reservoir. An example would be third party damage, such as
vehicular impact to a wellhead (well risk) or a third party oil
and gas producer drilling through the storage reservoir to a
deeper formation (reservoir risk).”
In addition to the material contained by reference in the
API RPs, PHMSA has mandated specific reporting require-
ments by storage operators that will contribute to a system-
atic national database for wells and reservoirs-caverns. The
four new reports are:
• Annual reports that document operator name, address,
and contact information; site location; number of injection,
withdrawal, and observation wells; and operational informa-
tion including gas storage volumes, pressures, well depths,
injection and withdrawal rates, and maintenance schedules.
• Incident reports filed to document unintentional gas
releases, death or serious personal injury, and substantial
property damage.
• Safety-related condition reports that note pertinent issues such as corrosion of casing or tubing, mechanical defects in wells, earthquakes, or other aspects that may compromise the structural integrity or reliability of the facility.
• National Registry information that associates a storage
operator with an assigned Operator Identification Number
(OPID).
Recordkeeping requirements for operators include assessment, monitoring, planning, and actions taken to maintain safety.
DOE ITF
The US Department of Energy (DOE) and PHMSA created
a joint interagency task force to examine the Aliso Canyon
event in particular and the safety of underground natural gas
storage sites in general. The task force’s report provides a detailed description of the event as of mid-2016 and provides
44 specific recommendations to promote safety of underground storage sites. 7 These recommendations centered on:
• Well integrity, with 13 recommendations including inspection, testing, risk management, monitoring, research,
and data gathering.
• Reliability, with 11 recommendations including new
analytical and planning tools for contingencies, variability
in gas deliverability, and market conditions.
• Health and environment, with 20 recommendations including setting up advisory groups, unified commands for
emergency response, monitoring networks, data access and
timeliness, baseline data, and coordination between the operator and relevant regulatory bodies.
The report recommended in particular that operators
develop and implement comprehensive risk management
plans that are reviewed regularly by the appropriate regulator. Phasing out single-point-of-failure well designs, such as
by installing downhole (subsurface) safety valves, and converting existing wells to tubing-and-packer configurations,
was also recommended. The latter two changes are receiving
• Surface.
Third-party damage.
Surface encroachment.
Intentional, unintentional damage.
Outside force; natural causes such as weather, ground
movement.
• Reservoir.
Third-party damage.
Drilling, completion, and workover activities.
Production, injection, or disposal operations.
Geologic uncertainty.
Extent of reservoir boundary.
Expansion, contraction, and migration of storage gas.
Caprock failure.
Contamination of storage reservoir by foreign fluids;
wellbore damage or corrosion.
• Wells.
Well integrity; corrosion, material defects, erosion,
equipment failure, annular flow.
Design.
Operations, maintenance.
Intervention.
Third-party damage.
Outside force; natural causes such as weather, ground
movement.
The API RPs generally are more detailed for well integrity
than for reservoir integrity. This difference is echoed in a
document published last year as a companion to the RPs by
several industry groups including the American Gas Association. 6 This document states: “Developed under a joint effort
of regulators and industry, API 1170 and API 1171 are based
on the premise that well life cycle integrity management requires good design, construction and operating practices.
For the operations life cycle stage, site-specific risk assessments and integrity program and plan inspection, monitoring, testing and well intervention and remediation tasks are
to be based on the operator’s risk assessments, knowledge,
experience and skill.” The white paper further notes that
“The risk-based approach to well integrity management advocated in API 1171 includes five steps: 1. Data Collection,
Documentation and Review, 2. Hazard and Threat Identification, 3. Risk Assessment, 4. Risk Treatment—Developing
Preventive and Mitigative Measures, and 5. Periodic Review
and Reassessment… The operator’s risk assessment must
take a holistic approach to storage well and field integrity
to effectively manage risk. It should be noted that while this
(white) paper is focused on addressing the integrity of storage wells, some of the threats and preventive and mitigative
measures pertain to both the storage wells and the storage
