摘要
根据流体力学理论,以连续性方程和N-S方程为控制方程,利用计算流体力学理论对不同偏心度的赫巴流体环空流动进行系统的数值模拟,得到了偏心度的变化对于流场特性及摩阻压耗特性的影响规律,发现随偏心度不断增大,环空宽间隙处的流速剖面先不断增大,在达到临界最大流速剖面后又逐渐减小,其中先不断增大的规律依据已有研究且得到证实;运用涡黏理论对井壁、钻柱外壁及流体内部的应力-应变关系进行分析,揭示了达到临界流速剖面前、后流场内部不同的力学状态,以及随偏心度增大摩阻减小趋势不同的原因。最后回归出赫巴流体环空流动压耗随偏心度、流速及流体密度变化的理论预测模型。
According to hydromechanics theory, based on continuity equation and N-S equation, a systemat- ic numerical simulation is carried out on Herschel-Bulkely fluid flow with different eccentricities in annulus to iden- tify the impacts of variation of eccentricity on the flow field characteristic and friction pressure loss. It is found that, with eccentricity increasing, the velocity profile of wide gap in annulus increases gradually until the critical maxi- mum velocity profile is obtained, and then decreases. The increasing rule has been verified by existing researches. Moreover, eddy viscosity theory is applied to analyze the stress-strain relationship for well wall, drill string outer wall and fluid inside, to reveal different stress states inside fluid before and after the critical maximum velocity profile is obtained, and friction pressure loss variations with corresponding eccentricity. Finally, a friction pressure loss prediction model is regressed with eccentricity, velocity and fluid density as arguments.
出处
《石油机械》
2015年第9期19-23,共5页
China Petroleum Machinery
基金
国家科技重大专项"塔河油田深井尾管固井技术"(2011ZX05049-02-03)
关键词
偏心度
环空
赫巴流体
摩阻
流场特性
eccentricity
annulus
Herschel-Bulkley fluid
friction
flow field characteristic
