淮北朱仙庄矿构造煤孔隙结构及其分形表征研究

Pore structure and fractal characteristic of tectonic coals from Zhuxianzhuang coal mine in Huaibei coalfield

基于压汞法对淮北朱仙庄矿的构造煤孔隙发育特征进行了研究,采用Menger海绵模型对样品的渗流孔和扩散孔发育特征进行了研究。研究结果表明:构造对孔隙结构的改造作用随着孔隙尺度的减小而减弱,煤体结构变形增强,大孔和中孔的孔容增幅显著,过渡孔孔容有一定程度的增加,微孔孔容变化很小,孔隙结构变得复杂;分形维数对构造煤孔隙结构特征和煤体变形特征具有良好的表征作用,随着煤体变形增强,分形维数呈增大趋势,脆性变形阶段分形维数缓慢增大,样品分形差异逐渐变大,韧性变形阶段,分形维数显著增加,样品分形差异性相对减小。随着分形维数的增加,样品的孔容和孔隙度呈指数增大趋势;渗流孔的孔容比呈负指数形式减小,扩散孔的孔容比线性增大,分形维数D<3.1时渗流孔所占比重高,随分形维数增大扩散孔孔容所占比重逐渐超过渗流孔;渗流通道增多,气体吸附能力增强,煤储层的渗透率往往减小。

Pore structure of tectonic coal in Zhuxianzhuang mine southern Huaibei coalfield was studied with mercury intrusion method. Menger sponge model was used to study the characteristics of seepage holes and diffusion holes. Results show that,the effect to pore structure from tectonism weakens with the decrease of scale,with the gradual increase of coal deformation degree, macro- pore and meso- pore volume increases significantly, transitional- pore pore volume increases,while micro- pore volume changes very little,pore structure becomes complicated; fractal dimension has good applicability to the study of tectonic coals＇ pore structure characteristics and deformation characteristics. With the increase of coal mass deformation,fractal dimension tends to increase; fractal dimension slowly increases in brittle deformation stage and sample fractal difference becomes larger,while fractal dimension significantly increases and sample fractal difference relative decrease in ductile deformation phase. With the increase of fractal dimension,pore volume and porosity index increase; pore volume ratio of seepage hole decreases negative index,pore volume of diffusion pore increases linear; seepage hole has a higher proportion when D 3. 1,the proportion of the diffusion hole pore volume gradually exceed seepage hole pore volume; Seepage channel increases,gas adsorption capacity strengths,coal reservoir permeability is often reduced.