具有蜡沉积的凝析气藏气液固微尺度变相渗流动力学模型研究

在深层高压凝析气藏衰竭式开发过程中,当压力低于析蜡点和露点压力时,蜡和凝析油会在井筒附近聚集,堵塞凝析气的渗流通道,降低凝析气相有效渗透率;当压力低于析蜡点压力时,蜡的析出会堵塞孔隙喉道,使流动阻力增大而损耗能量、降低产能。从实验和微观动力学理论角度研究了凝析气藏衰竭式开发时的反凝析过程中气液固的流动特征。通过高温高压条件仿真微观可视化模型模拟地层凝析气液固流动来直接观测凝析油、蜡流动特征。阐述了蜡沉积运移规律和凝析油气固变化特征和输运规律。揭示了凝析油充填孔隙角隅和孔道(小孔隙充满连续流动、大孔道为溪状流)、凝析液为贴壁流和溪流的规律和凝析气液固渗流过程中蜡沉积吸附在多孔介质表面、蜡沉积随气相悬浮流动和推移流动、蜡沉积在凝析液中随凝析液流动的规律。建立了变相微尺度动力学模型方程。

DYNAMIC MODEL OF GAS-LIQUID-SOLID POROUS FLOW WITH PHASE CHANGE OF CONDENSATE RESERVOIRS

Clearly understanding of the forming, distribution and flow mechanism of condensate near well bore can apply important theoretical basis for condensate gas reservoir development. In this paper, Dynamic model of gas-liquid-solid porous flow with phase change of condensate reservoirs is founded. An effective experiment method is brought out to study distribution and flow rules of condensate near well bore region. The real porous media is modeled by the phantom micromodel with similar pore structure. The experiments were carried out in porous media under high temperature and high pressure to observe the forming, distribution and flow rules of condensate. The results indicate that the condensate accumulate easily at small pore, stagnant pore, pore throat and pore surface, which evolves to a plug gradually. It is difficulty to accumulate for the condensate in big pore. The flow manner of the condensate includes mainly three styles: schlep by gas, crawls along pore wall and plug flow.