改进分水岭算法的煤岩孔隙重构及渗流模拟

Reconstruction of coal pore network based on improved watershed algorithm and seepage simulation

为更加真实地还原出煤的数字孔隙网络结构,模拟煤孔隙中瓦斯微观渗流过程,开展基于形态学改进分水岭算法的煤岩孔隙重构研究。首先基于改进型分水岭算法,提出识别煤基质颗粒分布参数与孔隙网络的方法,通过中值滤波和数学形态学变换降低信号噪声的影响,减少“过分割”现象;然后以5~10、10~40和40~80目粒径型煤为例,识别颗粒分布参数,构建型煤孔隙网络结构;最后基于格子玻尔兹曼方法(LBM)渗流模拟检验孔隙网络瓦斯。结果表明:改进型分水岭算法降低了噪声干扰,重建的煤孔隙结构具有较高的复杂性和连通性;利用LBM算法模拟孔隙结构渗流,能展示出瓦斯渗流速度和方向等局部细节。

In order to construct the digital pore network structure of coal to simulate the microscopic seepage process of gas in coal pores,the pore-reconstruction study of coal rock based on the morphological improvement of watershed algorithm was carried out.Firstly,a method based on improved watershed algorithm to identify coal matrix particle distribution parameters and pore network was proposed,and the noise influence was reduced by median filtering and mathematical morphology transformation to avoid the phenomenon of"over-segmentation".Then,taking 5-10 mesh,10-40 mesh and 40-80 mesh size coal as examples,the particle distribution parameters were identified and the pore network structure of the coal was established.Finally,the seepage simulation test was carried out to verify pore network gas based on the LBM.The results show that the improved watershed algorithm reduces noise interference and the reconstructed coal pore structure has high complexity and connectivity,and that the seepage simulation of the pore structure by LBM algorithm can show local details such as gas seepage velocity and direction.