雾化液滴掺混稠油的实验和数值模拟研究

稠油开采过程中,由于稠油的黏度较高和流动性差,掺稀降黏是近年来使用的主要技术手段之一。为达到稀油较为均匀的分布效果,该文提出将一个气体辅助式雾化喷嘴安装在模型套筒一侧的方法,使得稀油液滴雾化并与稠油进行掺混,通过实验和数值模拟的方法,重点研究液滴在二次破碎雾化后的物理性质,模拟雾化的滴变化后形成的液膜与底部的液压油的掺混过程,同时给出了掺稀携带量的变化规律。结果表明,液滴速度减弱后聚并现象加强,在整个流场内形成较为均匀分布的液膜和液滴,同时底部多相掺混搅动降低了混合液的黏度,当通过10.8 m3/h的气雾化1.08 m3/h的水,最终可以携带底部2.92 m3/h的油,大大提高了携带效率。研究结果验证了雾化液滴掺混稠油方法的可行性和实用性

Investigation into atomization spray blending property in heavy crude oil extraction under laboratory conditions

In this study, the atomization blending property for heavy crude oil extraction was systematically investigated both numerically and experimentally. In the experiment conducted, the blending behavior was simulated using hydraulic oil and spray with 1:10 light phase-gas atomize volume flow rate ratio in an equipment sharing the same scale as the on-site production. A Malvern Insitec droplet size analyzer was applied for the droplet size measurement, and a quick closing valve method was applied for the phase fraction measurement. A numerical simulation combined with a population balance model and the RNG k-&epsilon; model was performed under both the corresponding operating conditions and a high-pressure drop environment to further investigate the blending procedure. The results show that the atomization spray blending performs better than the equivalent pure gas lifting method with more crude oil carried at the exit. Under 0.6m3/h light phase inlet conditions, spray blending brings 8% more heavy crude than gas lifting, and the improvement rises as inlet flow rate increases. Both a droplet and liquid film are present in the casing space before blending for the spray liquid phase. In addition, the light phase droplet diameter decreases with an increase in the inlet flow rates in the lifting pipe after blending. Moreover, the blending behavior differs under various light phase inlet flow rates, while the mixture viscosity is reduced by 50% for the atomization spray method. Each of these factors was shown to be beneficial for refining the blending used in a heavy crude oil extraction technique.</p

稠油开采中新型井下混配器降黏携带特性研究

井下稠油掺稀是高效开采稠油资源的一种有效方法，为此，结合旋流生成技术和拉瓦尔喷管原理设计了一种新型井下混配器。通过开展系统的数值模拟工作，揭示了该种新型混配装置的降黏携带特性随操作参数的变化规律。研究结果表明：轴向启旋和切向开孔诱导反向旋流的设计理念可有效实现稠油和稀油的掺混，降低稠油黏度，促进稠油开采；该种混配器的降黏和稠油举升携带效果受稠油入口-总出口、稀油入口-稠油入口的压差影响，降低总出口压力、提高稀油入口压力有助于降低混合黏度，提高掺稀比和降黏比。最后建议结合产量要求和输送需求合理设置工况，减少稀油用量的同时提高开采量，降低输送黏度。研究结论可以为提高稠油开采产量提供理论参考

Research on Critical Liquid-Carrying Model in Wellbore and Laboratory Experimental Verification

Liquid loading in gas wells may slash production rates, shorten production life, or even stop production. In order to reveal the mechanism of liquid loading in gas wells and predict its critical flowrates, theoretical research and laboratory experiments were conducted in this work. A new model of liquid-film reversal was established based on Newton&rsquo;s law of internal friction and gas&ndash;liquid two-phase force balance, with the critical reverse point obtained using the minimum gas&ndash;liquid interface shear force method. In this model, the influences of the pipe angle on the liquid film thickness were considered, and the friction coefficient of the gas&ndash;liquid interface was refined based on the experimental data. The results showed that the interfacial shear force increases by increasing the liquid superficial velocity, which leads first to an increase of the critical liquid-carrying gas velocity and then to a decrease, and the critical production also decreases. With 0&deg; as the vertical position of the pipeline and an increase of the inclination angle, the critical liquid-carrying velocity first increases and then decreases, and the maximum liquid-carrying velocity appears in the range of 30&ndash;40&deg;. In addition, the critical liquid-carrying gas velocity is positively correlated with the pipe diameter. Compared with the previous model, the model in this work performed better considering its prediction discrepancy with experiment data was less than 10%, which shows that the model can be used to calculate the critical liquid-carrying flow rate of gas wells. The outcome of this work provides better understanding of the liquid-loading mechanism. Furthermore, the prediction model proposed can provide guidance in field design to prevent liquid loading.</p