【摘要】 在石油钻采工程中,井筒内流体多为非牛顿流体,在旋转杆管柱作用下做偏心环空螺旋流,而且偏心度沿杆管柱轴线呈任意变化。针对这一流体特性,建立了轴向变截面偏心环空幂律流体三维有限元模型,采用基于有限元的有限体积法,研究了流场分布规律及偏心度和转速对界面力的影响。计算结果表明:宽间隙侧最大轴向速度不变,旋转速度降低,窄间隙侧最大轴向速度降低,旋转速度增强。随着转速或偏心度的增加,流体对杆管柱作用的横向力和弯矩均增大,为进一步揭示和防治杆管偏磨提供了理论依据。更多还原

【Abstract】 In oil drilling and production engineering,fluid in well bore are mostly non-Newtonian fluid,their flow pattern is eccentric annulus helical flow as the result of the effect of string rotation,the eccentricity change along the axial line of string arbitrarily.In view of this character,3D finite element model of axial variable cross-section eccentric annulus power law fluid is established.Adopting the finite volume method basing on finite element,the effect of flow field distribution rule,the eccentricity and the rotation velocity on boundary force are researched.The results demonstrate that the axial velocity with wide interspace is unchangeable and the rotation velocity is decreased,while the axial velocity with narrow interspace is decreased and the rotation velocity is increased.As the increase of the rotation velocity and the eccentricity,it increases to the cross force and the bending moment which bear on the string,it further provides the theoretical basis for the revealing and preventing the string from wear.更多还原