MPa CO2-saturated sample to 114.54% for an 8 MPa CO2 + water-saturated sample as the confining pressure rises from 0 to 30 MPa, due to reduced porosity. However, this effect diminishes with higher confining pressures as dilation decreases. The critical confining pressure determined in this study is approximately 20 MPa, at which all samples exhibit similar failure strength (around 48.50 MPa). Moreover, the strengthening effect caused by applied stress is especially pronounced in CO2-saturated samples, particularly in those saturated with super-critical CO2 and CO2 + water. This suggests that the reduction in coal strength resulting from the adsorption of saturation fluids can be counterbalanced by the strength gain resulting from applied stress. The aforementioned results highlight the effectiveness of injecting high-pressure super-critical CO2 into deep coal seams for carbon sequestration purposes.