多因素作用下的稠油流动界限试验

Experimental study on flow boundary of heavy oils with multiple influence factors

稠油在储层中的流动能力受温度、压力和渗透率等多重因素影响,以普通稠油和特稠油为研究对象,通过原油的黏温性和流变性测试获得稠油的反常温度点,结合岩心单相渗流试验,研究多因素影响下的稠油流动特征变化规律,并建立流度与拟启动压力梯度和启动温度的关系。结果表明:普通稠油和特稠油通过黏温关系和流变特性获得的反常温度点分别为60和80℃,在低渗、中渗和高渗岩心上发生流动状态变化的温度点分别为80、65、60℃和120、90、80℃;稠油拟启动压力梯度随着温度的升高、渗透率的增加而减小,并利用原油流度与有效驱替压力关联了两类稠油的流动状态转换区间,得到相关性良好的多因素影响下稠油的拟启动压力梯度表达式和启动温度表达式,能够更加准确的预测稠油油藏的极限泄油半径和转驱温度。

The mobility of heavy oils in reservoirs can be affected by multiple factors,such as temperature,pressure,forma-tion rock permeability and oil property and compositions.In this study,the flow behaviors of ordinary heavy oil and extra heavy oil under various reservoir conditions were investigated.The inflection temperature of different oils was obtained based on viscosity-temperature and rheology testing and the variation regularity of flow characteristics of the heavy oils influenced by multiple factors were further studied via single-phase flow experiments in cores,and the relationships between mobility and threshold pressure gradient and threshold temperature were established.The results show that the inflection temperatures ob-tained by the viscosity-temperature and rheology testing of the ordinary heavy oil and extra heavy oil are 60 and 80℃,re-spectively,and the temperatures of the altered flow-state in low permeability,middle permeability and high permeability cores are of 80,65,60℃ and 120,90,80℃,correspondingly for the ordinary oil and the extra heavy oil.The threshold pressure gradient of heavy oils decreases with the increase of temperature and permeability.Oil mobility and effective dis-placement pressure can be used to correlate the districts of the altered flow-state of different types of heavy oils,and the threshold pressure gradient and threshold temperature values affected by multiple factors were obtained with good correlativi-ty.The expression of the threshold temperature can be useful to accurately predict the limit of oil drainage radius and the temperature for displacement transition in heavy oil reservoirs.