Development and application of an ultra short high energy turbodrill

Abstract:

In order to solve the problems of strong abrasiveness and slow ROP in drilling ultra deep formation, an ultra short high energy turbodrill was developed and field-tested. A multi curved 3D rotor blade was innovatively designed for the turbodrill. Based on the fluid dynamics software CFX, the spatial configuration layout of the rotor blade was optimized to increase the hydraulic energy conversion efficiency of the blade by 45%, and the torque by 43.55%. With integration of the power end with the thrust bearing, the split turbine mandrel was modified into a one-piece structure with the length of the rotor blade cut short to 8.3m from 15m of the imported one; thus greatly improving passage and safety of the turbodrill, and reducing reaming and gauging time. The torque and thread connection strength of the turbodrill were calibrated by the linear element simulation. The turbodrill has been successfully applied in 48 wells in quartz sandstone, igneous rock and gravel formation in Bozi and Yuanba blocks with an average increase of 100% in ROP, which provides a strong support for deep and ultra deep drilling in China.