凝析气液变相态微观渗流机理研究

EXPERIMENTAL STUDY ON GAS-LIQUID POROUS FLOW MECHANISM WITH PHASE CHANGE OF CONDENSATE RESERVOIRS

在深层高压凝析气藏衰竭开发过程中,当压力低于露点压力时,反凝析油会在井筒附近聚集,堵塞凝析气的渗流通道,降低凝析气相对效渗透率;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损耗能量,降低产能。从实验和渗流理论上对凝析气藏衰竭开发时反凝析过程中气液固的渗流机理进行了研究,通过高温高压条件仿真微观可视化模型模拟了地层凝析气液固流动,直接观测了凝析油气流动特征,研究了凝析油气运移机理和流动方式,揭示了凝析油充填孔隙角隅和孔道、小孔隙充满连续流动、大孔道为溪状流以及凝析液为贴壁流和溪流的规律。

Clearly understanding of the forming, distribution and flow mechanism ot condensate near well bore can apply important theoretical basis for condensate gas reservoir development. In this paper, 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 difficuhy 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,