摘要
为了探究煤层注水过程中活性水溶液对煤体裂隙演化规律的影响,利用CT三维重建技术构建煤体微观渗流损伤模型,定量分析孔裂隙网络的连通性及形态学拓扑结构,并选用十二烷基苯磺酸钠、乳化剂OP-10、仲烷基磺酸钠以及十二烷基硫酸钠这4种表面活性剂作为研究对象进行煤体渗流损伤模拟。研究结果表明:连通孔隙多由大孔组成,孔隙当量半径集中在20~40μm,占比为88.6%,其配位数服从高斯分布,占比为68.56%;孤立孔隙中当量半径不超过10μm的孔占比为94.8%,数量随孔隙体积增大而逐渐减少,且体积不超过1000μm3的孔占孤立孔隙的69.74%。随着水压的上升,4种表面活性剂作用下煤样损伤单元数与渗流场分布范围、孔隙率与渗透率、声发射数目与能量总体都呈上升趋势,局部会因渗流运动渗流场与裂隙结构应力场之间的临界反应出现波动,且活性水溶液的密度及动力黏度制约临界反应的作用强度与范围;当水压为5 MPa左右时,动力黏度使煤样渗透率呈现不同演化趋势;当水压为11 MPa时,不同表面活性剂作用下煤样孔隙率接近,且均较原始孔隙率提升约6.63倍;当水压为9~11 MPa时,煤样声发射数目和能量与动力黏度呈反比。因此,在利用活性水溶液改善煤层注水效果时,除了合理控制水压外,还应将其动力黏度限制在较小范围内。
In order to explore the effect of surfactant on coal fracture propagation in the process of coal seam water injection,the microscopic seepage damage model of coal was constructed by using CT three-dimensional reconstruction technology,and the connectivity analysis of pore fracture network and quantitative study of morphological topology structure were carried out.Four surfactants,i.e.,sodium dodecyl benzene sulfonate,emulsifier OP-10,sodium secondary alkyl sulfonate and sodium dodecyl sulfate,were selected as the research objects to simulate the seepage damage of coal.The results show that the connected pores are mostly composed of large pores,and the equivalent radius of pores is concentrated at 20-40μm,the proportion of which is 88.6%,and the coordination number obeys Gaussian distribution,accounting for 68.56%.Equivalent radius in isolated pores shall which does not exceed 10μm accounted for 94.8%,and the number distribution has the rule of gradually decreasing with the increase of pore volume,and the pore whose volume is not more than 1000μm^(3) accounts for 69.74%of isolated pore.With the increase of water pressure,the number of damage units of coal samples,the distribution range of seepage field,porosity and permeability,the number of acoustic emission and energy show an overall upward trend under the action of four kinds of surfactants.The local will fluctuate due to the critical reaction between the seepage field and the stress field of fracture structure,and the density and dynamic viscosity of the active water solution restrict the action time and intensity of the critical reaction.The permeability of coal samples induced by dynamic viscosity presents different trends under the water pressure of about 5 MPa.When the water pressure is 11 MPa,the porosity under the action of different surfactants has little difference,and is nearly 6.63 times higher than the original porosity.The number and energy of acoustic emission of coal samples at water pressure which is 9-11 MPa are inversely proportional to the dynamic viscosity.Therefore,in order to enhance the water injection effectiveness in coal seams using active aqueous solutions,and properly control the water pressure,particular emphasis should be placed on restricting the dynamic viscosity within a narrow range.
作者
陈纪海
陈曦
毛彦军
刘子建
葛少成
CHEN Jihai;CHEN Xi;MAO Yanjun;LIU Zijian;GE Shaocheng(School of Safety and Emergency Management Engineering,Taiyuan University of Technology,Taiyuan 030024,China;School of Civil Engineering,Dalian University of Technology,Dalian 116024,China)
出处
《中南大学学报（自然科学版）》
EI
CAS
CSCD
北大核心
2024年第10期3933-3944,共12页
Journal of Central South University:Science and Technology
基金
国家自然科学基金资助项目(52174195,51704145)
山西省基础研究计划项目(20220321221061)。
关键词
表面活性剂
煤层注水
CT三维重构
裂隙扩展
渗流规律
surfactant
coal seam water injection
CT three-dimensional reconstruction
fracture propagation
seepage law
