HUNTINGTON BEACH, Calif. (AP) – Investigators looking for the cause of a ruptured submarine pipeline off the southern California coast have highlighted the possibility that a ship anchor dragged the line on the seabed and cracked it, but two videos have been posted so far that only provide tantalizing clues as to what might have happened beneath the ocean’s surface.
A Coast Guard video released Thursday appears to show a trench in the seabed leading to a bend in the submerged line, but experts have offered varying opinions on the meaning of the short, grainy shots. An earlier video revealed a thin 13-inch-long break in the line. The pipe showed no evidence of damage that experts said would be expected from a collision with a multi-ton anchor from freighters that regularly move in the area off the ports of Los Angeles and Long Beach.
The slight arc in the line shown in a video “Does not necessarily look like anchor damage”, Frank G. Adams, president of Houston-based Interface Consulting International, said in an email. When a pipeline is struck by an anchor or other heavy object “Which usually results in physical damage that can lead to a fracture.”
Ramanan Krishnamoorti, professor of petroleum engineering at the University of Houston, said he viewed the video running along a bend in the line “developer.”
“It looks to me like you have something that was dragged through the sand that could have impacted the pipeline”, he said. However, he remained puzzled that the leak was from a crack and not a larger gash, assuming it was hit by an anchor or other object.
Reports of a possible spill off Huntington Beach were first published on Friday evening, but the leak was not discovered until Saturday morning. Although the size of the spill is not known, the Coast Guard revised the parameters slightly on Thursday from estimates to at least about 25,000 gallons (95,000 liters) and no more than 132,000 gallons (500,000 liters).
The Coast Guard said about 5,500 gallons (20,819 liters) of crude was recovered from the ocean. The oil spread southeast along the coast with reports of small amounts landing in San Diego County, about 50 miles from the original site.
So far, the impact on the wildfires has been minimal – 10 birds dead and 25 others recovered alive and treated – but conservationists warn that the long-term impacts could be much greater. As the cleanup continued on the shore, some beaches in Laguna Beach reopened on Friday, although the public still couldn’t get in the water.
Key questions remain: Could the line have been hit several days before the start of the leak? Which vessel is responsible? And if a ship’s anchor isn’t the culprit, what else could it be? Investigators, meanwhile, continued to investigate the cause of the rupture, as well as to determine what happened in the crucial first hours after the first reports of a possible oil spill.
The narrow gash seen in a video could explain why signs of an oil slick were seen on Friday evening, but the spill escaped detection by the pipeline operator for more than 12 hours.
“My experience suggests that this would be a damn difficult leak to determine quickly from a distance,” said Richard Kuprewicz, a private investigator and consultant on pipeline accidents. “An opening like this, on a 17-mile-long underwater pipe, is very difficult to spot by indications from a distance. These crack-like releases are weaker and can last for some time. “
When pipes fail catastrophically, the breach is usually much larger, which is referred to in the industry as a “fish mouth” breaking because it’s as big as a fish’s mouth, he says.
Amplify Energy, a Houston-based company that owns and operates three offshore oil rigs and the pipeline south of Los Angeles, said it did not know there had been a spill until its employees detect an oil burst on the water at 8:09 a.m. on Saturday. a m
The Coast Guard said Thursday it was investigating the incident with other agencies as “Major sea accident” due to the potential involvement of a vessel and damage exceeding $ 500,000. He said they will determine 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, investigators said. A 4,000-foot section of the pipeline was dislodged 105 feet, bent like a bowstring, Amplify CEO Martyn Willsher said.
Jonathan Stewart, professor of civil and environmental engineering at the University of California, Los Angeles, said he was surprised the damage wasn’t more severe given the distance the pipe was moved.
“My first reaction when I heard that it was out of place so far is that it is remarkable that it is even intact at all”, said Stewart.
Moving a large section of pipe up to 105 feet (32 meters) would have caused “bending deformations” – tension on the side that was stretched in a semicircle, with compression on the other, as it was bent inward, Stewart said.
It’s possible that such pressure alone could lead to a rupture, although Stewart said there was too little information to draw a conclusion about the cause. It is possible that a sharp anchor section could pierce the pipeline, but “You could still have damage just from the bending.”
“Because it pulls on the pipe, you create these bending stresses in the pipe, which could eventually become large enough to break it.” he said.
Questions remain as to when the oil company knew it had a problem and delays in reporting the spill.
A foreign vessel anchored in the waters off Huntington Beach reported to the Coast Guard that it saw a burst of more than 2 miles just after 6 p.m. on October 1 and that evening, an Agency satellite image Space also indicated a probable oil slick, which was reported to the Coast Guard at 2:06 a.m. Saturday, after being examined by an analyst with the National Oceanic and Atmospheric Administration.
Federal pipeline safety regulators set the time of the incident at 2:30 a.m. on Saturday, but said the company did not shut down the pipeline until 6:01 a.m. – more than three hours after the outbreak of ” a low pressure alarm indicating a possible problem. – and did not report the leak to the Coast Guard until 9:07 am Federal and state rules require immediate notification of spills.
Amplify said the line had already been shut down at 6 a.m. and then restarted for five minutes for a ” meter reading “ and closed again. A meter reading shows the amount of oil entering and leaving the line. The company could have used this information to confirm whether the pressure change alarm went off because the pipe was leaking, Krishnamoorti and Kuprewicz said.
The company said a boat discovered oil on the water at 8:09 a.m.
Willsher, who answered questions alongside the Coast Guard and other officials for four days, did not appear at Thursday’s press conference. Other officials refused to explain his absence.