PIPELINE INTEGRITY ANALYSIS BASED ON INTERDISCIPLINARY COOPERATION

For many years, BP Pipelines, North America has used high-resolution Magnetic Flux Leakage (MFL) in-line inspection (ILI) technology to help maintain the integrity of their pipelines. The improvements in this technology that now allow an Operator to make integrity decisions also bring challenges. Reports from ILI can list thousands, or even hundreds of thousands, of individual anomalies or features. When combined with data from NDT field measurements and existing pipe tallies, it can become overwhelming. Methods had to be developed to distill this information for further analysis. BP Pipelines NA encouraged cooperation between all parties involved in the integrity process to adapt reporting requirements and work procedures to provide the best available information for integrity analysis and to ensure continued improvements. This cooperation is a key part of the integrity equation and essential to a successful program. This paper presents an overview of the validation process undertaken on a 51 km (32-mile) section of 457 mm (18-inch) pipeline. This pipe section was inspected in 1999 and again in 2003 by the same inspection company. This provided an opportunity to evaluate improvements in inspection technology, assess repeatability of performance and develop an engineering based approach to review, analyze, and validate high-resolution metal loss MFL data. Field verification and data validation included the use of a several NDE techniques to acquire field measurements to overlay and compare to the ILI inspection data. Anomaly classification and distribution is examined and methods of selecting validation locations for future inspection developed. In addition to the primary goal outlined, the 2003 repair program provided an opportunity to evaluate the performance of the composite sleeve reinforcements applied in 1999, after 4 years of service.Copyright © 2004 by ASME