Experimental study on pore structure features of sedimentary rocks in deep coal measures by mercury intrusion porosimetry

In order to discover phy sical features of the sedimentary rockss in deep coal measures, mereury intrusion porosimetry expeni ments were conducted on 25 samples of six types of sedimentary rocks collected from two domestic deep coal mines. The differences in pore struc-ture parameters and pore distribution characteristics among sedimentary rock samples of different types and sediment ary environments were compared. The results showed that the representative pore structure parameters of different types of sedimentary rock samples have marked difference. The porosity of each type of rock increase with partice size range. Under the same sedimentary environment condition, the pore size distribution curves of the different types of sedimentary rocks have obvious difference. In general, the pore volumes of the mudstones are the smallest and their pore size distribution curves are flat. The pore volumes of the conglomerates are the largest and their pore size distribution curves are steeper. In comparison with the sandstones and mudstones, conglomerates have an evident S type pore distribution feature. Meanwhile, the dominant pores for different types of sedimentary rocks are quite different. In addition, under different sedimentary environment conditions, the pore size distribution curves of the sedimentary rock samples from the same lithological deep coal measures have obvious differences and the differences of their pore distibution features are remarkable.