考虑凝析气藏相变作用的数学模型

Mathematical model concerning facies change action in condensate gas reservoir

凝析气藏作为一种特殊的复杂气藏, 在开采过程中, 凝析油气体系在地层渗流过程中伴随着复杂的相变。凝析气藏的相变特性会导致储层内油气饱和度的变化, 从而影响和改变气体渗流的特性。在前人研究的基础上, 认真分析各区渗流特点, 考虑“凝析气、液相变作用、非达西效应、热交换、相速度及流体性质”等因素, 引入非达西因子及由于相变产生的毛管力、表面张力, 提出了表征凝析气藏多相高速流相变渗流特征模型方程, 同时考虑汽化潜热及流固热耦合, 推导出流固热耦合能量方程, 建立了多孔介质中考虑凝析气藏相变作用的渗流数学模型。

Condensate gas reservoir is regarded as one kind of complicated gas reservoir. In the course of its production,condensate petroleum system is accompanied with complex facies change during formation filtration. The change can result in the alteration of petroleum saturation within the reservoirs, thus the characteristics of gas filtration can be influenced and changed. On the basis of previous physical division, the properties of each filtration region are studied, at the same time,concerning the factor of facies change action of condensate gas and fluid,non-Darcy effects, thermal exchange,facies velocity,fluid properties and so on,non-Darcy factor and capillary driving force and surface tension caused by facies change are introduced,and the model equation characterizing facies change features of high-speed multiple facies flowing fluid in condensate gas reservoir is put forward. Meanwhile considering latent heat of vaporization and the thermal coupling between fluid and solid,the energy equation of thermal coupling is deduced, finally the filtration mathematical equation of facies change action in the porous medium of condensate gas reservoir is set up.