大位移水平井段岩屑运移实验研究

Experimental research on cuttings transport in extended-reach horizontal well

以相似系统理论建立了大位移水平井携岩实验装置,并根据颗粒雷诺数相似推导了实验装置与原型的参数相似关系,实验研究了环空返速、钻井液密度及有效黏度、岩屑密度及粒径大小、钻杆转速及偏心度、井斜角、机械钻速和井眼尺寸等10个参数与无因次岩屑床厚度的变化关系,在此基础上采用非线性回归方法建立了大位移水平井稳态无因次岩屑床厚度方程,并根据文献对模型进行了验证。模型对于确定大位移水平井井眼净化最小携岩排量和优化机械钻速具有参考意义。

Cuttings transport experiment device for extended-reach horizontal well was established based on the similarity system theory. The parameters similarity between the model and the prototype was deduced using the similar particle Reynolds number. Then, research was made on the variation of 10 parameters（i.e. annular velocity, mud density and effective viscosity, cuttings density and size, drillpipe rotation speed and eccentricity, inclination angle, rate of penetration and borehole size） with the dimensionless cutting-bed thickness. On this basis, a steady dimensionless cutting-bed thickness equation for extended-reach horizontal well was established with the nonlinear regression method, and the model was veriifed through literatures. The model provides a signiifcant guidance for borehole cleaning of minimum cuttings transport lfux and the optimization of ROP for extended-reach horizontal wells.