Current through Register Vol. 50, No. 9, September 20, 2024
A. General Requirements
1. All materials and equipment used in the
construction of the solution-mining well and related appurtenances shall be
designed and manufactured to 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, hole size, anticipated
ranges and extremes of operating conditions, subsurface temperatures and
pressures, type and grade of cement, and projected life of the solution-mining
well.
2. All solution-mining 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.
a. Where injection is
into a formation which contains water with less than 10,000 mg/l TDS,
monitoring wells shall be completed into the injection zone and into any
underground sources of drinking water above the injection zone which could be
affected by the mining operation. These wells shall be located in such a
fashion as to detect any excursion of injected fluids, process by-products, or
formation fluids outside the mining 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.
b. Where injection is into a formation which
does not contain water with less than 10,000 mg/l TDS, no monitoring wells are
necessary in the injection stratum.
c. Where the injection 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.
d. In determining the number, location,
construction and frequency of monitoring of the monitoring wells the following
criteria shall be considered:
i. the
population relying on the USDW affected or potentially affected by the
injection operation;
ii. the
proximity of the injection 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 injection well
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 done on
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. The commissioner may require additional gyroscopic surveys as
necessary.
3. Caliper logging to
determine borehole size for cement volume calculations shall be done 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, the wellbore of the solution-mining 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
postclosure.
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 pre-operating
requirements of §3325
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 to the injection 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, and
construction material);
e.
corrosiveness of injected fluids and formation fluids;
f. lithology of subsurface formations
penetrated; and
g. type and grade
of cement.
3. Surface
casing shall be set to a depth below the base of the lowermost underground
source of drinking water and shall be cemented to ground surface.
4. All solution-mining 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 shall not be considered one of the two casings.
5. The intermediate casing string shall be
set a minimum of 50 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 and that are being used for solution-mining. 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 set no more than 50 feet
above the deepest casing shoe and 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. The intermediate and final casings shall
be cemented from their respective casing seats to the surface when
practicable.
8. An owner or
operator may propose for approval by the Commissioner of Conservation an
alternative casing program for a new solution-mining well pursuant to an
exception or variance request in accordance with the requirements of
§3303 F
D. Casing and Casing Seat Tests. When
performing tests under this paragraph, 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
1 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 strings set within 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 1
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.
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 1 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 logs, tests, or surveys 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 solution-mining well and other subsurface zones 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. Without exception or
variance to these rules and regulations, all active solution-mining wells shall
be completed with at least two hanging strings except as provided for dual-bore
mining. One hanging string shall be for injection; the second hanging string
shall be for displacing fluid out of the cavern from below the blanket
material. The commissioner may approve a request for a single hanging string in
active solution-mining wells only in the case of dual-bore mining. All inactive
solution-mining wells shall be completed with at least one hanging string
unless excepted by the commissioner. Hanging strings shall be designed with a
collapse, burst, and tensile strength rating conforming to all expected
operating conditions. The design shall also consider the physical and chemical
characteristics of fluids placed into and/or withdrawn from the
cavern.
G. Wellhead Components and
Related Connections. All wellhead components, valves, flanges, fittings,
flowlines, and related connections shall be manufactured of steel. 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/or withdrawn from the cavern under
the specific range of operating conditions, including flow induced vibrations.
The fluid withdrawal side of the wellhead (if applicable) shall be rated for
the same pressure as the water injection side. All components and related
connections shall be maintained in good working order and shall be periodically
inspected by the operator.
AUTHORITY
NOTE: Promulgated in accordance with
R.S.
30:4 et seq.