Intelligent pig inspection, evaluation and remediation of uncoated seamless pipelines

Conference · Thu Jul 01 04:00:00 EDT 1999

OSTI ID:20002582

Shamblin, T R

Many gas pipelines in operation in the US today were constructed prior to coating and cathodic protection (CP) current practices. A number of these vintage pipelines had no coating and had CP installed long after their construction thus allowing initial corrosion growths. With continual public and industrial growth and development on and around these pipelines, plus normal maintenance, there is a need to conduct periodic integrity assessments to insure public safety and maintain pipeline efficiency. One of the best tools currently available to measure or gauge pipeline integrity is the intelligent or smart pig. While there are various technologies offered by In-line inspection (ILI) vendors, magnetic flux leakage (MFL) is the one most commonly utilized for in-line inspections of natural gas pipelines. Over the years there has been much speculation over the ability of an MFL tool to clearly define corrosion magnitudes on uncoated pipelines because the MFL signals are distorted by the external corrosion crust or growth. In addition, many of the uncoated lines constructed utilized seamless pipe which compounds the problem with uneven wall thickness common with seamless pipe. Also, the irregular internal surfaces produce additional distortions or noise in the MFL signal. Analysis of the smart pig results are quite difficult when evaluating an uncoated seamless pipeline. However, with the latest advances in MFL smart pigs it is possible to accurately analyze corrosion on uncoated seamless steel pipelines. The ability to accurately identify corrosion on such structures provides the mechanism to evaluate the pipeline's integrity with analytical tools such as RSTRENG, (remaining strength). From that a successful remediation program can be developed which will save the pipeline operator millions of dollars when compared to the expensive alternative of replacing the pipeline.

• Research Organization: Columbia Gas Transmission, Charleston, WV (US)
• OSTI ID: 20002582
• Report Number(s): CONF-990401--
• Country of Publication: United States
• Language: English

Related Subjects

03 NATURAL GAS
36 MATERIALS SCIENCE
CARBON STEELS
CORROSION
IN-SERVICE INSPECTION
MAGNETIC TESTING
MAINTENANCE FACILITIES
NATURAL GAS
PIPELINES
RELIABILITY
REPAIR