凝析气藏气液相变三区扩展模型研究

推导了凝析气藏因气液相变引起凝析油聚集的新模型,以便在分析评价凝析气井产能时能正确反映凝析油聚集规律及对渗流的影响.目前,对凝析油气的流动、堵塞问题的研究是将反凝析现象引起的凝析油气流动分为3个区,但是没有给出三区的变化规律.从理论上对凝析气藏衰竭开发过程中的三区变化规律进行了严格的推导,得到衰竭开发过程的三区扩展模型.计算结果表明,该新模型能够正确预测三区扩展规律,利用三区扩展和缩小的规律,对正确评价凝析气井的产能具有指导意义.

Study on three-region extending model of gas-liquid phase change in condensate gas reservoirs

Retrograde condensate will accumulate near well-bore and plug the percolation flow passages of condensate gas when production pressure is lower than dew-point pressure in the depletion development process of condensate gas reservoirs, which will decrease the effective permeability of condensate gas and therefore reduce the productivity of condensate gas wells. At present, the flow of condensate and gas in condensate gas reservoirs caused by retrograde condensation are divided into three regions for studying the flow and plugging of the condensate and condensate gas. In this paper, the variation laws of three regions in the depletion development process of condensate gas reservoirs are closely derived, and the models of the three regions are obtained. A case shows the models can accurately predict the extending laws of three regions. The extending laws can be used for correctly evaluating the productivity of condensate gas wells.