When searching for new pools or pockets of oil and natural gas, petroleum companies leave few stones unturned.
In Southeast Los Angeles County, big oil producers have added a twist to that adage: They have left few slices of crust untested.
The latest survey of the earth's top layer is under way in the county's southeastern suburbs as a geological testing company hired by Texaco U.S.A. Inc., crisscrosses the area to probe the underground rock formations for oil and gas deposits long since passed over by earlier explorers.
In recent weeks, Geophysical Service Inc. has used sound waves to map the vast regions beneath the tracts of homes, businesses and schools in La Mirada, Bellflower and Artesia. Later this summer, the Santa Fe Springs-based firm will conduct similar tests in Downey and Norwalk for Texaco, the nation's third-largest oil producer.
"We don't think there is another Prudhoe Bay down there--but it would be nice if we stumbled onto one," said Texaco spokesman John Aucott, referring to the mammoth oil and natural gas field on Alaska's mineral-rich North Slope. "This is strictly routine testing to see if we've missed anything in the past."
Aucott said new techniques in oil exploration make retesting of areas--even those that have shown little or no promise in the past--potentially profitable if a new reservoir of crude or natural gas is found.
City officials and area historians say oil companies have periodically scratched the surface and poked instruments in the ground from Whittier to Signal Hill and Long Beach since the turn of the century, when petroleum became a prized commodity.
How Procedure Works
The latest tests, completed a week ago in Artesia and Bellflower, use sound waves to record the geological makeup of the earth's interior just below the surface, said Texaco geophysicist Doug Barman. Telephone receivers, known as "geophones," attached to a monitoring device are placed along a quarter-mile stretch of street. A special pad is then set on the pavement. A large, heavy truck, similar in size and weight to a dump truck, parks on the pad, which is vibrated to send sound waves rippling into the ground.
Barman said the geophones measure how long it takes for those sound waves or vibrations to return to the surface. Scientists then take the recordings and draw a "picture" of the rock formations to determine if any contain oil or gas deposits. Sound waves pass through some rocks more quickly than others.
Like an Echo
"It's a bit like standing on the edge of a canyon and shouting across," Barman said. "You can tell how deep and wide the canyon is by how long it takes for your echo to rebound. It's like we're taking a snapshot of the earth's interior."
Test results won't be known for weeks, and even if an area looks promising, Aucott said it would be months before any drilling would occur. He said the area would be retested to verify the original findings and then the property owner must give his permission to lease his land to the oil company for exploratory drilling.
If oil or gas is discovered, Aucott said there are a number of ways to extract the minerals--such as directional or slant drilling--even if the surface has been built on. "If it's there, we can get it without tearing down homes or businesses," he said.
Because the vibrations in the testing procedure can last several seconds, Geophysical Service suggests residents and merchants remove delicate objects from shelves. About 48 hours before testing begins, the company normally distributes a leaflet explaining the purpose of the testing and its effect.
While the tests usually cause little or no damage, some residents have complained of earthquake-like shaking, and in Artesia a body shop on Artesia Boulevard had to shut down for a day recently after vibrations knocked several paint compressors off a counter. City officials said Geophysical Service quickly paid the $1,200 bill to repair the damaged equipment.
"We had a few calls from people concerned about their houses rattling," said Tom Robinson, the community resource manager in La Mirada, where Geophysical ran tests a month ago. "We reassured them, telling them it's legal and safe. And we tell them the process is like trolling for fish. They are just testing the waters."
Inactive for Decades
In the Southeast area, most oil production has been in the Coyote Fields, which stretch east from south Whittier, La Mirada and Santa Fe Springs across the county line to the hills above Fullerton in north Orange County. But most of those wells have been inactive for several decades. "The oil boom in this area was in the 1920s, when this was ranch land," said Bob Camp, a La Mirada historian. "Now there are only a few wells pumping. Lots of the wells have been replaced by homes and stores."
But that hasn't discouraged companies like Texaco from hoping for a new strike.
"Because the whole Los Angeles basin has been such a prolific producer of oil, there is a reasonable expection of finding more," Aucott said. "That's why we take the gamble."