Viscoelastic numerical modelling of wellbore stability in the salt formations

The rock salt viscous character can cause problems during whole life of well. Differential stresses at the wellbore wall can initiate the process of creep leading to high stresses which cause to reduction of wellbore radius and in higher rates and at longer time periods to severe damages like casing collapse and even wellbore abandonment. In this paper an analysis was conducted to evaluate the creep-induced wellbore convergence in salt formations, at X-oil field-one of oil fields at west of Iran- in which sever problems occurred at Asmari salt formation. A viscoelastic numerical analysis for rock salt creep behavior was performed by finite element method. The investigation results expectedly show an increase in the creep strain rate and decrease in well radius with time due to increasing differential stress. The results and especially decrease in well radius were in harmony with operational observations.

Keywords:

Salt , Creep , Viscoelastic , Finite element method , wellbore stability