基于CFD模拟的文丘里打捞篮喷嘴结构参数优化

Optimization of Nozzle Structural Parameters of a Venturi-Based Fishing Basket Based on CFD Simulation

摘要: 针对油气开采过程中井筒内碎屑沉积导致清理困难及施工效率降低等问题，基于文丘里原理设计了一种井下碎屑打捞篮装置。利用计算流体力学(CFD)方法，对打捞篮内部流场进行了数值模拟分析，研究了喷嘴角度、喷嘴入口段长度及喷嘴出口段长度对负压区域形成及碎屑循环吸附效果的影响规律。结果表明，喷嘴结构参数对回收篮内部速度分布及负压区域形成有显著影响。当喷嘴角度为40˚时，装置对井筒内壁冲刷作用较强冲刷范围最广，同时可在井筒内形成稳定且范围较大的负压区。当喷嘴入口段长度为11 mm时，射流发展充分，流场结构稳定，有利于增强碎屑卷吸能力。当喷嘴出口段长度为11 mm时，喷嘴出口处压力差最大，负压分布均匀，吸附效果最佳。综合分析可知，在喷嘴角度40˚、入口段长度11 mm及出口段长度11 mm的参数组合下，文丘里打捞篮能够实现射流冲刷与负压吸附的强化，其碎屑清理与回收性能最优。

Abstract: During oil and gas production, debris deposition in the wellbore often leads to cleaning difficulties and reduced operational efficiency. To address this issue, a downhole debris recovery basket based on the Venturi principle was designed. Computational fluid dynamics (CFD) was employed to numerically simulate and analyze the internal flow field of the recovery basket, with particular focus on the effects of nozzle angle, nozzle inlet length, and nozzle outlet length on the formation of negative-pressure regions and the circulation and entrainment of debris. The results show that the nozzle structural parameters have a significant influence on the velocity distribution inside the recovery basket and the formation of negative-pressure zones. When the nozzle angle is 40˚, the device exhibits stronger scouring action on the wellbore wall and the widest scouring range, while also generating a stable and relatively large negative-pressure region within the wellbore. When the nozzle inlet length is 11 mm, the jet develops more fully and the flow field remains more stable, which is beneficial for enhancing debris entrainment. When the nozzle outlet length is 11 mm, the pressure difference at the nozzle outlet reaches its maximum, the negative-pressure distribution becomes more uniform, and the suction effect is optimal. Comprehensive analysis indicates that, under the combined parameters of a nozzle angle of 40˚, an inlet length of 11 mm, and an outlet length of 11 mm, the Venturi recovery basket achieves enhanced jet scouring and negative-pressure suction, resulting in optimal debris cleaning and recovery performance.