MATTHEW BROWN, MICHAEL R. BLOOD and STEFANIE DAZIO / Associated Press
Investigators investigating the cause of an undersea oil pipeline demolition off the coast of Southern California have drawn attention to the possibility that a ship’s anchor pulled and cracked the line across the ocean floor, but two videos released so far offer tantalizing clues as to what is happening could be under the sea surface.
A Coast Guard video released Thursday appears to show a trench in the ocean floor causing the underwater line to bend, but experts have given mixed opinions about the meaning of the short, grainy shots. A previous video showed a thin, 13-inch-long crack in the pipe. The pipe showed no signs of damage that experts said would be expected from cargo ships routinely cruising the area outside the ports of Los Angeles and Long Beach in the event of a collision with a ton-heavy anchor.
The slight curvature in the line shown in a video “doesn’t necessarily look like anchor damage,” said Frank G. Adams, president of Interface Consulting International, based in Houston, in an email. When a pipeline is hit by an anchor or other heavy object, “it usually results in physical damage that can lead to rupture”.
Ramanan Krishnamoorti, a petroleum engineering professor at the University of Houston, said he found the video, which runs along a curve in the line, “revealing.”
“It seems to me that you dragged something in the sand that may have affected the pipeline,” he said. He remained confused, however, that the leak was from a tear rather than a major cut, assuming it was hit by an anchor or other object.
Reports of a possible Huntington Beach spill were first released on Friday night, but the leak wasn’t discovered until Saturday morning. While the size of the spill is unknown, the Coast Guard on Thursday slightly revised the parameters of the estimates to at least about 25,000 gallons and no more than 132,000 gallons.
The Coast Guard said about 5,500 gallons of crude oil were recovered from the sea. The oil has spread southeast along the coast, with reports of small amounts coming ashore in San Diego County, approximately 50 miles from the original location.
So far, the impact on forest fires has been minimal – 10 dead birds and another 25 recovered and treated alive – but environmentalists warn that the long-term effects could be much greater. While shore cleanups continued, some beaches in Laguna Beach reopened on Friday, although the public is still unable to get into the water.
Key questions remain: Could the line have been hit days before the leak began? Which ship is responsible? And if a ship’s anchor isn’t to blame, what else could it be? Investigators, meanwhile, continued to look for the cause of the break and determined what happened in the crucial early hours of the morning after reports of a possible oil spill were first received.
The tight cut seen in a video could explain why there were signs of an oil spill on Friday night but the pipeline operator was undetected for more than 12 hours.
“My experience suggests this would be a darned difficult leak that can be quickly detected remotely,” said Richard Kuprewicz, a private pipeline accident investigator and consultant. “An opening of this kind on a 27-kilometer long underwater pipe is very difficult to detect using remote displays. These crack-type releases are lower and can take a long time. “
When pipes suffer a catastrophic failure, the break is usually much larger, what is known in the industry as a “fish mouth” because it gapes wide like a fish mouth, he said.
Amplify Energy, a Houston-based company that owns and operates three offshore oil rigs and the pipeline south of Los Angeles, said it didn’t know there was a leak until its workers did one at 8:09 a.m. on Saturday I discovered the sheen of oil on the water
The Coast Guard said Thursday that it is investigating the incident with other authorities as a “major marine casualty” due to the possible involvement of a ship and more than $ 500,000 in damage. It said they will decide whether criminal charges, civil penalties, or new laws or regulations are needed.
The leak occurred about 5 miles offshore at a depth of about 98 feet, according to investigators. A 4,000-foot section of the pipeline was removed 105 feet and bent back like a string on an arch, said Martyn Willsher, CEO of Amplify.
Jonathan Stewart, professor of civil and environmental engineering at the University of California, Los Angeles, said he was surprised that the damage wasn’t more serious, given the removal of the pipe.
“My first reaction, when I heard it had been repressed so far, was that it was remarkable that it was intact at all,” said Stewart.
Moving a large section of pipe up to 105 feet would have created “bending deformations” – tension on one side stretched into a semicircle with compression on the other as it bent inward, Stewart said.
It’s possible that such pressure on its own could cause an interruption, despite Stewart saying that there is too little information to draw a conclusion about the cause. It is possible that a sharp section of the anchor pierced the pipeline, but “you could still have damage from bending alone”.
“As it pulls on the pipe, you create these bending stresses in the pipe that can eventually get so great that they break it,” he said.
Questions remain as to when the oil company knew it had a problem and delays in reporting the oil spill.
A foreign ship anchored in the waters off Huntington Beach reported to the Coast Guard that it saw more than 2 miles of shine just after 6 p.m. on October 1, and that evening a satellite image from the European Space Agency also indicated ( ESA) pointed to a likely oil spill reported to the Coast Guard at 2:06 a.m. on Saturday after being reviewed by an analyst with the National Oceanic and Atmospheric Administration.
Federal pipeline safety officials have set the incident for 2:30 a.m. on Saturday, but say the company didn’t close the pipeline until 6:01 a.m. – more than three hours after a negative pressure alarm was raised indicating a potential problem – and only reported the leak to the Coast Guard at 9:07 a.m. Federal and state regulations require immediate notification of a spill.
Amplify said the line was shut down as early as 6 a.m., then restarted for five minutes for a “meter reading” and then shut down again. A counter reading shows how much oil is flowing into and out of the line. The company could have used this information to confirm whether the pressure change alarm was triggered because the line was leaking, Krishnamoorti and Kuprewicz said.
The company said a boat discovered oil on the water at 8:09 a.m.
Willsher, who spent four days asking questions with the Coast Guard and other officials, did not appear at the press conference on Thursday. Other officials refused to explain his absence.
Brian Melley contributed from Los Angeles.