State Hunts Leaks, Won’t Let Seeping Gas Bogs Lie
As aging oil pumps slowly heaved in the background, Fleet Rust collected a syringe full of gas from a probe drilled two feet into the ground.
Rust took the sample to a nearby camper and inserted it into a gas chromatograph, which analyzes the amount and type of gases in a sample.
Ten minutes later, the machine showed that the largest concentration of the gases being tested for--methane, ethane, propane, isobutane and normal butane--was 6 parts per million of methane.
“It presents no hazard. It could be a little bit of swamp gas, but it’s not dangerous,” said Rust, a chemist for Simi Valley-based Geoscience Analytical Inc., which began collecting gas and soil samples from an oil field near Norwalk Boulevard and Telegraph Road last week.
The samples being taken at the field in Santa Fe Springs are part of a study that was commissioned by the state Division of Oil and Gas to look for hazardous concentrations of gases near abandoned oil and gas wells.
The $250,000 study--prompted by emergency legislation passed last year--requires the division to identify sites where there are potential gas hazards and develop a strategy to extract the gases to prevent dangerous buildups. Eight sites in Santa Barbara, Los Angeles and Orange counties are being studied.
The legislation, authored by state Sen. David A. Roberti (D-Los Angeles), stemmed from an incident in March, 1985, in Los Angeles’ Fairfax District in which 22 people were injured when an accumulation of methane gas exploded at a Ross Dress for Less clothing store. About 160 buildings were evacuated as fire continued to burn the next day through cracks in the sidewalk.
“The explosion triggered the whole process,” said Bill Guerard, a senior engineer with the oil and gas division’s Sacramento office. A final report by Geoscience, which started its work for the state in January, is due Oct. 1.
“It is a study that is much needed,” said Richard Manuel, an operations supervisor with the gas and oil division’s Long Beach office.
“One of the problems with the Los Angeles area, and Fairfax in particular, is that it’s a natural seepage area. The buildings, parking lots and streets have formed a cap over the area that doesn’t allow natural seepage,” Manuel said. “Once it is trapped, it accumulates . . . and travels along until it finds a place to come out.”
Officials say the gases seeping into the air do not present a danger because they are generally released in low concentrations. The danger occurs when the gases are not allowed to vent, paving the way for a possible explosion.
“The fields are being sold off and developed. The state wants to be sure there aren’t any bad seeps or hazardous concentrations of gas,” Rust said.
The state agency used various criteria to compile a list of potential sites. Among the sites it singled out for attention were those near old wells abandoned before 1930 or those near an urban site where there is a history of natural seepage, Guerard said.
So far five sites have been studied by Geoscience. Cursory analysis showed that the sites in Santa Fe Springs and Whittier--the only sites being studied in the Southeast and Long Beach areas--and Summerland in Santa Barbara County, have low concentrations of gas. However, there were substantial amounts of gas in sites in Newport Beach and Brea, said Louis Pandolfi, vice president of operations for Geoscience.
Guerard said that where heavy concentrations of gas are found, the most likely solution would be to drill pressure relief wells or install a vacuum pump system to safely release the gas and reduce buildup.
When It Is Hazardous
Pandolfi said if the amounts of methane reach 100 parts per million, “it starts to be a hazardous anomaly.” Methane becomes explosive at 50,000 parts per million.
The city of Newport Beach, where levels up to 50,000 parts per million were detected, is “already drilling wells to reduce the pressure and vent the gas,” Pandolfi said. “They are tackling it as an emergency.”
The Santa Fe Springs study could not have come at a better time for the city.
Richard Weaver, director of planning and development, said the city had sent out requests for proposals to study oil fields and landfills in December when it learned about the pending state study. The city decided to hold off on its study until after the state finished theirs, he said. The city may just use the information contained in the state study, he added.
The information will be used to see “if there are potential hazards from the leakage of methane gas from old wells,” Weaver said. Construction is now taking place at various old oil sites in the city.
Project on Oil Field
One of the biggest projects in the city, the Heritage Corporate Center on the corner of Norwalk and Telegraph boulevards, sits on an old oil field, Weaver said. Construction began last month on the 67-acre site, which will eventually house office and industrial buildings, restaurants, a health club, a day-care center and historical park.
“If there are hazardous conditions, we need to know that,” Weaver said. The city was considering asking the state to expand its study in Santa Fe Springs to include landfills. But the state air quality control agency will be doing a similar study on landfills in the area, including one in Santa Fe Springs, Weaver said.
During earlier sampling at a different location, Rust said, he found a concentration of 1,000 parts of methane per million in the Santa Fe Springs oil field. It isn’t dangerous now, he said, but “it might be if someone built something and trapped” the gas. “Right now it’s going into the atmosphere and it’s not a problem.”
He said development can still occur even if seepage is found, but it must be built in such a way that it allows the gas to vent itself. Builders need “to be aware of the problem” when they are contemplating the construction of a building, parking lot or other structures, Rust said.
Rust is supplementing gas samples with selected soil samples to detect the source of any gas found. The source of the gas and possible solutions will be included in the study.
For example, he said, if gas is naturally seeping, it will only require a shallow vent to allow it to escape. But if the gas stems from an oil or petroleum source, a deeper well must be built to remedy the accumulation of gases.
Manuel said that if a development is built over an abandoned well, the agency must inspect it to see if it has been correctly capped to prevent leakage.
“I don’t recommend building over an old oil well,” said Manuel. But the division does “not prevent it.”
“Any time you disturb nature, there’s always potential for a problem,” he said.