Abstract:In drilling engineering,drill pipe often sticks in salt formation because of wellbore shrinkage. In the past,salt formation is often regarded as an elastic or elastic-plastic body,and the effect of time is not taken into account. However,engineering practice shows that the deformation of deep salt rock increases with time,that is,salt formation is of viscoelasticity. Supposing that salt formation is an isotropic and homogeneous viscoelastic body which obeys the Maxwell model,the wellbore shrinkage is studied carefully,and an expression for predicting wellbore shrinkage is proposed according to the elasticity-viscoelasticity correspondence principle. The expression will provide important reference to solving the problems of wellbore stability and the sticking of drill pipe in salt formation.