Current through Register Vol. 48, No. 9, September 27, 2024
A. All Class II and
III wells shall be sited in such a fashion that they inject into a formation
which is separated from any Underground Sources of Drinking Water by a
confining zone that is free of known open faults or fractures, or other
geological discontinuities within the area of review.
B. All Class II and III injection wells shall
be cased and cemented to prevent movement of fluids into or between underground
sources of drinking water. The casing and cement used in the construction of
each newly drilled well shall be designed for the life expectancy of the well.
(1) In determining and specifying casing and
cementing requirements, the following factors shall be considered:
(a) Depth to the injection zone;
(b) Depth to the bottom of all Underground
Sources of Drinking Waters; and,
(c) Estimated maximum and average injection
pressures.
(2) In
addition, the Department may consider information on:
(a) Corrosiveness of injected fluids and the
physical and chemical characteristics of formation fluids;
(b) Lithology of injection and confining
zones;
(c) External pressure,
internal pressure, and axial loading;
(d) Hole size; (depth, diameter)
(e) Size and grade of all casing strings;
and,
(f) Type and grade of cement
and additives.
C. Appropriate logs and other tests shall be
conducted during drilling and construction. A descriptive report interpreting
the results of that portion of those logs and tests which specifically relate
to an Underground Source of Drinking Water and the confining zone adjacent to
it, and the injection and adjacent formations shall be prepared by a
knowledgeable log analyst and submitted to the Department. At a minimum, these
logs and tests shall include:
(1) Deviation
checks on all holes constructed by first drilling a pilot hole and then
enlarging the pilot hole, by reaming or another method. Such checks shall be at
sufficiently frequent intervals to assure that vertical avenues for fluid
movement in the form of diverging holes are not created during
drilling.
(2) Such other logs and
tests as may be needed after taking into account the availability of similar
data in the area of the drilling site, the construction plan, and the need for
additional information that may arise from time to time as the construction of
the well progresses. In determining which logs and tests shall be required the
following shall be considered by the Department in setting logging and testing
requirements:
(a) For surface casing intended
to protect underground sources of drinking water in areas where the lithology
has not been determined:
(i) Electric and
caliper logs before casing is installed; and,
(ii) A cement bond, temperature, or density
log after the casing is set and cemented.
(b) For intermediate and long strings of
casing intended to facilitate injection:
(i)
Electric, porosity and gamma ray logs before the casing is installed;
(ii) Fracture finder log; and,
(iii) A cement bond, temperature, or density
log after the casing is set and cemented.
D. At a minimum, the following
information concerning the injection formation shall be determined or
calculated:
(1) Fluid pressure;
(2) Estimated fracture pressure;
(3) Physical and chemical characteristics of
the injection zone.
E.
Operating Requirements. Operating requirements shall, at a minimum specify
that:
(1) Injection pressure at the wellhead
shall not exceed a maximum which shall be calculated so as to assure that the
pressure during injection does not initiate new fractures or propagate existing
fractures in the confining zone adjacent to the Underground Sources of Drinking
Waters. In no case shall injection pressure cause the movement of injection or
formation fluids into an underground source of drinking water.
(2) Injection between the outermost casing
protecting underground sources of drinking water and the well bore is
prohibited.
F.
Monitoring Requirements for Class II Wells. Monitoring requirements shall, at a
minimum, include:
(1) Monitoring of the nature
of injected fluids at time intervals sufficiently frequent to yield data
representative of their characteristics;
(2) Observation of injection pressure, flow
rate, and cumulative volume at least with the following frequencies:
(a) Weekly for produced fluid disposal
operations;
(b) Monthly for
enhanced recovery operations;
(c)
Daily during the injection of liquid hydrocarbons and injection for withdrawal
of stored hydrocarbons; and,
(d)
Daily during the injection phase of cyclic steam operations; And recording of
one observation of injection pressure, flow rate and cumulative volume at
reasonable intervals no greater than thirty days.
(3) A demonstration of mechanical integrity
at least once every five years during the life of the injection well;
(4) Maintenance of the results of all
monitoring until the next permit review; and,
(5) Hydrocarbon storage and enhanced recovery
may be monitored on a field or project basis rather than on an individual well
basis by manifold monitoring. Manifold monitoring may be used in cases of
facilities consisting of more than one injection well, operating with a common
manifold. Separate monitoring systems for each well are not required provided
the owner/operator demonstrates that manifold monitoring is comparable to
individual well monitoring.
G. Monitoring Requirements for Class III,
IV(2)
(a) and V.A. Wells.
(1) An appropriate number of monitoring wells
shall be completed into the injection zone and into any underground sources of
drinking water which could be affected by the injection operation. These wells
shall be located in such a fashion as to detect any excursion of injection
fluids, process by-products, or formation fluids outside the injection area or
zone. If the operation may be affected by subsidence or catastrophic collapse
the monitoring wells shall be located so that they will not be physically
affected.
(2) In determining the
number, location, construction and frequency of monitoring of the monitoring
wells the following criteria shall be considered:
(a) The population relying on the USDW
affected or potentially affected by the injection operation;
(b) The proximity of the injection operation
to points of withdrawal of drinking water;
(c) The local geology and
hydrology;
(d) The operating
pressures and whether a negative pressure gradient is being
maintained;
(e) The nature and
volume of the injected fluid, the formation water, and the process by-products;
and
(f) The injection well
density.
(3) Monitoring
requirements shall, at a minimum, specify:
(a)
Monitoring of the nature of injected fluids with sufficient frequency to yield
representative data on its characteristics;
(b) Monitoring of injection pressure and
either flow rate or volume semi-monthly, or metering and daily recording of
injected and produced fluid volumes as appropriate;
(c) Demonstration of mechanical integrity at
least once every five years during the life of the well;
(d) Monitoring of the fluid level in the
injection zone semi-monthly, where appropriate and monitoring of the parameters
chosen to measure water quality in the monitoring wells semi-monthly;
and,
(e) All Class III wells may be
monitored on a field or project basis rather than an individual well basis by
manifold monitoring. Manifold monitoring may be used in cases of facilities
consisting of more than one injection well, operating with a common manifold.
Separate monitoring systems for each well are not required provided the
owner/operator demonstrates that manifold monitoring is comparable to
individual well monitoring.
H. Reporting Requirements for Class II Wells.
(1) Reporting requirements include a
quarterly report to the Department summarizing the results of monitoring
required. Such summary shall include monthly records of injected fluids, and
any major changes in characteristics or sources of injected fluid. Previously
submitted information may be included by reference.
(2) Owners or operators of hydrocarbon
storage and enhanced recovery projects may report on a field or project basis
rather than an individual well basis where manifold monitoring is
used.
I. Reporting
Requirements for Class III and Class V.A. Wells. Reporting requirements
include:
(1) Quarterly reporting to the
Department on required monitoring;
(2) Results of mechanical integrity and any
other periodic test required by the Department reported with the first regular
quarterly report after the completion of the test; and
(3) Monitoring may be reported on a project
or field basis rather than individual well basis where manifold monitoring is
used.