Study and application of coal pore features based on liquid nitrogen adsorption method

in order to discuss the pore diameter ditibution and pore structure features of the micropore in the cal incombination with th liquid ntrogen adsopton experinent resutis with diferent metanorphic coal and different cal structure coal a classication stuty was conducted on the coal pore features and h liquid nirogen adsoption-desorption curve features and a comprehensive study was conduced on the conmbiation of the classication resuts and the coalreservoir evaleationThe study resuits showed tht th liqud ntrogen adsoption curve ofthecoal belonged to the Ⅱ mode adsorption isotherm of the BET cassication plan. According to he pore diameter features of the coal the liouid ntirogen adsoption cures could be divided to threetypes.The micropore would be A1 type mainlythe micopore and small pore would be A2 type mainly and the micropore,smal ore and medium pore woud be A3 type mainl Meanwie according to the pore type of the coal.the liqudnitrogen desorpton loop could be divided to threetypes. D1 type would mainly be a pore with one end open. D2 type with a pore diame less than 4 m would be a pore with one end open mainly and the pore with a diameter over 4 nm and with two end open and inkbotle typepore mainly and meanwile would be some pore with oneend open. 3 type mainly would be a narow sltpore. n the prediction of the coalbed metane exploration and development favorable zone.,the A2D3 type cal eseroir should be firstly selected.Under the same coalbed methane content,the A3D3 type coal reservoir should be firstly selected.