钻井离心机流场特性及重晶石回收效率分析

Analysis on Flow Field Characteristics and Barite Recovery Efficiency of Drilling Centrifuge

针对超深井高密度钻井液中重晶石的回收效率问题,将钻井液考虑为液-固-固流体模型,分析了离心机内流场的瞬态变化过程以及多种因素对重晶石和有害固相分布的影响,并对重晶石的回收效率进行了分析。分析结果表明:离心机沉渣池重晶石的体积分数远大于有害固相,轴向速度在离心机溢流口处达到最大;随着钻井液黏度的增大,沉渣池重晶石的回收效率明显降低,溢流口的重晶石体积分数呈现上升的趋势;随着转速和重晶石粒径的增大,沉渣池重晶石体积分数逐渐升高,溢流口返出的重晶石体积分数呈现下降趋势;粒径对重晶石的回收效率有很大影响。所得结论可以为钻井液中重晶石的回收与有害固相物的去除提供理论指导。

Aiming at the recovery efficiency of barite in high density drilling fluid of ultra-deep wells,the drilling fluid was considered as a liquid-solid-solid fluid model to analyze the transient change process of flow field in centrifuge and the influence of various factors on the distribution of barite and harmful solids,and analyze the recovery efficiency of barite.The analysis results show that the volume fraction of barite in centrifuge mud settler is much larger than that of harmful solids,and the axial velocity reaches the maximum at the overflow port of the centrifuge;as the viscosity increases,the recovery efficiency of barite in the mud settler decreases significantly,and the barite content at the overflow port shows an upward trend;as the rotary speed and the barite particle size increase,the barite content in the mud settler gradually increases,and the barite content returned from the overflow port shows a downward trend;and the particle size has great influence on the recovery efficiency of the barite.The conclusions provide theoretical guidance for the recovery of barite and the removal of harmful solids in drilling fluid.