Research on the effective gas drainage radius of coal seam gas based upon the three-dimensional fluid-solid coupled model
In order to predict the effective gas drainage radius of coal seam gas in coal mine gas control,basing upon the fluid-solid coupled model,a three-dimensional geometric model of gas extraction is established to approach the actual site conditions.Taking the actual parameters of gas extraction in a certain coal mine as an example,COMSOL software is used to simulate the three-dimensional cloud map of gas pressure distribution along the borehole diameter at different extraction times.According to the simulation results,the effective extraction radius is determined based upon the critical value of gas pressure(0.74 MPa),and verified on site.The results show that there is a positive correlation between the effective extraction radius and the gas extraction time.The simulated effective extraction radius value has a relative error rate which is less than 10％,comparing to the measured value on site,the result indicates great accuracy.Due to the complexity of on-site measurement of effective extraction radius,this numerical simulation method can be used to predict the effective extraction radius,which has theoretical guidance significance for underground gas control drilling gas extraction and reasonable arrangement of drilling spacing.
gas extractionborehole drilling along seameffective extraction radiusfluid-solid coupled modelcritical gas pressure
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