Abstract: In conventional stratum, the casing strength is sufficient, and therefore the influence of casing eccentricity is generally less considered. However, in a deep well or in carbonate formations, the influence cannot be ignored. Considering eccentricity of casing in a circular hole, a finite element model is established and the effect of casing eccentricity on collapse resistance of casing analyzed. A contour map showing relationship between collapse resistance of casing and eccentricity is drawn, and a regression formula for eccentricity and the maximum casing stress is obtained. Simulation results show that, under non-uniform in-situ stress, the larger the casing eccentricity in hole, the greater the ability of casing resisting non-uniform loading in the maximum in-situ stress direction; and the larger the casing eccentricity in hole, the easier the casing damage becomes.

Key words: casing eccentricity, collapse resistance, failure of casing, formation, non-uniform in-situ stresses, regression formula