The influence of double pitting corrosion on casing collapsing strength based on different ellipsoid shape

Abstract

Abstract. Acidic environment always contributes on casing corrosion phenomenon, the local corrosion and pitting lead to stress concentration, which decreases the strength and is an important factor to cause damage to the casing. The influences of distance of two pitting, corrosion depth, section parameter on collapsing strength of casing are quantitatively analyzed under the condition of double pitting axial distribution and ring distribution. The results showed that the maximum Von Mises stress of casing first increases, and then goes down to a steady state as the distance of double pitting grows under the condition of double pitting axial distribution, while the stress goes down to a steady state as the distance of double pitting grows under the condition of double pitting ring distribution. It can provide the theoretical foundation for the casing design through analyzing and comparing the influence of double pitting on the collapsing strength of casing under different condition.