考虑气液两相流的凝析气井生产动态研究

Production Performance of Condensate Gas Wells Considering Two-Phase Fluid of Gas and Liquid

凝析气藏开发中,反凝析液析出常常不可避免,由此造成储集层渗流表现出与干气或常规溶解气驱流动不同的特性。目前大多采用单相气或折算方法来进行凝析气井的流入动态预测,理论和现场应用表明,这类方法会带来较大的误差,因其忽略了凝析液析出对气相相对渗透率的影响。尽管众多学者对此进行了大量的理论研究,但由于模型过于复杂或是缺乏严格、全面的理论描述,均限制了其应用。以油气两相渗流的基本理论为基础,可以给出拟稳态形式的流入动态方程,同时还可以对储集层参数分布计算进行严格理论证明。实例应用表明,采用提出的油气两相流入动态方程有助于正确评估凝析气井产能,准确把握储集层动态。

Retrograde condensed liquid tends to being dropped out during development of condensate gas reservoirs, thus showing different flowing characteristics between reservoir percolation and dry gas drive or depletion gas drive. Up to now, most predictions of in-flow performance of a condensate gas well are based on single-phase gas reduced method. However; theoretical and field application indicate that such a method may give rise to greater errors owing to ignoring the effect of retrograde condensed liquid precipitation on relative permeability to gas. Although substantial theoretical studies have been made, its application still is restrained by its complexity and/or absence of strict/overall theoretical description. This paper, on the basis of oil-gas two-phase percolation theory, presents equation of pseudo-steady state in-flow performance and strict verification of calculations of reservoir distribution parameters. Applied cases show that adopting this equation of two-phase in-flow performance could help more proper estimation of condensate gas productivity and recognition of the reservoir performance.