稠油冷采泡沫油溶解气驱油藏开发动态数值模拟

Study of numerical simulation of dissolved gas reservoir for foam cold recovery of heavy oil

稠油注蒸汽等热采开发方式面临着油层出砂、气窜和采油成本高等问题,而稠油冷采过程中形成的泡沫油,则使稠油油藏具有采油速度快、采收率高和生产气油比低等特点。在论述STARS模拟泡沫油机理及模型局限性的基础上,建立了稠油冷采泡沫油溶解气驱油藏模型。模拟结果表明,与常规溶解气驱油藏相比,泡沫油溶解气驱油藏具有生产气油比上升缓慢、累积产油量高等特点;在油相中气泡形成频率一致的情况下,气泡破裂速度越快,生产气油比越大,产油量越低;原油粘度越高,地层渗透率越低,开发效果越好,稳产时间越长。

Foamy oil is a kind of crude oil containing separated little gas bubbles in the course of dissolved gas drive of heavy oil cold recovery.Foamy oil flow performs different characters form conventional oil flow during natural depletion,and its oil production is high,gas/oil ratio is low,formation pressure declines slowly and recovery is high.Many studies and models have been done and proposed,and effective model have been built by STARS simulator.In this research,the simulation mechanisms of foamy oil by STARS and its limitations are elaborated.Based on these mechanisms,foamy oil reservoir is simulated with STARS. Moreover,sensitivity analysis is conducted to analyze the effects of parameters on performance of foamy oil reservoir.The simulation results show that the higher frequency of bubbles to free gas causes higher gas/oil ratio and lower oil production,and higher viscosity of oil and lower permeability causes lower gas/oil ratio and longer stable production period.All of the work above may provide some reference to actual production of foamy oil reservoir.