Abstract:

Based on the well structure size and the drilling parameters, the characteristic of drill pipe reverse rotation, the calculating formula of the reverse rotation speed and its bending frequency was analyzed in detail. The rotation speed is not only in the drill pipe, but also the reverse rotation speed is in the drill
pipe, its bending frequency is the sum of the drill pipe rotation speed and its reverse rotation speed. Under the certain drill pipe rotation speed, the reverse rotation speed of the drill pipe is related to the annulus gap ratio. The results indicated the measures prevented the drill pipe washout of Tarim oil field: 1. the rotation speed of the turntable should be controlled within 44.5-92.0 r/min; 2. Under the case of the certain drill pipe size, the casing size is increased to decrease the bending stress frequency; 3. The bottom hole dynamical drill tools were adopted. It provides the theoretical supports for the reasonable drill parameter selections of the deep well and extra-deep well.

Key words: drill pipe, reverse rotation motion, bending frequency, rotation speed, washout