FIELD TEST OF JWZ250 DECELERATING TURBODRILL IN WELL QIUDONG-10

The penetration rate of large hole drilling can be highly increased by the decelerating turbo-drill with medium rotary speed,low pressure drop and large torque,combined with high quality and efficiency PDC bits or ATM and MAX roller bits.This paper presents the working principle,features of 250mm decelerating turbodrill and its field testing in Well Qiudong-10 of Tuba Oilfield.The field test indicates that the penetration rates of the decelerating turbodrill is increased by 230% with roller bits,and by 336% with PDC bits.The drilling cycle is shorten and the drilling cost is reduced by the use of turbodrill.