Coiled-Tubing Failure Statistics Used To Develop CT Performance Indicators

Abstract

Summary Coiled-tubing (CT) failures have not disappeared with a greater understanding of low-cycle fatigue in the industry. A comprehensive process to systematically analyze CT field failures has been in place since 1995. This paper describes the systematic failure-analysis process and the resulting CT failure database, which now includes more than 360 CT failures. The information reported here covers from 1995 to 2001 during a major service company's global CT operations. The failure analysis delivers two types of statistics—the mode of failure during the event (failure mechanism) and the cause that led to it (failure cause). The failure trends for both mechanism and cause are discussed. The CT volume used during these operations, in combination with the accumulated failures, allows for the introduction and discussion of CT performance indicators (CTPIs) that can be considered representative for the industry.