考虑气相动态变化的泡沫油数值模拟研究

Numerical simulation and analysis of foamy oil in consideration of the gas dynamic processes

目前中外部分稠油油藏在冷采过程中出现了不同于常规溶解气驱的生产特征,泡沫油是导致该现象的主要原因。前人主要通过改进常规溶解气驱模型模拟泡沫油现象,未考虑泡沫油油藏生产过程中的气相动态变化过程。为此,引入气相相态变化率来表征压力衰竭开采过程非平衡特性,建立泡沫油动态数学模型,并通过压力衰竭实验对模型进行验证,进而研究相关参数对泡沫油的影响规律。研究结果表明,压降速度越大,泡沫油采收率越高;气相衰竭系数越小,泡沫油产量曲线凸起越大,泡沫油产量越多;气泡生长指数越大,形成泡沫油的时间越晚。

A number of heavy oil reservoirs show anomalously good primary performance under cold heavy oil production.Foamy oil behavior is believed to be the main reason.Previous numerical simulation of primary depletion in foamy oil reservoirs is still based primarily on empirical adjustments to the conventional solution gas drive models.While these models do not involve the gas dynamic processes in foamy oil flow.This paper presents a numerical model including the non-equilibrium rate processes of the foamy oil.The model was tested by the primary depletion experiment and investigates the effects of various process parameters on oil recovery.It was observed that higher oil recovery was predicted under higher pressure decline rate.The maximum volume of the oil decreases as the gas decay coefficient A,increases.And the greater the bubble growth index b is,the later the foamy oil forms.