Study On CBM Reservoir Physical Properties In Jurassic Huangling-longxian Coalfield

CBM is symbiotic minerals with coalbed, the main component of CBM is methanewhich is adsorbed in coalbed. CBM develop and utilize which not only can reduce the coalmine disasters and environmental pollution, but also can replace and supplement toconventional natural gas, and has great economic value, social benefit and environmenteffect.Huangling-Longxian coalfield is a key area of mining in Ordos, its stratum belong toJiaoping-Huating area in Ordos stratum, flod is development in the most area, JurassicYan`an Formation is the only coal-bearing strata. The coal of Huangling-Longxian coalfieldis low rank coal, its methane content compares with other contemporaries coalfield in Chinais obvious higher. At present, the research of low rank coal CBM is lesser in China, andCBM occurrence change rule and reservoir physical properties know lesser inHuangling-Longxian coalfield.Tha article acquires some parameters as permeability, reservoir pressure, close pressureetc in Huangling-Longxian coalfield which use injection/fall off test, obtains someparameters of the coal core which use coal petrography analysis and quality analysis, mercurytest, methane content test, adsorption test etc, revises the parameters of coalbed which usenumerical simulation method for F1block, and forecasts daily production and cumulativeproduction for F2block. The result shows that coalbed metamorphic grade is lower andbelong to Ⅱ levels of bituminous coal, the main pore is holes and microporous, methanecontent changes greatly from0.08～6.88m³/t, the main composition of gas is methane, theadsorptivity of the different kinds of coalbed distributes irregular, coalbed permeabilitychanges greatly from0.08～5.73mD and is not obvious correlation with coalbed depth, allcoalbed is low pressure reservoir, pressure gradient is from0.50×10^-3～10.03×10^-3MPa/m,reservoir pressure is correlation with coalbed depth and close pressure, the numericalsimulation reservoir parameters of F1block explain the situation of coalbed when CBM welldrain, single well daily production is expected to reach1185.80m³/d.Tha article indicates that low rank coal CBM has development value inHuangling-Longxian coalfield which after the result of analysis parameter. According to methane content, permeability, reservoir pressure, it think Ⅰblock is the best block for theexploitation of CBM. And Ⅰ block is expected to become the first low rank CBMcommercial demonstration area.