Modeling of mine gas emissions
- 作者：D.P.AdhikaryH.GUO
- 会议时间：2011-05-14
- 关键词：Coal mining ; gas emission ; numerical modeling ; COSFLOW
- 作者单位：CSIRO Earth Science and Resource Engineering,PO Box 883,Kenmore,QLD,Australia 4069
- 母体文献：中国工程科技论坛第118场——2011国际煤矿瓦斯治理及安全会议论文集
- 会议名称：中国工程科技论坛第118场——2011国际煤矿瓦斯治理及安全会议
- 会议地点：合肥
- 主办单位：中国工程院
- 语种：chi
摘要
This paper describes a three-dimensional numerical model,called COSFLOW.It uses a Cosserat continuum approach for the efficient description of mechanical stress changes and deformation in weak layered rock,typical of coal measures.This mechanical model is coupled with a two-phase dual porosity fluid and multi-component gas flow model to describe flow of water and gases through porous rock,desorption of gases from the matrix and subsequent flow of water and gases through the fracture network.The coupling includes simulation of permeability and porosity changes with rock deformation.Further the rock mass consisting of many interconnected fractures is idealized as an equivalent porous continuum using an equivalent anisotropic hydraulic conductivity matrix defined in terms of mean fracture spacing and mean aperture.This formulation is amenable to easy evaluation of modifications to the hydraulic conductivities as a function of stress induced changes in fracture aperture.The numerical code is used to simulate gas emission in an Australian coal mine.The numerical model uses geotechnical and hydrogeological data obtained from the mine site to calibrate the model input parameters.Many parameters in the model are not directly measurable and must be inferred by back-analysis of existing deformation,stress and hydrological data obtained during previous mining.The calibrated model then can be used to make predictions for future mining panels.The model used measurements of gas production from predrainage boreholes for calibration and provided accurate predictions of average gas emissions into the longwall panel and post-drainage boreholes,although transient fluctuations were seen in the measurements.These were probably caused by local variations in geology or gas content or other factors not incorporated in the model.