NACE Interview: Integrity Management Solutions For Offshore Pipeline Corrosion

March 2011, Vol. 238 No. 3

Binder Singh

Corrosion of offshore oil and gas pipelines is a critical problem that can lead to catastrophic failure if not properly managed—from the design stage of the pipeline system through ongoing monitoring and maintenance.

Corrosion understanding and mitigation methods have greatly improved over time, but significant challenges remain in the difficult subsea environment, where assets can be located up to a mile deep or more.

The issue looms large on the radar scope of NACE International, The Corrosion Society, which has more than 25,000 members around the world involved in research and implementation of corrosion control methods such as protective coatings, inhibitors, cathodic protection (CP) and materials selection and design.

Says NACE Executive Director Bob Chalker, “NACE members are charged with protecting infrastructure and assets in every industry and in all types of environments and conditions while complying with strict regulatory requirements.

“Offshore pipelines pose particular challenges, not only from the harsh saltwater environment, but because they are difficult to access, especially as oil and gas companies explore, produce, and transport products from deeper and deeper water.”

NACE will present the forum, “Future Challenges of Deepwater Offshore Corrosion and Integrity Management,” at its annual conference, CORROSION 2011, to be held March 13-17 in Houston.

Chalker invited forum presenter Binder Singh—a 16-year NACE member with 28 years of nuclear, marine, and offshore corrosion experience—to answer a series of questions about subsea pipeline corrosion in particular and the latest solutions to control it.

Chalker: How serious of a problem is corrosion on offshore oil and gas pipelines?

Singh: Very serious. Many international surveys have revealed that offshore pipeline failures are attributed to internal corrosion more than 50% of the time. External corrosion is still an issue but is generally quite well addressed using good CP and coatings. The issues are more important and critical for deepwater pipelines whereupon designs are more complex; and inspection, monitoring, and repair are very difficult and costly.

Integrity management has tended to be regarded predominantly as a corrosion management exercise. This is now even more emphasized when dealing with deepwater conditions. The problems of corrosion and integrity management are compounded by the fact that project management is very heavily governed by costs and schedule. This is accepted as a fact of life but the odds are now moving more in favor of safety, reliability, and conservatism in both design and operations.

Chalker: What is it about the offshore environment that causes these assets to corrode?

Singh: Generally offshore environments and subsea reservoirs tend to be more corrosive than their onshore counterparts. On land, designers often get a chance to see the results of their work more readily; in contrast, the feedback cycle is more rare offshore and subsea, and thus a greater time lag exists between design, construction, and operations. Therefore, the dissemination of new information and/or knowledge is imparted more slowly. The situation is improving, however, as the offshore industry grows in stature and maturity. But materials and corrosion engineers should still be encouraged to follow up on the performance of their design and consulting decisions once executed.