(California) Onshore Well Regulations: Underground Gas Storage

Last updated: 11 December 2020

Strengthens underground gas storage (UGS) regulations to ensure well integrity and prevent and detect methane leaks, following a catastrophic well failure and leak at a storage facility near Los Angeles in 2015-16.

Regulators must approve UGS projects, review facilities at least once every 3 years for compliance with the approval letter, and can direct a UGS to cease operations for violations or where threats “to life, health, property, the environment, or natural resources” exist (1726.2).

Each UGS project shall submit a Risk Management Plan to the regulator for approval, to ensure stored gas remains in the reservoir. Requires periodic risk reviews (at least once every 3 years) (1726.3).

The operator shall also submit an emergency response plan, with a schedule for response drills. Leaks and well failures, as well as fires, blowouts, and explosions, are possible emergency scenarios (1726.3.1).

The operator shall submit data to demonstrate the gas remains confined, including: the reservoir’s storage capacity; safety devices, tests and precautions; produced water disposal method; reservoir pressure limits; an engineering and geological study indicating the reservoir and each well casing is sound; a gas storage injection and withdrawal plan; and the name and identifying number for each storage well. Updates are required; all submissions shall be made electronically (1726.4).

“Operators shall design, construct, modify, and maintain gas storage wells” to ensure integrity (1726.5), and conduct mechanical integrity testing on every gas storage well (or other unplugged well that reaches the reservoir): annual temperature and noise logs; biannual casing wall thickness inspections; and pressure testing as required under the Risk Management Plan (1726.6).

Methane monitoring requires that the UGS operator:

• Measure well pressure and record at least once a day;

• Conduct real-time data gathering (i.e., sensors and alarms);

• Notify the regulator if there is an unintended gas release “of any size” (1726.7; 1726.9 specifies report content); and

• Follow an LDAR regime approved by the regulator.

Safety valves shall be installed on gas storage wells and tested every six months (1726.8).

An operator must submit a Decommissioning Plan before shutting down a facility (to facilitate effective plugging and leak prevention) (1726.10).

The regulator is the Division of Oil, Gas, and Geothermal Resources (DOGGR), part of the California Department of


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