基于液氮吸附法对煤的孔隙特征研究与应用
Study and application of coal pore features based on liquid nitrogen adsorption method
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摘要: 为了探讨煤微孔隙孔径分布特征和孔结构特征,结合不同变质程度煤及不同煤体结构煤的液氮吸附试验结果,对煤的孔隙特征和液氮吸附—脱附曲线特征进行了分类研究,并将分类结果与煤储层评价结合进行了综合研究。研究结果表明:煤的液氮吸附曲线属于BET分类方案的Ⅱ型吸附等温线。依煤的孔径特征将液氮吸附曲线划分为3类:以微孔为主的A1类;以微孔和小孔为主的A2类;以微孔、小孔、中孔为朱的A3类。同时,据煤的孔隙类型将煤的液氮脱附回线划分为3类:D1型以一端开口的孔为主;D2型以孔径小于4 nm的一端开口孔为主,大于4 nm以两端开口的孔和墨水瓶孔为主,同时含有少量的一端开口的孔;D3型主要为狭窄的缝形孔。在煤层气勘探开发有利区预测时应该首选A2D3型煤储层,在煤层气含量相同的情况下应该首选A3D3型煤储层。Abstract: 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.