A section of the creek bed inundated by an oil spill near a Chevron well in Kern County awaits cleanup in this Aug. 21 image. (California Department of Conservation)
Updated 3:40 p.m. Monday
State oil and gas regulators say they're launching an investigation of operations in a Kern County oil field after a series of large, uncontrolled crude petroleum releases near Chevron wells — including one that has continued on and off for more than 16 years and may have spewed out more than 50 million gallons of crude oil.
The state Division of Oil, Gas and Geothermal Resources, known as DOGGR, served Chevron with a notice of violation on Friday, ordering the company to stop major, uncontrolled surface flows at a site called Gauge Setting 5, or GS-5, in the Cymric oil field. Oil has been flowing from the location since March 2003.
Chevron's Kern County Spill
The order comes as DOGGR says it's stepping up enforcement of a regulation that took effect in April banning the uncontrolled surface flows, which the agency and petroleum operators call "surface expressions."
One such release occurred over the last three months near a damaged and abandoned Chevron well in an area of the Cymric oil field designated 1Y. The flows in that incident, which began in May and stopped earlier this month, dumped about 400,000 gallons of crude into a dry creek bed.
DOGGR has issued two notices of violation so far in connection with the 1Y episode, the precise origin of which is still under investigation.
'Putting an End' to Surface Expressions
In an email Sunday, agency spokeswoman Theresa Schilling said that in light of the April rules barring surface expressions, "DOGGR is looking to put an end to their occurrence."
Schilling also acknowledged that the driving force behind the surface expressions is an oil extraction method that Chevron and other operators in the Cymric field rely on.
The roughly 11,000-acre Cymric field, in the Temblor Range foothills about 35 miles west of Bakersfield, is the scene of extensive steam injection operations— a technique in which high-pressure steam is forced deep into the ground to free oil trapped in underground formations.
Normally, that freed crude petroleum is pumped to the surface through well bores and shipped by pipelines or tankers for processing. But that's not what's been happening around the leaking Chevron wells, where crude oil, steam and water have apparently moved laterally underground until they find a vent or create a sinkhole that allows the material to come to the surface.
"The steam injection wells are the source of heat and pressure that drive surface expressions," Schilling said Sunday. But she added that further investigation is needed to understand exactly how that underground heat and pressure is resulting in the surface flows.
To get to the bottom of the expressions, Schilling said, DOGGR "is exploring swift next steps to evaluate and investigate the oil field as a whole." She said that investigation will include independent experts, including staff from Lawrence Livermore and Lawrence Berkeley national laboratories.
The uncontrolled flows at sites GS-5 and 1Y — locations that are just 1,000 feet apart in an area studded with dozens of active and abandoned steam injection wells — will likely be at the center of the investigation.
GS-5 is the site of a flow that began in March 2003 and has recurred in a series of surface expressions in the immediate vicinity. In response to the flows, Chevron built a collection facility in 2012 from which oil is pumped into a pipeline or sucked up by vacuum trucks for processing.
84 Million Gallons Released
A Chevron spokeswoman said Sunday that about 2 million barrels of oil and water — 84 million gallons have come to the surface at GS-5 since March 2003.
The company told DOGGR last year that it estimated the liquid flowing at the site to be 60% to 80% oil. At At the lower concentration level — 60% oil — that would put the volume of crude that has come to the surface at about 50 million gallons.
Chevron data provided to DOGGR shows the amount of liquid flowing at GS-5 has increased dramatically in recent years, from an average of about 250 to 1,100 barrels a day. The flow appeared to spike this summer after the May 10 appearance of the new surface expression at site 1Y, at one point hitting 3,000 barrels — 126,000 gallons — a day.
"Chevron’s operational priority is the prevention of all seeps," company spokeswoman Veronica Flores-Paniagua said in an email. "We are committed to stop this seep and are working toward that goal. There has been no impact to personnel, groundwater, surface water, wildlife or agriculture" from the GS-5 releases.
DOGGR's notice of violation for the GS-5 surface expressions came as yet another uncontrolled release appeared near a Chevron well in Cymric field. The new spill, consisting of about 14,000 gallons of oil and water, appeared late Aug. 21 about 750 feet from GS-5 and 1,800 feet from 1Y.
DOGGR issued a notice of violation against Chevron for the new spill.
The agency has ordered Chevron to explain what caused the most recent release and halt steam injection work 300 feet around it, among other orders.
Status of Cleanup
On Friday, KQED reported that state regulators said they did not how how long it would take for crews to clean up the 1Y spill that started in May.
Those flows, from half a dozen separate points, dumped crude oil and water into about 1,000 feet of a stream bed that runs from the flank of the Temblor Range toward the San Joaquin Valley to the east. At the site of the spill, the seasonal creek runs through a maze of oil wells and pipes used in the steam injection and oil recovery process.
Drone video recorded last week shows that crews using bulldozers and other heavy equipment have removed contaminated soil from roughly 600 feet of the creek bed.
Department of Fish and Wildlife spokesman Eric Laughlin said in emails over the weekend that work to clean up the rest of the befouled stream bed has been suspended for the time being.
"Cleanup operations have been on hold so that wells in the area can be diagnosed to determine the cause of the expressions," Laughlin said.
That investigative work could lead to more releases, Laughlin said. Once the work is done, the cleanup will continue, he said.
State officials have come under increased scrutiny for their oversight of oil and gas drilling in recent months.
In mid-July Gov. Newsom fired the head of DOGGR in the wake of disclosures the agency had dramatically increased the number of fracking permits it was issuing and that some agency employees owned stock in the companies they regulate.
Earlier this month California Natural Resources Secretary Wade Crowfoot said his agency would investigate DOGGR's issuance of so called "dummy files" to petroleum companies after the Desert Sun reported that the agency may have granted permits for steam injection oil operations without doing the required safety review.
Story updated at 3:40 p.m. Monday to clarify the source of Chevron's estimate that the flow at site GS-5 is 60% to 80% oil.