论文部分内容阅读
建立了偏心度在井眼内按线性及正弦规律变化的偏心环空流问题理论模型。提出了关于变偏心度环空中计算非牛顿流体在层流、过渡流及紊流状态下压降、流速的方法；给出了流场特性分析及数值模拟结果。研究表明：对于偏心度沿轴向变化率大、流态处于过渡流情况，压力梯度比同心环空高。在变偏心度环空中，流体呈二维流动；沿井眼轴线方向上，ｕ，ｖ具有多变性；在环空宽间隙处，流体质点将减速运动，而在环空窄间隙处，流体质点将加速；质点轨迹呈Ｓ型。
The theoretical model of eccentric annulus flow with eccentricity changing linearly and sinusoidally in wellbore is established. A new method to calculate the pressure drop and flow velocity of non-Newtonian fluid in laminar flow, transient flow and turbulent flow environment is presented. The flow field characteristics and numerical simulation results are given. The results show that the pressure gradient is higher than that of concentric annulus for the large change rate of eccentricity in the axial direction and the flow regime in the transitional flow. In the annulus of variable eccentricity, the fluid flows in two dimensions; in the direction of the borehole axis, u and v have variability; at wide annuli of the annulus, the fluid particles will decelerate, whereas in the narrow annular space, the fluid particles Will accelerate; particle trajectory was S-shaped.