Abstract:

Aiming at safe and high effective borehole enlargement issue of deep well，ultradeep well and high pressure oil/gas well in drilling operation，actual force

behaviors of drilling string assembly reaming while drilling in downhole are researched，by using triaxial finite element approach twisting vibration of reaming drill

string while drilling is simulated.A mechanics analytic model of twisting vibration effect is proposed by researching the factors such as mass bias of hole opener，top

backup of drilling rig etc，and mechanics issues，such as frequency of twisting vibration and strength of kinetics，etc，of drilling string assembly reaming while drilling

are discussed.By means of the analysis，the technique measurement to decrease hazard of twisting vibration in actual drilling operation is proposed.The measurement provides

a set of theoretical basic and reference criteria for safely drilling deep oil/gas well and optimal drilling parameters of high efficiency reaming while drilling.

Key words: deep oil/gas well, drilling, reaming while drilling, twisting vibration