vibration drilling[vī′brā·shən ′dril·iŋ]
a technique involving the use of a vibrator to induce oscillations of the drilling tool. Vibration drilling is carried out at depths of 20-30 m in soft rock without rotation of the tool (the vibrator is attached to the upper end of the drill pipes); vibration drilling in hard rock and at depths greater than 30 m uses simultaneous rotation of the tool (the vibrator is installed directly above the drilling tool, or bit). In the first case, direct-acting electromechanical vibrators are most often used; in the second case, hydraulic (direct-acting, reciprocating, or double-acting) vibrators driven by the stream of flushing liquid. Shock absorbers mounted above the vibrator are used to protect the drill pipes from the harmful effects of vibrations during deep drilling.
Vibration drilling of shallow holes offers an increase in productivity by a factor of 1.5 to 2 compared to percussion-rotary drilling; vibration drilling of deep holes, particularly in hard rock, increases bit life without any adverse effect on the other performance indexes. The main problem with regard to the further development of vibration drilling is the construction of reliable vibrators. Vibration drilling is used in geological surveys, in the construction of deep-set supports, and in drilling for oil and gas. The method was invented and developed in the USSR (1948).
REFERENCESBarkan, D. D. Vibrometod v stroitel’stve. Moscow, 1959.
Vibratsionnoe i udarno-vrashchatel’noe burenie. Moscow, 1961.
Rebrik, B. M. Vibrotekhnika v burenii, 2nd ed. Moscow, 1966.
D. D. BARKAN