低渗透孔隙-裂隙介质气体非线性渗流运动方程

已有的煤层气渗流研究基于达西定律，而实验表明低渗透介质气体渗流为非线性流。采用实验、理论与计算相结合的方法建立低渗透孔隙-裂隙介质气体非线性渗流运动方程。实验结果表明，低渗透孔隙-裂隙介质气体渗流曲线是从较低压力梯度下的凹形曲线至较高压力梯度下的直线，是连续变化的曲线，直线延长线不通过坐标原点，存在拟启动压力梯度。根据该普遍特征，建立了非线性渗流运动方程。其参数量纲与物理意义清楚，运动方程计算的理论曲线与实验结果吻合很好，达西定律是运动方程的特例，运动方程可运用于低渗透孔隙-裂隙介质气体渗流理论及开发计算研究。

Law of Gas Nonlinear Flow in Low Permeability Pore-fissure Media

Existing researches on coal bed methane is based on Darcy's law.But experiments show that gas flow in low permeability porous media is nonlinear.Methods of experiment,theory and calculation were used to establish a new nonlinear flow law.Experiment results of gas flow in low permeability pore-fissure media were analyzed.Universal characteristics of the flow were generalized.The relationship between flow velocity and pressure gradient is a continuous curve which changes from a hollow curve under a low pressure gradient to a line under a high pressure gradient.The line is extended but does not stretches to the origin so that a starting pressure gradient appears.A new law of nonlinear flow was established according to the characteristics.Dimension and physical meaning of parameters of the new law are clear.Results indicate that there is a good agreement between the new law and the experiment of gas flow in low permeability pore-fissure media.Darcy's law is just a special case of the new law.The new law can be used in theoretical and practical research on the gas flow in low permeability pore-fissure media.It lays the foundations of researches on mechanisms of coal-bed gas flow and provides development of coal-bed gas resources with new basis.