首先推导了气藏水平井产能公式 ,在推导过程中考虑了天然气的非达西流动和气层各向异性等因素对水平井产能的影响。其次是建立了气藏内流动模型、水平井井筒内流动模型、水平段最优长度数学模型 ,在建立模型过程中考虑了水平段内摩阻损失和流动状态对水平井产能的影响。所得到的方法对计算气藏水平井产能和设计水平段长度具有指导意义。 Firstly, the productivity formula of horizontal wells in gas reservoirs is deduced. In the process of derivation, the influence of non-Darcy flow of natural gas and anisotropy of gas layers on horizontal well productivity is considered. Secondly, the flow model in the gas reservoir, the flow model in the horizontal wellbore and the mathematical model of the optimal length of the horizontal section are established. The influence of the frictional loss and the flow state in the horizontal section on the productivity of the horizontal well is considered in the model establishment. The obtained method is of guiding significance for calculating horizontal well productivity and design horizontal section length of gas reservoir.