The failure probability of wellbore is high in HPHT gas wells because of the effect of the hole angle, the cementing complications and the high pressure high temperature environment. However, most of the researches about the cement problems are studied by two dimensional modeling. The effect of hole angle and cement complications on HPHT well integrity in three dimension is hardly studied.

In the analysis, the finite element method was used to build a three dimension simulation model where the hole angle, casing eccentricity, and cement channels are considered. One cement system (118-lbm/ft3) commonly applied in oil field is used to study the effect of cement complications on the wellbore integrity. The hole angle, cement channel angle, and casing eccentricity are the variables taken into account and an attempt is made to which parameter is the most important and its effects on wellbore failure.

In the cement channeling, the casing has highest von Mises stress at the hole angle of 90°, and the cement tends to fail in tension. The casing eccentricity tends to reduce cement shear stress, and tensile stress but increase cement compressive stress. The cement has the highest compressive failure probability in casing eccentricity condition. At the casing eccentricity lower than 40%, for different hole angle, the casing eccentricity has minor effect on the casing.

This paper presents the sensitivities of the variables and gives a better understanding of the effect of hole angle and cement complications on the HPHT well integrity.

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