Current through Register Vol. 50, No. 9, September 20, 2024
A. General Requirements
1. All materials and equipment used in the
construction of the Class V storage well and related appurtenances shall be
designed and manufactured for compatibility with the stored material and shall
meet or exceed the operating requirements of the specific project.
Consideration shall be given to depth and lithology of all subsurface geologic
zones, corrosiveness of formation fluids, corrosiveness of the stored material,
compatibility of downhole construction materials, compatibility of wellhead
components, hole size, anticipated ranges and extremes of operating conditions,
subsurface temperatures and pressures, type and grade of cement, and the
projected life of the storage well, etc.
2. All storage wells and caverns shall be
designed, constructed, completed, and operated to prevent the escape of
injected materials out of the salt stock, into or between underground sources
of drinking water, or otherwise create or cause pollution or endanger the
environment or public safety. All phases of design, construction, completion,
and testing shall be prepared and supervised by qualified personnel.
3. Where the storage well penetrates an
underground source of drinking water in an area subject to subsidence or
catastrophic collapse, an adequate number of monitoring wells shall be
completed into the USDW to detect any movement of injected fluids, process
by-products or formation fluids into the USDW. The monitoring wells shall be
located outside the physical influence of the subsidence or catastrophic
collapse.
a. The following criteria shall be
considered in determining the number, location, construction, and frequency of
monitoring of any monitor wells:
i. the
population relying on the USDW affected or potentially affected by the
injection operation;
ii. the
proximity of the storage operation to points of withdrawal of drinking
water;
iii. the local geology and
hydrology;
iv. the operating
pressures and whether a negative pressure gradient is being
maintained;
v. the nature and
volume of the injected fluid, the formation water, and the process by-products;
and
vi. the injected fluid
density.
B. Open Borehole Surveys
1. Open hole wireline surveys that delineate
subsurface lithologies, formation tops (including top of cap rock and salt),
formation fluids, formation porosity, and fluid resistivities shall be
performed on all new wells from total well depth to either ground surface or
base of conductor pipe. Wireline surveys shall include, at a minimum, density,
neutron, sonic, and caliper logs and shall be presented with gamma-ray and,
where applicable, spontaneous potential curves. All surveys shall be presented
on a scale of 1 inch to 100 feet and a scale of 5 inches to 100 feet and all
logs must include the depth datum. A descriptive report interpreting the
results of such logs and tests shall be prepared and submitted to the
commissioner.
2. Gyroscopic
multi-shot surveys of the borehole shall be taken at intervals not to exceed
every 100 feet of drilled borehole.
3. Caliper logging to determine borehole size
for cement volume calculations shall be performed before running
casings.
4. The owner or operator
shall submit all wireline surveys as one paper copy and an electronic version
in a format approved by the commissioner.
C. Casing and Cementing. Except as specified
below, and inclusive of the additional requirements which may be found in
§3739, the wellbore of the storage well shall be cased, completed, and cemented
according to rules and regulations of the Office of Conservation and good
industry engineering practices for wells of comparable depth that are
applicable to the same locality of the cavern. Design considerations for
casings and cementing materials and methods shall address the nature and
characteristics of the subsurface environment, the nature of injected
materials, the range of conditions under which the well, cavern, and facility
shall be operated, and the expected life of the well including closure and
post-closure.
1. Cementing shall be by the
pump-and-plug method or another method approved by the Office of Conservation
and shall be circulated to the surface. Circulation of cement may be done by
staging.
a. For purposes of these rules and
regulations, circulated (cemented) to the surface shall mean that actual cement
returns to the surface were observed during the primary cementing operation. A
copy of the cementing company's job summary or cementing ticket indicating
returns to the surface shall be submitted as part of the preoperating
requirements of §3725
b. If returns
are lost during cementing, the owner or operator shall have the burden of
showing that sufficient cement isolation is present to prevent the upward
movement of injected material into zones of porosity or transmissive
permeability in the overburden along the wellbore and to protect underground
sources of drinking water.
2. In determining and specifying casing and
cementing requirements, the following factors shall be considered:
a. depth of the storage zone;
b. injection pressure, external pressure,
internal pressure, axial loading, etc.;
c. borehole size;
d. size and grade of all casing strings (wall
thickness, diameter, nominal weight, length, joint specification, construction
material, etc.);
e. corrosiveness
of injected fluids and formation fluids;
f. lithology of subsurface formations
penetrated;
g. type and grade of
cement.
3. Surface casing
shall be set to a depth into a confining bed below the base of the lowermost
underground source of drinking water and shall be cemented to ground
surface.
4. At a minimum, all Class
V storage wells shall be cased with a minimum of two casings cemented into the
salt. One casing string shall be an intermediate string, the other being the
final cemented string. The surface casing will not be considered one of the two
casings extending into the salt.
a. All
cemented casings in contact with the injected substances shall be constructed
of compatible materials with sufficient strength and collapse
resistance.
5. The
intermediate cemented casing shall be set at a minimum of 100 feet into the
salt. The final cemented casing shall be set a minimum distance of 300 feet
into the salt and shall make use of a sufficient number of casing
centralizers.
6. The following
applies to wells existing in caverns before the effective date of these rules
and regulations. If the design of the well or cavern precludes having distinct
intermediate and final casing seats cemented into the salt, the wellbore shall
be cased with two concentric casings run from the surface of the well to a
minimum distance of 300 feet into the salt. The inner casing shall be cemented
from its base to surface. Alternatively, a packer and tubing completion may be
substituted for the inner casing string. The packer shall be considered the
effective casing seat and must be set a minimum distance of 300 feet into the
salt and within 50 feet of the deepest cemented casing seat.
7. All cemented casings shall be cemented
from their respective casing seats to the surface when practicable; however, in
every case, casings shall be cemented a sufficient distance to prevent
migration of the stored products into zones of porosity or permeability in the
overburden.
D. Casing and
Casing Seat Tests. When performing tests under this subsection, the owner or
operator shall monitor and record the tests by use of a surface readout
pressure gauge and a chart or a digital recorder. All instruments shall be
properly calibrated and in good working order. If there is a failure of the
required tests, the owner or operator shall take necessary corrective action to
obtain a passing test.
1. Casing. After
cementing each casing, but before drilling out the respective casing shoe, all
casings will be hydrostatically pressure tested to verify casing integrity and
the absence of leaks. The stabilized test pressure applied at the well surface
will be calculated such that the pressure gradient at the depth of the
respective casing shoe will not be less than 0.7 PSI/FT of vertical depth or
greater than 0.9 PSI/FT of vertical depth. All casing test pressures will be
maintained for one-hour after stabilization. Allowable pressure loss is limited
to 5 percent of the test pressure over the stabilized test duration. Test
results will be reported as part of the pre-operating requirements.
2. Casing Seat. The casing seat and cement of
the intermediate and production casings will each be hydrostatically pressure
tested after drilling out the casing shoe. At least 10 feet of formation below
the respective casing shoes will be drilled before the test.
a. For all casings below the surface casing,
excluding the casing string(s) set into the salt, the stabilized test pressure
applied at the well surface will be calculated such that the pressure at the
casing shoe will not be less than the 85 percent of the predicted formation
fracture pressure at that depth. The test pressures will be maintained for one
hour after pressure stabilization. Allowable pressure loss is limited to 5
percent of the test pressure over the stabilized test duration. Test results
will be reported as part of the preoperating requirements.
b. For casing strings set within the salt,
the test pressure applied at the surface will be the greater of the maximum
predicted salt cavern operating pressure or a pressure gradient of 0.85 PSI/FT
of vertical depth calculated with respect to the depth of the casing shoe. The
test pressures will be maintained for one hour after pressure stabilization.
Allowable pressure loss is limited to 5 percent of the test pressure over the
stabilized test duration. Test results will be reported as part of the
pre-operating requirements.
3. Casing or casing seat test pressures shall
never exceed a pressure gradient equivalent to 0.90 PSI/FT of vertical depth at
the respective casing seat or exceed the known or calculated fracture gradient
of the appropriate subsurface formation. The test pressure shall never exceed
the rated burst or collapse pressures of the respective casings.
E. Cased Borehole Surveys. A
cement bond with variable density log (or similar cement evaluation tool) shall
be run on all casing strings. When practicable, a temperature log shall be run
on all casing strings. The Office of Conservation may consider requests for
alternative means of compliance for wireline logging in large diameter casings
or justifiable special conditions. A descriptive report interpreting the
results of such logs shall be prepared and submitted to the commissioner.
1. It shall be the duty of the well
applicant, owner or operator to prove adequate cement isolation on all cemented
casings. Remedial cementing shall be done before proceeding with further well
construction, completion, or conversion if adequate cement isolation between
the storage well and subsurface formations cannot be demonstrated.
2. A casing inspection log (or similar
approved log or method of casing evaluation) shall be run on the final cemented
casing.
3. When submitting wireline
surveys, the owner or operator shall submit one paper copy and an electronic
copy in a format approved by the commissioner.
F. Hanging Strings. All Class V storage wells
shall be completed with at least one hanging string unless specifically
exempted by the Commissioner. Hanging strings shall be designed with collapse,
burst, and tensile strength ratings conforming to all expected operating
conditions. The design shall also consider the compatibility of the material
used with the physical and chemical characteristics of fluids placed into and
withdrawn from the cavern.
G.
Wellhead Components and Related Connections. All wellhead components, valves,
flanges, fittings, flowlines, and related connections shall be manufactured of
material compatible with the stored products and any incidental substances. All
components shall be designed with a test pressure rating of at least 125
percent of the maximum pressure that could be exerted at the surface. Selection
and design criteria for components shall consider the physical and chemical
characteristics of fluids placed into and withdrawn from the cavern under the
specific range of operating conditions, including flow induced vibrations. The
fluid withdrawal side of the wellhead shall be rated for the same pressure as
the fluid injection side. All components and related connections shall be
periodically inspected by the well operator and maintained in good working
order.
AUTHORITY
NOTE: Promulgated in accordance with
R.S.
30:4 et seq. and
R.S.
30:23 et seq.
