液控随钻扩眼器球座冲蚀规律及结构优化

Erosion Rule and Structure Optimization of Ball Seat of Hydraulically Controlled Reamer While Drilling

在随钻扩眼的过程中,扩眼器球座的冲蚀较为严重,尤其是球座旁通孔附近。基于冲蚀理论与固液两相流理论,结合DPM离散相模型对扩眼器球座进行冲蚀模拟分析,研究不同因素对扩眼器球座冲蚀的影响规律。此外,利用正交试验方法,研究各参数对冲蚀磨损的影响程度,并优化扩眼器球座结构。通过极差和方差分析可知:影响球座冲蚀磨损的因素依次为流量>含砂比>颗粒直径,最优工艺参数组合为:流量35 L/s、含砂比3%、黏度0.028 Pa·s、颗粒直径0.25 mm、颗粒密度1 500 kg/m~3,此时球座的冲蚀率最小,为4.52×10^(-6) kg/(m~2·s)。为了减少扩眼器球座的冲蚀,对球座进行结构优化,优化后球座旁通孔角度为顺时针倾斜45°、圆角半径为7 mm、个数为6,相比优化前的球座冲蚀率降低了24%。

In the process of reaming while drilling,the erosion of the reamer ball seat is serious,especially near the bypass hole of ball seat.Based on erosion and solid-liquid two-phase flow theory,erosion simulation analysis were carried out combining DPM discrete phase model,and the influence of different factors on reamer ball seat erosion was studied.In addition,the orthogonal test method was used to study the influence degree of each parameter on erosion wear and optimize the structure of reamer ball seat.According to the analysis of range and variance,the factors affecting the erosion wear of the ball seat are flow>sand content ratio>particle diameter.The optimal process parameter combination is:flow is 35 L/s,sand ratio is 3%,viscosity is 0.028 Pa·s,particle diameter is 0.25 mm and particle density is 1 500 kg/m~3,the erosion rate of the ball seat is the minimum,which is 4.52×10~(-6)kg/(m~2·s).In order to reduce the erosion of reamer ball seat,the structure of the ball seat was optimized.After optimization,the bypass hole angle of the ball seat is 45° clockwise,the fillet radius is 7 mm,and the number is 6,the erosion rate of the ball seat reduces by 24% compared with that before optimization.