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A worker works on an oil rig owned by Sunset Exploration, which is drilling for oil on the western piece of a 2,400-acre swath of property formerly known as the Brentwood Oil Field in Brentwood on May 2, 2013. The fields, once mined by Shell Oil Company and Occidental Petroleum, boomed in the 1960s and have produced 9.8 million barrels of oil.

ANTIOCH -- This struggling city once envisioned a seemingly endless row of homes dotting its southeast hills that would fuel its continued growth and prosperity. But with the housing boom gone bust, a new vision for the landscape has emerged: oil rigs.

Antioch, which long ago abandoned its petroleum roots as its population boomed, is once again looking for a little Texas Tea to pump up its finances.

Sunset Exploration drilled an exploratory well deep into the ground the past two weeks hoping to find pockets of oil hundreds of feet below the surface. While it's still too early to tell whether significant oil reserves will be found, optimism is growing that Antioch could soon become one of the few Bay Area cities pulling petroleum out of the ground.

The property that Sunset is leasing from Shea Homes and Dividend Homes is about a half-mile west of Kaiser Permanente's medical center and is on the fringe of what was known as the Brentwood Oil Field. Once drilled by Shell Oil Co. and Occidental Petroleum Corp., the site boomed in the 1960s and produced 9.8 million barrels of oil, the most of any field in Northern California.

"The easiest place to find acorns is under an oak tree, so we're hoping that the easiest place to find oil is where it's been found before," Sunset President Bob Nunn said. "(The area) used to be pretty prolific."

While oil drilling is common in Southern California and the San Joaquin Valley, it is almost unheard of in the Bay Area.

"From a historic perspective, it's fairly rare," said Tim Kustic, the state's supervisor of the Oil, Gas and Geothermal Resources, a division of the Department of Conservation.

With the exception of some wells in outlying parts of the Bay Area -- including Brentwood and far east Contra Costa County, Rio Vista, the hills east of Livermore and along the coast near Half Moon Bay -- the region is relatively untapped. The likely reason is the area's geology and subsurface foundation, Kustic said.

Further, Kustic said, petroleum excavation tends to occur in Southern California, whereas Northern California wells primarily produce natural gas.

"(Northern California) has never been a major oil-producing province," Kustic said.

The first crack at finding black gold didn't hit pay dirt. But Nunn says there are "some encouraging signs" that oil could be there.

After digging a 4,000-foot-deep hole at a 30-degree angle (to keep machinery far away from a nearby subdivision), the sand below the layers of shale was thicker than anticipated. It had some "minor hydrocarbon shows," or traces of oil, Nunn said.

"We think we found something worth pursuing," he said.

The next step, Nunn said, is to further study the geology of the area based on information gathered from the dig and come back in a couple months to drill another bore nearby.

When Antioch annexed part of the field in 1994, the wells were defunct. The city banned mineral extraction in anticipation of residential and commercial growth.

City leaders repealed the ban in 2005 when development plans stalled.

"It's an interesting opportunity," Councilman Gary Agopian said. "Here's an example of where the community has been challenging us to find ways to improve economic development, and maybe this could help generate a little revenue for the city. There might not be anything there, but then again, hopefully, there might."

"It's not going to be a budget maker," adds City Manager Jim Jakel, "but it could bring in some money, no doubt about it."

Antioch's zoning administrator granted a temporary permit in March for Sunset to drill on 157 acres west of where oil companies once tapped the ground, renewing a 2008 city approval.

Arne Simonsen, Antioch's city clerk and a city councilman from 2000 to 2008, says he supported the drilling as a way to reduce foreign dependence on oil and natural gas.

Simonsen said the hills between Antioch and Brentwood, now covered with homes, were full of oil derricks when he moved to Antioch in the 1970s.

"They may as well take advantage of the open space to extract minerals while they can, before the housing boom comes back eventually," Simonsen said.

Sunset did not move right away on the previous approval because other projects in Southern California took priority, Nunn said.

Sunset is hoping to take advantage of an increase in California crude oil prices, which now top $100 a barrel, especially given that it costs the same to drill for less-lucrative natural gas. That spike has led many companies in the state to invest in more wells, particularly at or near sites that have paid off in the past.

Nunn says the western area of the field has yet to be tapped, which he hopes means there's still oil far below the surface.

"It's an exciting play," he said.

If oil is found, it would be stored in a tank on-site, with the liquid inside drained and taken off-site by trucks once a day. The gas would be funneled through existing underground lines that run under Deer Valley Road.

Before starting to dig, a public meeting was held to vet concerns, particularly those from residents who live about 1,500 feet away in homes on Mammoth Way. In the past, residents there have expressed concern about noise and soil contamination. Only one person attended the meeting.

A recent visit to the site found that the 100-foot-high rig and other heavy machinery were relatively loud on the site but cannot be heard from Mammoth or Deer Valley.

"We're trying to be good neighbors," Nunn said.

Contact Paul Burgarino at 925-779-7164. Follow him at Twitter.com/paulburgarino.