加注天然气稠油高温高压条件下井筒流动特征

Wellbore flow characteristics of heavy oil injected with natural gas at high temperature and high pressure

针对塔河稠油举升困难技术难题,采用高温高压井筒模拟可视装置,研究油气两相井筒举升过程中不同温度、压力、气油比对流动型态的影响,通过电阻探针研究不同油气两相流动型态下的电阻探针频谱信号特征,建立可视与电阻探针与流动型态的关联关系,建立不同温度、压力下油气两相流动型态特征图版。结果表明:温度升高,小粒径的流型如泡状流等易转变为大粒径流型如弹状流、段塞流等,压力对流型的影响规律与温度相反;稠油加注天然气降低举升压降的主要机制为溶解降黏和密度降低;油气两相不同流型下总举升压降由小到大排序为泡状流<弹状流<蠕状流<段塞流<环状流;泡状流时油气混合流体降低举升压降效果最好,在实际生产过程中应尽可能使流型分布在泡状流状态。

Due to the technical issue of heavy oil lifting hardly, the influence of temperature, pressure and gas-oil ratios on the flow pattern of heavy oil gas two-phase flow in the wellbore was investigated by a high-temperature and high-pressure wellbore simulator with a visual cell. The spectrum signal characteristics under different oil-gas two-phase flow patterns were studied through the resistive probe. And the relationship between images, signal characteristics of the resistive probe and flow patterns was established. Also, the oil-gas two-phase flow pattern maps under different temperature and pressure conditions were proposed. The results show that flow patterns with small bubble size, such as bubbly flow, can easily change into those with larger bubble size, such as slug flow and plug flow. The influence of pressure on flow pattern is opposite to that of temperature. The pressure loss gradient of oil-gas mixture under different flow patterns can be ranked as bubbly flow<slug flow<creep flow<plug flow<annular flow. The total pressure gradient is the lowest under bubbly flow which is conductive to the oil production. The oil-gas bubbly flow pattern should be kept as much as possible in the wellbore during oil production.