幂律流体偏心环空螺旋流计算机仿真

偏心环空螺旋流是钻井作业常见的一种流动,怎样方便、快速及高精度地计算其流速场与流量是一个重要问题.根据1987年Luo和Peden提出的方法,利用数值计算高级语言MATHCAD结合现代计算机仿真计算技术,对幂律流体在偏心环空的螺旋流动做了研究,得到了这种流动的重要规律.从算例可以发现:在其它参数不变的情况下,钻柱的偏心对幂律流体螺旋流轴向流量的影响非常大.最大偏心时,轴向流量是同心时轴向流量的2.635倍,是最小偏心时轴向流量的1.668倍;钻柱的旋转速度对幂律流体螺旋流轴向流量的影响较小,但随钻柱旋转速度的增加,轴向流量有所增大,钻柱旋转速度最大时轴向流量是钻柱旋转速度最小时轴向流量的1.013倍.

Computer simulation of screw flow of power-law fluid in eccentric annulus

Screw flow in eccentric annulus is often encountered in drilling operation.How to calculate its flow velocity field and flow rate conveniently,quickly and exactly is an important aspect.According to the method put forward by Luo and Peden in 1987,screw flow of power-law fluid in eccentric annulus was studied and the flow rule was gained by using advanced numerical calculation language MATHCAD and modern computer simulation technique.It was observed from examples that eccentricity of drill string had major effect on the axial flow rate of Power-law screw fluid when the other parameters were invariant.The axial flow rate in the maximum eccentric annulus was 2.635 times that in concentric annulus,and 1.668 times that in the minimum-eccentric annulus;rotary velocity had a little effect on the axial flow rate,but the flow rate enhanced with the rotary velocity increase;the axial flow rate at maximum drilling string rotational speed is 1.013 times that at minimum drilling string rotary velocity.