Coiled tubing (CT) and coiled tubing units (CTU) technology has been widely used in oil and gas field since World War II. Coiled tubing fatigue failure is one of the constraints on promoting used. CT bears complex loads, leading to multiple plastic deformations when operating. Then the fatigue damage cannot be ignored. Through the mechanics analysis of CT with finite element method (FEM) in working state at the wellhead, the results show that high stress and high strain are the main factors which cause CT failure. Based on the analysis, the fatigue life is predicted for CT without defects by using Manson-Coffin formula. The results of CT with different inner pressure show that simulations result is closer to the actual working conditions.
The purpose of this paper is to discuss the plastic deformation and pressure reversal of pipe during hydrostatic testing. The higher the test pressure, the smaller the number of defects that remain undetected. In order to study the effect of hydrostatic testing, full scale burst experiments were carried out with API 5L X65 SSAW pipes of 660mm outside diameter and 12.5 mm wall thickness. Nine spiral oriented deflects had been machined in the weld. Deformations of deflects were measured. The pressure reversal was computed. It can be concluded that if a hydrostatic test can be successfully accomplished without the failure of any defect, the likelihood of a pressure reversal will be extremely small.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
customersupport@researchsolutions.com
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.