摘要
窄间隙环空是油气固井作业中遇到的主要挑战之一,由于环空间隙急剧减小,导致局部剖面平均流速快速增大,进而使得井底固井水泥浆的当量循环密度显著提高,从而大大增加了压漏地层的风险。文章借助计算流体力学软件Fluent对单一环空窄间隙条件下固井水泥浆的层流流动进行分析,采用直接数值模拟来验证Metzner-Reed(MR)理论方法的准确性。同时,通过分析宾汉、幂律和赫巴三种非牛顿流体流变模型对固井液当量循环密度计算结果的影响,对三款主流钻完井软件在处理不同流变模型时的适应性进行了对比分析。通过研究发现,MR法与直接数值模拟法的固井液当量循环密度计算结果基本一致,因此MR法是一种计算窄间隙条件下固井液当量循环密度更为精确的方法。此外,在窄间隙环空中,井底固井液当量循环密度的计算结果对流变模型十分敏感,而不同钻完井软件在分析不同流变模型时又具有各自不同的适应性。因此,在实际进行窄间隙固井的水泥浆设计时,基于流变特性测试数据采用最小二乘法优选水泥浆的流变模型,再根据流变模型进行钻完井软件的选择。
Narrow annulus is one of the main challenges in cementing operation for well completion.Due to rapid decease of the radial size of annulus,the local flow rate increases sharply,which triggers an increase of the equivalent circulating density of the cement slurry in downhole,and thus increases the risk of formation leakage.In this present work,the laminar flow of cementing slurry in a single annulus with narrow radial size is analyzed by the computational fluid dynamics software Fluent.And the direct numerical simulation(DNS)is used to verify the accuracy of the theoretical Metzner-Reed method.Meanwhile,in order to analyze the influences of Bingham,Power-Law,Herschel-Bulkley models on calculation of cementing ECD,three types of commercial software are used and their feasibility on different rheological model is compared.Based on this investigation,the results obtained from MR theoretical method are in great agreements with those obtained from DNS.Hence,the MR method is verified as an effective method in calculating cementing ECD even in narrow annuli.In addition,the downhole ECD is verified as sensitive to the rheological model in narrow annuli,and the commercial software have their different adaptations on the different rheological models.Therefore,in the practical design of cement slurry,the rheological model should be optimized by least square method based on the rheological property test data,and then the drilling and completion software is selected according to the rheological model.
作者
李旭
任胜利
刘文成
赵丹汇
廖茂林
林黎明
LI Xu;REN Shengli;LIU Wencheng;ZHAO Danhui;LIAO Maolin;LIN Liming(Oilfield Chemistry Department,China Oilfield Services CO.,LTD.,Langfang,Hebei 065201,China;School of Mechanical Engineering,University of Science and Technology Beijing,Beijing 100083,China;Institute of Mechanics,Chinese Academy of Sciences,Beijing 100190,China)
出处
《钻采工艺》
CAS
北大核心
2021年第4期23-27,共5页
Drilling & Production Technology
关键词
流体力学
固井
当量循环密度
数值模拟
窄间隙
非牛顿流体
hydromechanics
cementing
equivalent circulating density
numerical simulation
narrow annuli
non-Newtonian fluid
