COLORADO OIL AND GAS
CONSERVATION COMMISSION
CLASS II UNDERGROUND INJECTION
CONTROL
RULES AND REGULATIONS
Garfield County Energy Advisory Board
Thursday, October 7, 2010
David Andrews, P.E., P.G.
Western Colorado Engineering Supervisor
FEDERAL UNDERGROUND INJECTION
CONTROL (UIC) REGULATIONS
• 40 CFR 144 – Underground Injection Control
Program
• 40 CFR 145 – State UIC Program Requirements
• 40 CFR 146 – Underground Injection Control
Program: Criteria and Standards
• 40 CFR 147 – State, Tribal, and EPA-Administered
Underground Injection Control Programs
– Subpart G - Colorado
UIC WELL CLASSES
• All underground injection wells are regulated by the
U.S. EPA
– Class I: wells used to inject hazardous waste or industrial
waste below an Underground Source of Drinking Water
(USDW)
– Class II: wells used to dispose of exempt oil or gas waste
fluids or wells used for enhanced oil recovery
– Class III: wells used for solution mining
– Class IV: wells used to inject hazardous waste or industrial
waste above a USDW (banned except for those which are
part of an EPA or state approved CERCLA or RCRA project)
– Class V: all others or wells used to inject nonhazardous
fluid into a USDW
– Proposed Class VI: wells used for underground injection of
carbon dioxide for sequestration
STATE PRIMACY
• U.S. EPA often delegates regulation of UIC
wells to individual states (primacy)
• U.S. EPA delegated primacy to COGCC for Class
II UIC wells on April 2, 1984
• U.S. EPA sometimes delegates primacy for
other classes of wells to individual states (e.g.,
Wyoming has primacy over some Class V
wells)
COLORADO STATISTICS
• COGCC currently regulates more than 800
Class II UIC wells in Colorado.
• Approximately three-quarters of these wells
are enhanced recovery wells
COLORADO REGULATIONS
• Rule 325 defines notice requirements for Class II
UIC wells:
– Written notice to surface owners and mineral owners
is required within ¼ mile of the injection well. The
notification distance increases to ½ mile for any
mineral owners that produce oil or gas from the
injection zone.
– Single-well permits are typically submitted for Class II
disposal wells, but COGCC’s rules accommodate
applications for multiple well units, which are often
necessary for enhanced recovery operations.
– COGCC publishes disposal well notices in a local
newspaper announcing a 30-day public comment
period.
COLORADO REGULATIONS
• Rule 325 requires submittal of downhole
construction methods, surface facility
information, and a list of Class II waste sources:
– Packer, tubing, casing, and cement design details
which demonstrate how the operator will maintain
mechanical integrity of the well and ensure that
injected fluids will be confined to the injection
formation.
– A surface facility diagram showing all pipelines and
tanks associated with the injection system.
– A list of all sources of Class II fluids to be injected, by
lease and well.
– Anticipated injection rates and pressures.
Casing and Cement Design (Conductor)
Casing and Cement Design (Surface)
Casing and Cement Design (Production)
COLORADO REGULATIONS
• Rule 325 requires a successful Mechanical Integrity
Test (MIT) prior to approval of a UIC application, and
Rule 326.a. defines MIT requirements for UIC wells.
– 5-year MIT’s (pressure tests) on the tubing-casing
annulus or monthly pressure monitoring events are
performed to determine whether significant leaks are
present in the packer, tubing, or casing.
– Tracer surveys, cement bond logs, and/or temperature
surveys are also required to determine whether there
are significant vertical fluid movements above or
below the injection formation. Injected fluids must be
confined to the injection formation.
– If a UIC well lacks mechanical integrity, the operator
must immediately cease injection. Injection cannot
resume until the well is repaired and pressure tested.
COLORADO REGULATIONS
• Rule 324B defines requirements for aquifer exemptions
– Water quality test data is required from the disposal
formation.
– If total dissolved solids (TDS) is greater than 3,000
milligrams per liter (mg/l) and less than 10,000 mg/l, then
an aquifer exemption is required in addition to a UIC
permit application.
– COGCC publishes notices of aquifer exemption requests in
a local newspaper for a 30-day public comment period.
– The notice is also forwarded to U.S. EPA for their review.
COLORADO REGULATIONS
• Aquifer exemptions are granted for formations that are
not currently used as a source of drinking water and
meet one of the following criteria:
– The formation contains commercially producible minerals or
hydrocarbons;
– The formation is so deep that recovery of water for drinking water
purposes is economically or technologically impractical; or,
– The formation is so contaminated that it would be economically or
technologically impractical to render the water fit for human
consumption.
• Aquifer exemptions are not approved for formations with
TDS equal to or less than 3,000 mg/l TDS.
UIC PERMIT APPLICATION REVIEW
• COGCC local engineering staff reviews Form 2
(Application for Permit to Drill, Deepen, Re-Enter, or
Recomplete).
• Form 2 review is intended to verify that casing and
cement design is adequate to ensure that groundwater
aquifers, hydrocarbon production zones, and the
injection formations are isolated from each other to
prevent cross-migration of fluids between each zone.
UIC PERMIT APPLICATION REVIEW
• COGCC’s UIC Engineering Supervisor reviews Form 4
(optional, Sundry Notice request to perform injectivity
test), Form 31 (Underground Injection Formation
Permit Application), Form 33 (Injection Well Permit
Application), Form 21 (Mechanical Integrity Test), and
Form 26 (Source of Produced Water for Disposal).
• Form 4 review defines testing limits (duration and
volume) to ensure that the injectivity test approval
does not authorize continuous injection.
UIC PERMIT APPLICATION REVIEW
• During the Form 31, Form 33, and Form 26 review,
COGCC evaluates well construction details and
injection formation water sample results. COGCC
submits a request to the Division of Water Resources
for their opinion regarding the well construction and its
ability to protect groundwater resources.
• COGCC reviews well construction details for all oil and
gas and water wells within ¼ mile of the proposed
injection well. If necessary to ensure protection of
groundwater aquifers and hydrocarbon zones, remedial
work on offset wells may be required by COGCC.
UIC PERMIT APPLICATION REVIEW
• COGCC reviews all mineral and surface owner
notifications and the surface owner agreement or the
BLM Sundry Notice which authorizes surface use of the
facility for injection of Class II waste.
• COGCC evaluates the technical merit of all protests and
public hearing requests. COGCC hearings may be
scheduled for any protests that demonstrate that the
proposed injection well has the potential to cause
injury to mineral or groundwater resources.
STANDARD CONDITIONS OF APPROVAL
• All UIC permits are approved with the following
stipulations:
– COGCC requires financial assurance for plugging and well
reclamation. Additional financial assurance is required for
surface facilities at commercial injection sites.
– COGCC assigns a maximum allowable pressure for continuous
injection, which is set below formation fracturing pressure.
– COGCC assigns a maximum allowable injection volume for
disposal wells, which is calculated to hold the pore volume
within a radius of influence of ¼ mile. There are no volume
restrictions for enhanced recovery wells.
– Operators must monitor and report injected water volumes on a
monthly basis, and water samples are required periodically to
monitor any significant TDS changes in the injected fluids.
UIC ENFORCEMENT
• All UIC wells (disposal wells and enhanced recovery
wells) are inspected annually. Injection pressures and
annular pressures are checked for anomalies and
recorded. Pressure anomalies may indicate that a leak
has developed and the packer, tubing, or casing lacks
mechanical integrity.
• MIT’s are performed on all UIC wells every five years.
Failed MIT’s are an indicator that a packer, tubing, or
casing leak may be present.
• Notices of Alleged Violation are issued for any UIC
wells that lack mechanical integrity. Operators are
required to shut-in these wells until repairs are made
or the wells are plugged and abandoned.
CLASS II WASTE EXEPTIONS ARE DEPENDENT
ON THE FLUID SOURCE, NOT ITS CHEMISTRY
• Class II waste includes waste materials that are
intrinsically derived from primary field operations
associated with the exploration, development, or
production of crude oil and natural gas.
• “Because the RCRA exempt status of an oilfield waste
is based on the relationship of the waste to E&P
operations, and not on the chemical nature of the
waste, it is possible for an exempt waste and a nonexempt hazardous waste to be chemically very
similar.”
CLASS II EXEMPT E&P WASTES
•
•
•
•
Drilling fluids
Rig wash
Produced water
Spent well completion, treatment, and
stimulation fluids
• Accumulations and deposits in tanks and
pipelines used to store or transport Class II
exempt wastes.
• Gas plant dehydration and sweetening wastes
NON-EXEMPT WASTES
•
•
•
•
•
Unused fracturing fluids or acids
Painting wastes
Waste solvents
Refinery wastes
Used equipment lubricating oils and hydraulic
fluids
• Sanitary wastes
• Pesticide wastes
• Radioactive tracer wastes
Questions
Denise M. Onyskiw, P.E.
Colorado Oil and Gas Conservation Commission
303-894-2100 ext. 5145
Denise.Onyskiw@state.co.us