Application of Titanium Alloy Tubing in HPHT Gas Wells to Reduce Vibration and Buckling

Abstract

Tubing string vibration and buckling are primary causes of tubing string failure, sustained casing pressure and production casing wear in HPHT gas wells. In order to obtain an improved understanding of tubing string vibration and buckling, finite element analysis is carried out in this paper. Typical tubing string failures in HPHT gas wells are analyzed, and fracture surfaces are tested. The vibration and buckling characteristics of original nickel-base alloy tubing string and modified tubing string with Titanium alloy tubing are calculated and compared. The results indicate that the application of Titanium alloy tubing can effectively reduce tubing string vibration and buckling. Titanium alloy tubing has lower elasticity modulus, so it transforms more energy into deformation energy rather displacement energy. Therefore, it is concluded that Titanium alloy tubing can effectively reduce tubing axial vibration displacement, so as to prevent tubing fatigue and thread looseness. Original tubing string has contacted with the wellbore under sinusoidal buckling. The sinusoidal buckling of modified tubing string is much slighter and tubing doesn’t contact with the wellbore. The work presented in this paper can provide a technological basis for the reduction of tubing string vibration and buckling, as well as application of Titanium alloy tubing.