小尺寸竖管热损失结蜡趋势数值仿真  

Numerical Simulation for Wax Forming Trend Considering Heat Loss in Small Size Vertical Pipes

作　　者：杨再广[1] 刘启伟 魏凯[2,3] 刘玉龙 韩雪龙[2,3] YANG Zaiguang;LIU Qiwei;WEI Kai;LIU Yulong;HAN Xuelong(Sinopec Xinjiang Xinchun Petroleum Development Co.,Ltd.,Dongying 257000,Shandong,China;National Engineering Research Center for Oil&Gas Drilling and Completion Technology(Yangtze University),Wuhan 430100,Hubei,China;Hubei Key Laboratory of Drilling and Production Engineering for Oil and Gas(Yangtze University),Wuhan 430100,Hubei,China)

机构地区：[1]中国石化新疆新春石油开发有限责任公司,山东东营257000 [2]油气钻完井技术国家工程研究中心(长江大学),湖北武汉430100 [3]油气钻采工程湖北省重点实验室(长江大学),湖北武汉430100

出　　处：《新疆石油天然气》2024年第4期44-49,共6页Xinjiang Oil & Gas

基　　金：中国石化胜利油田科技项目“准中深层异常高压自喷井井筒及地面配套技术研究”(YKC2202);新疆维吾尔自治区“天山英才”之优秀工程师培养计划项目“高压低渗透油藏井筒及地面配套技术研究”(2022TSYCGC0002)。

摘　　要：在油井自喷生产过程中,油流沿井筒轴向、径向方向温度梯度较高,蜡浓度径向受布朗运动、分子动力影响,存在高变化梯度。在胶质、沥青质等杂质的作用下,井筒受油流温度、环境温度等因素的影响产生析出物,轻则降低产量,重则堵塞井口,导致生产中断。针对中国西部某油田低凝点、强热敏性原油在井筒中易结蜡的问题,基于热力学模型且考虑理想溶液模型中易被忽略的潜热,建立小尺寸竖管油流结蜡有限元模型。利用数值模拟软件对井筒结蜡趋势进行仿真,并研究环境温度、油流入口温度、油流雷诺数对井筒结蜡的影响规律。研究结果表明,低凝点、热敏效应强的原油在低温环境和井筒油流低雷诺数的条件下井筒结蜡量有显著增加的趋势。为避免井筒内因热损失而造成结蜡堵塞,油流温度宜控制在高于静态析蜡点5℃至10℃范围内。研究结果可为油田开发过程中竖井结蜡趋势的预测、结蜡预防措施的制定提供理论依据。In the production process of flowing wells,the temperature gradients of oil streams are high in the axial and radial directions of wellbores,and the radial wax concentration is affected by Brownian motion and molecular dynamics,leading to highly variable gradients.Due to impurities such as resins and asphaltenes,wellbore precipitates are generated under the control of multiple factors such as oil stream temperature and ambient temperature,with consequences ranging from production reduction to wellbore blockage and thus production interruption.Given the high likelihood of crude oil wax forming with a low freezing point and high thermal sensitivity in an oilfield in western China,a finite element model of oil stream wax forming in small size vertical pipes was established based on thermodynamic model,and the latent heat often ignored in ideal solution models was incorporated.The wax forming trend in a wellbore was simulated using the numerical simulation software.The effects of ambient temperature,oil stream inlet temperature and oil flow Reynolds number on wellbore wax forming were studied.The results show that the wax deposition of crude oil with a low freezing point and high thermal sensitivity increases significantly in a low temperature environment with a low Reynolds number of oil flow.In order to avoid wax forming and blockage caused by heat loss in wellbore,oil stream temperature shall be controlled within 5-10℃higher than the static wax deposition point.The findings of this research provide theoretical support for the prediction of wax forming trend and the determination of wax forming prevention measures during oilfield development.

关 键 词：井筒结蜡 数值仿真 相平衡 热平衡 结蜡趋势 

分 类 号：TE352[石油与天然气工程—油气田开发工程]