考虑稠油黏度影响的潜油电泵模拟与优化

CFD Simulation and Optimization of Electric Submersible Pump Considering the Effect of Heavy Oil Viscosity

刘永辉 谢在香 周宇驰 彭振华 刘重伯

LIUYonghui XIEZaixiang ZHOUYuchi PENGZhenhua LIUZhongbo

油气藏地质及开发工程国家重点实验室·西南石油大学, 四川 成都 610500 中国石油吉林油田油气工程研究院, 吉林 松原 138000 中国石化西北油田分公司工程技术研究院, 新疆 乌鲁木齐 830011 中国石油华北油田公司工程技术研究院, 河北 任丘 062552

State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation, Southwest Petroleum University, Chengdu, Sichuan 610500, China Research Institute of Oil and Gas Engineering, Jilin Oilfield, PetroChina, Songyuan, Jilin 138000, China Research Institute of Engineering Technology, Northwest Oilfield Company, SINOPEC, Urumqi, Xinjiang 830011, China Engineering Technology Research Institute, PetroChina Huabei Oilfield Company, Renqiu, Hebei 062552, China

潜油电泵采油是目前最常用的人工举升方式之一。当应用于稠油井时，受入泵流体高黏度的影响，使潜油电泵特性曲线偏离抽水时的特性曲线，导致潜油电泵合理运行窗口变窄，因此，针对水设计的离心泵结构难以适应稠油的高黏环境。针对上述问题，基于CFD数值模拟方法，系统地进行了潜油电泵在高黏条件下增压特性的研究，结果表明，随流体黏度增加，流体流动摩擦阻力更大，流体与叶片间相互作用增大，叶轮与导轮的进出口压差减小，流速降低，流体流动状态从湍流转变为层流，叶轮及导轮内回流区域的尺寸及数量均减小。同一黏度下，离心泵扬程随排量的增加而降低；同一排量下，离心泵扬程随着黏度的增大而显著降低。基于因素分析，考虑黏度影响，进而对离心泵结构参数进行了优化设计，最优结构为：入口宽度16.6 mm，叶片数6片，出口宽度21.9 mm，叶包角60o。相比于原离心泵，在黏度为400 mPa·s，允许排量范围内，扬程最大增幅28%。

Electric submersible pump (ESP) is one of the most common artificial lift techniques. However, when it is applied to heavy oil wells, due to the influence of high viscosity, the performance curves of ESP deviates from the common ones, which caused the effective application window of ESP. Therefore, the centrifugal pump's structural parameters are designed under water flow condition, which is difficult to adapt to the high viscosity environment of heavy oil wells. In view of the above problems, based on the computational fluid dynamics (CFD) numerical simulation method, we study the pressurization characteristics of ESP under the high viscosity condition. The results show that with the increase of fluid viscosity, the frictional force increases, and the interaction effect also shows an increase trend. However, the pressure difference between the impeller inlet and the diffuser outlet decreases, which leads to the flow rate decrease. Meanwhile, the flow regime inside ESP changes from turbulent flow to laminar flow, and recirculation flow area inside the impeller and diffuser blades decrease. Under the same viscosity condition, the head of centrifugal pump decreases with the increase of displacement. Under the same liquid flow rate, the head of centrifugal pump decreases significantly with the increase of viscosity. Based on factor analysis, by taking the effect of viscosity into consideration, the structural parameters of the centrifugal pump are optimized. The optimal structures are as follows: inlet width is 16.6 mm, blade number is 6 pieces, outlet width is 21.9 mm, and blade inclusion angle is 60o. Compared with the original centrifugal pump, when the viscosity is 400 mPa·s, under the submersible electric pump works in allowable flow rate range, the maximum increase of head is 28%.

10.11885/j.issn.1674-5086.2021.04.13.06