稠油-水两相高温高压垂直管流压降规律

Flow Pressure Drop of Heavy Oil-Water Two-phase in Vertical Pipe under High Temperature/Pressure

针对深层稠油在井筒举升过程中形成油水两相混合流体造成举升困难的问题,采用高温高压垂直管流装置,实验研究了加入乳化降黏剂前后高温(30~130℃)、高压(0.1~50 MPa)条件下不同持水率稠油水两相流体的垂直管流压降规律,发现压降损失随持水率的增加逐渐增大,在相转换点附近达到最大值,发生相转换后,随持水率增加急剧降低。流速越大,压降损失越大,但当流速增大到一定值时,由于高流速下稠油的剪切变稀特性,压降增加趋于平缓。在高温高压实验数据基础上,依据前人模型,推导并修正得出稠油水两相压降计算模型,实验数据与模型拟合度达0.97以上,绘制了不同黏度稠油在不同油水比下的举升压差关系图版,为进一步精确预测含水稠油的井筒压降规律提供了新的方法。

Aiming at solving the difficult lifting problem of ultra-deep heavy oil-water two phase mixture forming during the process of fluid lifting in wellbore,a high-temperature and high-pressure vertical tube flow set was used to experimentally study the heavy oil-water two phases flow pressure drop before and after adding emulsifiers with different water cuts under high temperature(30~130℃)and high pressure(0.1~50 MPa).Results show that the pressure drop loss increases gradually with the increase in water holdup and reaches the maximum value near the phase transition point,then decreases sharply with the increase in water cut after phase transition point.The higher the velocity is,the greater the pressure drop loss will be.However,when the velocity increases to a certain value,the increase of pressure drop tends to be gentle due to the shear thinning characteristics of heavy oil at high velocity.Based on the experimental data under high temperature/pressure conditions and the existed models,an improved model of a heavy oil-water two-phase pressure drop calculation was proposed.The fitting degree between the experimental data and the model is above 0.97.A pressure difference map of heavy oil with different viscosities and oil-water ratios was also proposed,which provides a new method for further accurately predicting of wellbore pressure drop of heavy oil with different water cuts.