基于压汞及图像处理技术的高阶煤孔裂隙特征研究

Study on the characteristics of high-rank coal pore and fracture based on mercury injection and image processing technology

为了研究沁水盆地南部煤储层的孔裂隙特征,综合采用压汞试验、手标本描述和扫描电镜等方法对沁水盆地南部的煤样孔裂隙进行研究。结果表明:沁水盆地南部煤层微小孔比较发育,中孔和大孔比较不发育,煤样微、小孔的孔容占总孔容的63%~75%,其次为大孔,占总孔容的19%~28%,中孔孔容最不发育,表明该地区的煤层有利于煤层气的赋存,但其渗透性可能较差;该地区主要发育内生裂隙,外生裂隙不发育,4个不同矿区的煤样内生裂隙面密度从小到大分别为成庄矿、高河矿、长平矿和赵庄矿;采用裂隙张开度参数对4个矿区的煤储层渗透性进行评价,发现渗透性从小到大分别为高河矿、成庄矿、长平矿和赵庄矿。研究结果对煤层气的勘探开发具有指导意义。

In order to study the pore and fracture characteristics of the coal reservoirs in the southern Qinshui basin,the mercury injection experiment,hand specimen description and scanning electron microscopy were comprehensively used to analyze the pore and fracture of coal samples in the southern Qinshui basin.The results showed that the micropores were relatively developed in the coal seam in the southern Qinshui basin,and the mesopores and macropores were not developed,It could be seen that in the southern Qinshui basin,the micropore and small pore volume of the coal sample were most developed,accounting for 63%~75%of the total pore volume,followed by the large pore volume,accounting for 19%~28%of the total pore volume,and the middle pore volume was the least developed,indicating that the coal reservoirs were favorable to the occurrence of coalbed methane in this area,but coal reservoir permeability was poor.The area was mainly developed with endogenous fracture,and the exogenous fracture was not developed.The permeability of the coal reservoirs was evaluated by using the fracture aperture parameters in the four mining areas.It was found that the permeability from small to large was Gaohe mine,Chengzhuang mine,Changping mine and Zhaozhuang mine,respectively.The research results had certain significance for the exploration and development of coalbed methane.