further constrain a site.
• Creating well standards. This goal addresses the need
to revise standards for casing, cementing, and reworking
wells to tubing-and-packer designs, ensuring no single point
of failure will compromise the well.
• Developing testing, monitoring, and risk mitigation
plans. This goal seeks to clarify the methods, timing, and
protocols for leak detection, mechanical integrity testing,
and corrosion and valve testing. It also specifies improvements in risk management plans, such as what should be
included and how often plans should be reviewed by the
operator and reevaluated by the regulator to promote focus
on a dynamic risk management plan that addresses potential hazards.
• Improving emergency response plans. The revised regulations emphasize strengthening this area to improve public
health and safety, including specifying contingency plans,
notification plans, and equipment and deployment plans.
Also important is clarifying how the operator engages with
incident command and regulatory bodies.
Independent studies have highlighted the need to include issues beyond well integrity to ensure the reliability of
storage facilities. Gas or liquids can escape confinement via
multiple mechanisms including accessing faults and fracture
sets, 10-12 confining zone caprock top-seal sequence failure,
and structural spill points. Failures of reservoir integrity and
gas leaks are well documented for all main types of gas storage site: including depleted oil and gas fields, salt domes,
and mined caverns (Fig. 3). 13 14 Standard practices for risk
management include multiple-barrier models such as bow-ties15 and workflows that include well integrity, reservoir integrity, and operational-organizational elements.
Well integrity is obviously central to the safe and reli-
California, independent studies
able operation of underground natural gas sites. But other
technical and organizational elements have been noted in
some pushback from industry as they could likely add cost
and reduce deliverability of gas in storage. The report notes
that PHMSA will consider the task force recommendations
in developing future regulation and safety standards as re-
quired by the PIPES Act.
The Aliso Canyon event prompted extensive modifications
to California’s regulations for underground natural gas storage sites. External expertise from DOE’s national laboratories supported efforts to stop the blowout. Clearer lines of
authority were drawn between the many state agencies that
regulate storage, including the Department of Conservation’s
Division of Oil, Gas and Geothermal Resources (DOGGR)
and the Public Utilities Commission, to promote better coordination in the event of future leaks.
California implemented two major regulatory changes in
2016. The first was a set of emergency regulations, in force
through at least 2021, intended to safely restart Aliso Canyon. These emergency regulations also led to a comprehensive safety review of the site, requiring that each of the 114
active wells at Aliso Canyon either pass a thorough battery
of tests to resume gas injection or be taken out of operation
and isolated from the underground gas reservoir. 8 The review also required the establishment of a facility-wide emergency response plan and a safety and spill prevention plan.
The second set of regulations applied lessons learned
FIG. 3 STORAGE REGULATION TIMELINE
from the Aliso Canyon event to all of California’s storage
sites. 9 California has 14 underground natural gas storage
projects in 12 fields with a capacity of 385.4 bcf. About 350
active wells are associated with those fields. The four regula-
tory goals include:
• Clarifying data standards. This sharpens the focus on
both area of review, ensuring that injection remains con-
fined to the intended zone, and geologic hazards that may
2016 2017 2018
Q1 Q2 Q3 Q4 Q1 Q2 Q1 Q2 Q3
January: Industry groups
petition PHMSA to adopt
APR RP 1170, 1171
Aliso Canyon event
Jan. 18: All
must be in
Feb 16: California
July 16: California
issues draft regulations
for all other storage
facilities in the state