Scientists Say Oil Rigs on Shaky Ground : Earthquakes: The pair warn that of 32 offshore platforms, 12 are old and should be reinforced. But the industry disagrees.

Aging oil platforms along the Southern California coast could collapse during a major earthquake, killing workers and spewing oil into the ocean, according to two scientists whose conclusions have sparked intense debate within the oil industry.

The scientists say that 12 of the state’s 32 oil platforms--three-fourths of which are off Ventura and Santa Barbara counties--were constructed to standards now obsolete and should be reinforced to ensure their stability during the type of earthquake that struck the San Francisco Bay Area in 1989.

“We’re saying, ‘You guys have got to learn to do your business in a responsible way,’ ” said Robert G. Bea, a UC Berkeley professor and former chief engineer for Shell Oil Co.

“The question is how do we bring these platforms up to speed? And what is safe enough?” said Bea, director of the Marine Technology Development Group at Berkeley.

Bea has emerged as a leading advocate for tougher standards in an increasingly volatile dispute over the strength of California’s oldest offshore oil platforms--those built between 1958 and 1969 before the petroleum industry adopted a uniform design code for the rigs.

Bea, former state geologist James E. Slosson and representatives of the state Seismic Safety Commission have urged government regulators to stiffen structural standards for offshore platforms to prevent a possible environmental catastrophe during a major earthquake.

In response, spokesmen for the oil industry and for government agencies that oversee offshore platforms in California said they are satisfied that the older platforms could withstand enormous earthquakes without collapsing.

And even if a platform collapsed, the effects would be minor because the old platforms are drawing oil from nearly depleted wells that would not continue to flow if pumping halted, they said.

“We are safe against very large earthquakes,” said Michael Craig, a civil engineering consultant for Unocal.

Unocal operates five of the 12 pre-1970 platforms, and all could withstand the equivalent of a 7.0-magnitude temblor whose epicenter was just three miles away, Craig said. Projections are that such a quake would occur once in tens of thousands of years, he said.

Charles E. Smith, program manager for operational safety at the U.S. Minerals Management Agency, said his agency’s regulatory standards for offshore platforms are sufficient.

“As far as I’m concerned, everything is working just fine,” Smith said. “We feel the criteria we have is sound.”

The debate over platform safety has accelerated as new studies have found that coastal Ventura County is the second most hazardous earthquake zone in Southern California, trailing only areas near the San Andreas Fault.

The core of the debate--and one of the hottest topics in offshore engineering--is whether some small risk of an oil spill or worker deaths is acceptable given the enormous costs of upgrading offshore platforms.

Bea estimates it would cost an average of $20 million to bring the old platforms up to standards that oil companies use today. New platforms can withstand virtually any earthquake, he said.

Following the 7.1-magnitude Bay Area earthquake nearly two years ago, both the Minerals Management Agency and the State Lands Commission began to re-evaluate the strength of the 12 oldest rigs off California. Of all 32 platforms, nine are within three miles of shore, in state jurisdiction. The other 23 are more than three miles offshore in federal waters.

Critics such as Bea and Slosson, however, have maintained that the regulators’ minimum standards are too low. And they contend that computer projections of how often a major temblor will strike are only educated guesses because so little data exists on ruptures along offshore faults.

“We’ve adopted this simplistic, almost primitive approach” to determining platforms’ resistance to earthquakes, Bea said. “We need to move on to something better.”

Slosson, a geophysicist who has worked as an earthquake consultant for local and state agencies, said new regulations should be approved to take away all risk from the use of platforms.

“We’re saying don’t roll the dice, throw the dice away,” Slosson said. “We have the technology, so let’s use it.”

Regulatory agencies should force oil companies to strengthen their platforms to withstand the maximum force that an earthquake could place on the rigs, Bea and Slosson said. Under that standard, the platforms could withstand a 7.5-magnitude earthquake with an epicenter three miles away, Bea said.

The current minimum standard used by both state and federal regulators requires that a platform have enough strength and ductility--the ability to flex without breaking--to resist a 6.5 earthquake centered six to 12 miles away without collapsing, Bea estimated.

An earthquake of 6.5 magnitude, the same size as the 1971 Sylmar temblor, could collapse some old platforms if it struck nearby, Bea said. “If it was centered, say, at the Holiday Inn in Ventura,” he said.

Caltech geophysicist Andrea Donnellan reported last year that a 6- to 7-magnitude earthquake along two Ventura County faults, the Oak Ridge and San Cayetano, is highly probable. She and other scientists, citing new satellite information, have described Ventura County as one of the most earthquake-prone areas in the world.

The last major earthquake in the county was probably in 1812, Donnellan reported. But an earthquake registering 5.9 and centered off Point Mugu caused more than $1 million in damage in the Oxnard-Ventura area in 1973. A 1925 Santa Barbara earthquake registered 6.3, and in 1927, a 7.5-magnitude temblor shook Lompoc in Santa Barbara County.

The eight offshore platforms outside the Santa Barbara Channel area are off Long Beach, Seal Beach and Huntington Beach. They are close to the Palos Verdes Hills and Newport-Inglewood faults. The disastrous 1933 Long Beach earthquake on the Newport-Inglewood Fault registered 6.3.

Regulators say that while seismic activity is high in both the Long Beach and Ventura areas, design guidelines that the old platforms must meet assure that there is only a minuscule chance that a California platform would collapse.

Those guidelines, developed by the American Petroleum Institute (API) and followed by both state and federal regulators in California, require that even old platforms be able to withstand the strongest earthquake that could occur over several hundred to a few thousand years.

Peter Johnson, chief petroleum engineer for the State Lands Commission, said he is not certain what earthquake standard should exist for offshore platforms. But current standards already are much more stringent than building codes used to assure the safety of high-rise buildings in California, he said.

Estimates of the size of an earthquake that could topple a platform vary depending on factors such as soil conditions, landslide potential and the closeness of the temblor, engineers agree.

Though Bea estimates that platforms complying with petroleum institute guidelines could withstand only a 6.5-magnitude temblor nearby, state and federal regulators said they could not reduce their complex list of guidelines to a Richter-scale equivalent.

Unocal consultant Craig, chairman of API’s task force that reviews platform design standards, said Bea’s estimate is irrelevant when discussing Unocal’s five aging platforms, since all could withstand a 7.0 quake centered three miles away.

“These are lean and mean structures,” Craig said. “We don’t have any of the architectural or mechanical worries that structures on shore have.”

Even if an old platform did collapse, the lack of well pressure would keep oil in the ground, he said. Automatic shut-off valves would close off wells and the pipelines to shore, he said. A broken pipeline would not allow much oil to escape, because the oil is so heavy “it would just sit there,” he said.

Bea and Slosson maintained, however, that a platform collapse could lead to the escape of up to a few thousand barrels of oil.

They also insisted that the oil industry and regulators rely too heavily on computer projections. They said that there is not enough data on offshore earthquakes to predict when a devastating quake might occur.

“It’s worse than guessing,” Slosson said of the projections, “because their computer analysis validates erroneous information.”

Industry experts say there is enough offshore data for viable projections. Analysts have data on nearly 800 offshore temblors in the Santa Barbara Channel since 1800, said Thomas Blake, an oil-company consultant.

The issue of adequate platform strength should get a full airing during the next year. It will be the prime topic at an international conference in March.

But Thomas Dunaway, Pacific region supervisor of field operations at the Minerals Management Agency, said that a consensus will be hard to reach.

“Nobody’s ever done this kind of reanalysis (of old platforms),” Dunaway said. “So when you get five different engineers in five different rooms, you can get five different ideas on how to tackle it properly.”

Earthquake Faults in Offshore Oil Fields

Twenty-four of the 32 offshore platforms in California are near Santa Barbara and Ventura counties. Several major earthquake faults are nearby.