A year after the Mayflower oil spill, ExxonMobil executives are submitting a pipeline remediation plan to federal regulators that will include extraordinary integrity testing measures that may take more than a year to complete.
The oil and gas giant has also discovered additional factors that may have caused the pipeline to rupture.
In an exclusive interview with Talk Business & Politics, vice-president for U.S. Pipeline Operations Karen Tyrone said the Pegasus pipeline will be put through a “spike hydrostatic test,” which will push water through the conduit at 1.39 times the maximum operating pressure to stress the pipe beyond any weak points.
“The purpose of a spike hydrotest is to reveal and eliminate any of these weak, original manufacturing defects that could ultimately be an integrity problem for you,” Tyrone said. “It will be testing the pipeline beyond what it’s ever been tested before.”
Tyrone also said the Mayflower incident has fundamentally changed her industry’s approach to pipeline management due to the unprecedented nature of factors that caused the pipeline to burst on March 29, 2013.
“We [Exxon Mobil] have not seen anything like this and [our] industry has not seen anything like this,” she said, in explaining why the investigative process has taken so long. “We took months to analyze the data. We wanted to make sure we understood what happened. Part of that analysis was eliminating other potential contributing factors.”
TESTING FOR FAILURE
Last July, investigators determined that the 60-year old Pegasus pipeline ruptured due to manufacturing defects from the maker. Tyrone said additional studies have shown that chemicals found in the pipe are different than any pipeline rupture the company or the oil and gas industry have previously experienced.
“We’ve confirmed that the factors that resulted in the failure of the pipeline in Mayflower, Arkansas are an original manufacturing defect that was created when the seam pipe was manufactured combined with extreme metallurgical properties,” Tyrone said.
She explained that the metallurgical property test results on the burst pipeline showed the “chemical make-up of that joint was different than we have ever seen.” Tyrone said the pipeline had higher quantities of sulfur, manganese, and carbon than should exist and that the combination of chemical levels had stumped experts from around the world.
Tyrone said records on the manufacturing process for the pipe from the 1940’s don’t exist, so scientists are left to speculate that the manufacturing process was compromised decades ago.
She also said that additional testing on nearby sections of the pipeline have not shown the compromise that the 22-ft. ruptured section exhibited.
Tyrone said the remediation plan that will be submitted to the Pipeline and Hazardous Materials Safety Administration (PHMSA) will include “multiple layers of integrity” testing. Besides the spike hydrostatic test, Exxon Mobil will re-examine the data from the inline inspection that occurred before the break and address “anomalies.”
She said this process would include digging up sections of the pipeline for additional testing, if necessary. The remediation plan will also test other areas of the pipeline for the metallurgical inconsistencies found in the ruptured section.
“We anticipate it will take a minimum of a year,” Tyrone said.
THE FUTURE OF PEGASUS
When asked if the company needs the pipeline if it is offline for more than two years, Tyrone said yes.
“We think the pipeline is a very valuable asset,” she said, emphasizing that pipeline transportation remains safer for moving crude oil than other options such as truck, train or barge. “Yes, we anticipate a use for the pipeline and a need for the pipeline.”
Tyrone also indicated that moving the pipeline out of the Lake Maumelle watershed seemed doubtful.
“I would hate to speculate on next steps.. When we execute that remedial work plan, we will repair, reinforce, or replace the pipe as necessary to ensure the integrity of the pipe,” she said. “We won’t restart the pipeline without PHMSA approval and without convincing ourselves that we can safely do that.”
Below you can watch the full interview with Karen Tyrone, who appeared on this week’s edition of Talk Business & Politics, which airs Sundays at 9 a.m. on KATV Ch. 7.