煤层气吸附量动态变化模型研究  

Adsorption dynamic model of coalbed methane

作　　者：王向浩 王延忠 刘坤[2] 张磊 林中月 

机构地区：[1]神华地质勘查有限责任公司,北京102211 [2]中国石油勘探开发研究院廊坊分院,河北廊坊065007

出　　处：《煤田地质与勘探》2015年第5期39-43,共5页Coal Geology & Exploration

基　　金：国家科技重大专项课题(2011ZX05034-05;2011ZX05042-03)

摘　　要：基于吸附势理论、气体状态方程,建立了煤储层压力与煤体吸附半径、孔隙半径与煤体吸附量、储层压力与煤体吸附量之间的关系模型,得出储层压力、吸附量、孔隙半径等多参数耦合的煤层气吸附量动态变化模型,利用潘庄区块煤体结构测试数据以及等温吸附试验结果对模型进行了验证。结果表明:潘庄区块以孔径小于7.7 nm的微孔为主,以孔径7.7 nm为临界点孔容呈先减小后增大趋势;模型计算的吸附量动态变化结果与煤体空气干燥基等温吸附变化结果在趋势上具有较高的一致性,模型的起始点为枯竭压力以及枯竭吸附量,得出潘庄区块枯竭吸附量为3 m3/t。模型不仅能够计算地层条件下不同温度和压力共同作用下煤体对甲烷气体的吸附量,且能够预测煤层气排采过程煤层气吸附量的动态变化,有助于确定煤层气排采工作制度以及提高煤层气采收率。Based on adsorption potential theory and gas state equation the model of the relationship between the coal reservoir pressure and coal adsorption radius, the model of the relationship between pore radius and coal adsorption capacity and the model of the relationship between reservoir pressure and coal adsorption amount are established, finally obtaining multi-parameter dynamic coupling change model which conclude reservoir pressure and adsorption capacity and pore radius. The model was verified by the use of coal structure testing data in Panzhuang block and isothermal adsorption test results. The results show that micropores whose pore size is less than 7.7nm are the majority in Panzhuang block. By critical point of pore size 7.7nm the pore volume decreased firstly and then increased. Calculation results of the model and isothermal adsorption curve of air-dried coal have high consistency, the starting point of the model is exhausted pressure and adsorption, the exhausted adsorption of Panzhuang block is 3m3/t. The model can not only calculate the adsorption of coalbed methane under the conditions of different temperature and pressure, but also predict the dynamic change of the adsorption during the production, these can improve the working system and recovery factor of coalbed methane.

关 键 词：煤层气 储层压力 孔隙半径 吸附量 枯竭压力 枯竭吸附量 动态变化 模型 

分 类 号：P618.11[天文地球—矿床学]