Full Scale Pore Structure Of High Rank Coals In The South Of Qinshui Basin And Its Flow Difference

Fluid flow difference of coal reservoir is general the result of multi-model of pore structure.Based on the basic characteristics of high rank coal,high pressure mercury intrusion porosimetry,cryogenic liquid nitrogen and CO2 adsorption isotherm are applied to characterize the full scale pore distribution and establish the full scale pore structure model,furthermore,the effects of these two aspects on fluid flow difference are discussed.The results show that pore systems at various levels are all developed,and have the highest pore specific surface area in high rank coals,especially in the development of ultramicropores compared with NO.1 anthracite and quartz sandstone of the same particle size,microtransition pores are developed in NO.1anthracite and all levels of pore systems in quartz sandstone are poor developed.Through Research shows that the splicing size is 100 nm between the pore distribution of high pressure mercury intrusion porosimetry and cryogenic liquid nitrogen by using the difference of pore fractal dimension,and realizes the full scale pore system's splicing,finds three pore structure models.Total volume or pore specific surface area of full or separate scale pore system increases with the increase of vitrinite and fixed carbon content,and the decrease of particle size,inertinite,mineral substance and ash yield content,and the same is adsorption capacity,but there is no significant relationship between adsorption capacity and volatile yield.VL increases with the increase of total pore volume and pore specific surface area in different test methods.With the decrease of particle size,VL increases from 31.55 to 47.41cm3/g,PL decreases volatility from 1.07 to 0.49 MPa.With the increase of vitrinite content,effluent water increases first and then decrease;with the increase of inertinite content,effluent water decreases but influx water increases;the water's flow difference in enhanced with the increase of ash yield,total pore volume and micro-transition pore volume,the decrease of fixed carbon content;with the increase of wet angle,effluent water increases but influx water fluctuate acutely.