气体钻井井底流场的三维数值模拟研究

3D Numerical Simulation of Bottom Hole Flow Field in Air Drilling

考虑空气锤钎头的排屑槽和硬质合金齿对气体钻井井底流场的影响,建立了气体钻井井底流场的数学模型和物理模型,对气体钻井井深3 000 m井底流场的速度场、压力场和温度场进行了数值模拟。结果表明:设计的空气锤钎头其井底流场的速度、压力和温度分布合理,流场可有效清洗井底、漫流携岩和冷却钎头牙齿,对称三喷嘴流道结构可用于空气锤钎头的研制。数值模拟结果与气体钻井经验公式的计算值比较吻合,结果可信,可用于指导空气锤钎头的结构优化设计和新产品的开发。

In order to solve the lifting capacity and cooling problem arising from gas drilling,CFD is used in air hammer bit＇s structural design.Considering the effects of junk slots and cutters on the flow field at bottom hole,the numerical model and physical model of the hole-bottom flow field of air hammer bit were established aimed at numerical simulation of flow field,pressure field and temperature field in the 3 000 m well depth.The study results indicate the patterns of flow field,pressure field and temperature field were reasonable with the designed air hammer bit.The flow field can clean and cool the TCI quickly;symmetric three-nozzle jets are effective to air hammer bit.The simulation results agree with the results calculated by empirical formula.It can be used to guide the design of air hammer bit and new product development.