淮南煤田刘庄煤矿深部煤层气地质特征

为了查明刘庄煤矿深部煤层气赋存及开发地质条件,在井田内实施了两口煤层气探井,并开展了系统的分析测试工作。结果表明:刘庄深部勘查区主要煤层孔隙度一般为4.14%~4.77%,比表面积集中在2.184~5.228m 2/g,13-1煤层、11-2煤层和8煤层试井渗透率分别为0.12mD、0.09mD和0.08mD,孔裂隙系统发育一般,属于渗透性差的储集层;储层压力梯度大于静水压力梯度,属高异常压力范畴;主要煤层兰氏压力平均为2.61MPa,兰氏体积平均为6.74m 3/t,吸附能力较低;LT-1井气测录井过程中共出现14层气测异常,异常层段全烃含量均较低,最大为3.701%(16-1煤);主要煤层的含气量分布在0.21~1.47m 3/t,平均0.65m 3/t,主要煤层含气饱和度均很低,最大值仅为18.0%。综合分析认为,刘庄煤矿深部主要煤层埋深大,孔裂隙系统发育差,渗透率低,而且具有低含气量和低饱和度的特征,煤层气勘探风险较高。

Deep Part CBM Geological Features in Liuzhuang Coalmine,Huainan Coalfield

To identify deep part CBM hosting and exploitation geological conditions in the Liuzhuang coalmine have drilled two CBM exploration wells and carried out systematic analysis and tests.The result has shown that in the Liuzhuang deep part exploration area,porosities of main coal seam are 4.14%~4.77%,specific surface areas concentrated within 2.184~5.228m 2/g.Permeabilities of coal Nos.13-1,11-2 and 8 are 0.12mD,0.09mD and 0.08mD respectively in test wells.Development of pore and fissure systems is general belonged to poor permeability reservoir.Reservoir pressure gradient is larger than hydrostatic pressure gradient and belonged to high abnormal pressure category.Average Langmuir pressure of main coal seams is 2.61MPa,Langmuir volume average 6.74m 3/t,with lower adsorptivity.During the gas logging process in the well LT-1 has total 14 gas anomalies,total hydrocarbon content of the anomalous intervals are all lower,maximum3.701%(coal No.16-1).Gas content of main coal seams is within 0.21~1.47m 3/t,average 0.65m 3/t;gas saturation of main coal seams is all low,maximum only 18.0%.The comprehensive analysis has considered that the main coal seams in Liuzhuang coalmine deep part have deep buried depth,poor developed pore and fissure systems,low permeability,low gas content and low saturation features,thus CBM exploration risk is rather high.