Collapse strength analysis of casing design using finite element method

Accurately predicting the ultimate collapse strength is very important in t he design of casings for the oil and gas industry. For an infinitely long t hick walled casing subjected to external pressure, a finite element model h as been proposed to achieve a better understanding of the ultimate collapse strength of casing. Careful comparison with a series of full-scale experim ents has been conducted to verify the accuracy and reliability of the finit e element model. In addition, several current predictive equations for casi ng design have been assessed using those available test data. The validatio n proves that, if the material behaviour and imperfection variables are kno wn, the ultimate collapse strength of casing can be predicted to a satisfac tory degree of accuracy. Major factors, which affect the collapse strength of casing, were studied and their effects on the collapse strength of casin g were summarized. Regression analysis has been conducted on the basis of f inite element predictions and a new design equation for casing collapse is presented. (C) 2000 Elsevier Science Ltd. All rights reserved.