A water and oil spill from a damaged, abandoned Chevron Corp. well in the San Joaquin Valley has leaked around 24,000 barrels since it was reported in May, but stemming the flow has proved to be a challenge.

The leak from the well in the Cymric oilfield in Kern County remained mostly water (70%) as of last Friday, state officials noted. The incident, which occurred at a site 35 miles west of Bakersfield, is about 3.5 miles from the town of McKittrick and about six miles from the nearest farm.

Flow from five surface expressions was being contained in an earthen dam, according to the California Division of Oil, Gas and Geothermal Resources (DOGGR). “A combination of shutting in nearby injection wells and activating idled production wells to ease pressure on the formation appears to help stem the flow,” officials noted.

Chevron also was deploying loud air cannons to keep wildlife away, and vacuum trucks were removing the pooled oil and water. Preparation to remove contaminated soil from the site was underway last week, and a licensed civil engineer is to survey the site to determine when it would be safe to bring in the crews and equipment.

Chevron said initial efforts to confirm the source of the original leak resulted in higher flows. The spill was on about an acre, and most of the material had been recaptured as of last week.

“There are no reported injuries or threats to drinking water or to waters of current or future beneficial use at this time,” DOGGR noted.

A unified command, comprised of DOGGR, the California Department of Fish and Wildlife's Office of Spill Prevention and Response, Kern County Public Health Services Department and operator Chevron USA Inc. is reporting on the status of the oil spill and clean-up.

Because of the unified command, which was established on July 22, Chevron may not comment separately about the spill, a spokesperson told NGI’s Shale Daily. Under the unified command, “all entities” are required “to speak with one voice…”

DOGGR in May issued a notice of violation (NOV) to Chevron, followed by a second NOV in mid-June. Earlier this month in a formal order, acting Oil and Gas Supervisor Jason Marshall directed Chevron to “take all measures necessary” to curtail any flow from surface expressions and prevent any new surface expressions near the current expression.

Chevron was ordered to submit data to validate the initial root-cause analysis presented to DOGGR in June. In addition, DOGGR requested data to re-evaluate three existing underground injection projects in and around the surface expressions, as well as geologic data and results from monitoring systems that Chevron uses to prevent surface expressions.

Chevron said it was appealing the state order as it lacks some specifics.

"This required remedial action is vague as to, among other things, the meaning of 'all measures' and 'near the subject well,'" Chevron said in its intent to appeal. The company requested "clarity as to what DOGGR is asking it to do."

State officials called the Chevron leak “historic” when compared to two leaks in 2015 and 2016, but the previous leaks were mostly oil. About 3,000 bbl was leaked from a Plains All American pipeline in Santa Barbara County, which resulted in a cleanup, fines and criminal charges for more than $250 million. There also was an oil spill in 2016 of less than 1,000 bbl from a Crimson Pipeline LLC leak in Ventura County.

The San Ramon, CA-based supermajor has about 3,600 plugged wells in the Cymric field; California has a total of more than 120,000 plugged wells statewide.