基于钻井液流变性的涡轮钻具性能预测研究

Performance Prediction of Turbodrill Based on Rheology of Drilling Fluid

为探究钻井液流变性变化对涡轮钻具性能的影响,针对Ф89mm取心涡轮钻具涡轮级进行叶片建模,采用CFX进行不同钻井液性质下的多级涡轮仿真。流场及数值模拟结果表明:随着钻井液粘度增加,涡轮级的转矩呈对数增长、压降增大,效率降低,钻井液在涡轮级的出口速度减小;而钻井液密度的增加增大了其在涡轮定转子中的流速及压降,同时涡轮效率有所提高。研究结果可为优化涡轮叶片的设计提供依据;现场使用涡轮钻具,也应考虑其对钻井液流变性变化的适应能力,及时调整泵压、钻压保证最佳工况。

To explore the effect of the rheology of high-temperature deep-well drilling fluid on the performance of the turbodrill,the blade modeling for the turbine stage of 89 mm coring turbine was carried out,and the multi-stage turbine simulation under different drilling fluid properties was conducted by using CFX.The results of flow field and numerical simulation show that with the increase of the viscosity of drilling fluid,the torque,pressure drop and efficiency of turbine stage increased,and the velocity of drilling fluid at turbine stage decreased.The increase of drilling fluid density increases the velocity and pressure drop in the turbine rotor and increases the turbine efficiency.The results can provide basis for optimizing the design of turbine blades,and the adaptability of turbine drilling tools to rheological variation of drilling fluid should also be considered,the pump pressure should be adjusted in time,and the drilling pressure should be guaranteed under the optimum working conditions.