Current through Register Vol. 50, No. 9, September 20, 2024
A.
Applicability. This Section applies to all applicants, owners or operators of
solution-mining wells. The applicant, owner or operator shall be responsible
for showing that the solution-mining operation shall be accomplished using good
engineering and geologic practices for solution-mining operations to preserve
the integrity of the salt stock and overlying sediments. In addition to all
applicants showing this in their application, as part of the compliance review
found in subsection 3309 K,
the commissioner may require any owner or operator of a solution-mining well to
provide the same or similar information required in this Section. This shall
include, but not be limited to:
1. an
assessment of the engineering, geological, geomechanical, geochemical, and
geophysical properties of the salt stock;
2. stability of the salt stock and overlying
and surrounding sediments;
3.
stability of the cavern design (particularly regarding its size, shape, depth,
and operating parameters);
4. the
amount of separation between the cavern of interest and adjacent caverns and
structures within the salt stock;
5. the amount of separation between the
outermost cavern wall and the periphery of the salt stock; and
6. an assessment of well information and oil
and gas activity within the vicinity of the salt dome which may affect the
solution-mining cavern.
B. Geological Studies and Evaluations. The
applicant, owner, or operator shall do a thorough geological, geophysical,
geomechanical, and geochemical evaluation of the salt stock to determine its
suitability for solution-mining, stability of the cavern under the proposed set
of operating conditions, and where applicable, the structural integrity of the
salt stock between an adjacent cavern and salt periphery under the proposed set
of operating conditions. A listing of data or information used to characterize
the structure and geometry of the salt stock shall be included.
1. Where applicable, the geologic evaluation
shall include, but should not be limited to:
a. geologic mapping of the structure of the
salt stock and any cap rock;
b.
geologic history of salt movement;
c. an assessment of the impact of possible
anomalous zones (salt spines, shear planes, etc.) on the solution-mining well
or cavern;
d. deformation of the
cap rock and strata overlying the salt stock;
e. investigation of the upper salt surface
and adjacent areas involved with salt dissolution;
f. cap rock formation and any non-vertical
salt movement.
2. The
applicant shall perform a thorough hydrogeological study on strata overlying
the salt stock to determine the occurrence of the lowermost underground source
of drinking water immediately above and in the vicinity of the salt
stock.
3. The applicant shall
investigate regional tectonic activity and the potential impact (including
ground subsidence) of the project on surface and subsurface
resources.
4. The proximity of all
existing and proposed solution-mining caverns to the periphery of the salt
stock and to manmade structures within the salt stock shall be demonstrated to
the Office of Conservation at least once every five years (see
§3309.K) by providing
the following:
a. an updated structure contour
map of the salt stock. The updated map should make use of all available data.
The horizontal configuration of the salt caverns should be shown on the
structure map and reflect the caverns' maximum lateral extent as determined by
the most recent sonar caliper surveys; and
b. vertical cross-sections of the salt
caverns showing their outline and position within the salt stock...
Cross-sections should be oriented to indicate the closest approach of the salt
cavern wall to the periphery of the salt stock. The outline of the salt cavern
should be based on the most recent sonar caliper survey.
C. Core Sampling
1. Unless specifically exempted by the
commissioner, at least one well at the site of the solution-mining well (or the
salt dome) shall be or shall have been cored over sufficient depth intervals to
yield representative samples of the subsurface geologic environment. This shall
include coring of the salt stock and may include coring of overlying
formations, including any cap rock. Cores should be obtained using the whole
core method. Core acquisition, core handling, and core preservation shall be
done according to standard field sampling practices considered acceptable for
laboratory tests of recovered cores.
2. Repealed.
D. Core Analyses and Laboratory Tests.
Analyses and tests shall consider the characteristics of the injected materials
and should provide data on the salt's geomechanical, geophysical, geochemical,
mineralogical properties, x-ray diffraction, microstructure, and where
necessary, potential for adjacent cavern connectivity, with emphasis on cavern
shape and the operating conditions. All laboratory tests, experimentation, and
numeric modeling shall be conducted using methods that simulate the proposed
operating conditions of the cavern. Test methods shall be selected to define
the deformation and strength properties and characteristics of the salt stock
under cavern operating conditions. Test results, analyses, and operating
recommendations shall be summarized in an interpretive report.
E. Area of Review. A thorough evaluation
shall be undertaken of both surface and subsurface activities in the defined
area of review of the individual solution-mining well or project area (area
permit) that may influence the integrity of the salt stock, solution-mining
well, and cavern, or contribute to the movement of injected fluids outside the
cavern, wellbore, or salt stock.
1. Surface
Delineation
a. The area of review for an
individual solution-mining well shall be a fixed radius around the wellbore of
not less than 1320 feet.
b. The
area of review for wells in a solution-mining project area (area permit), shall
be the project area plus a circumscribing area the width of which is not less
than 1320 feet. The area of review for new solution-mining wells within an
existing area permit shall be a circumscribing area around the proposed
solution-mining well the width of which is not less than 1320 feet. Only
information outlined in
§3313. E 2, not
previously assessed as part of the area permit application review or as part of
the review of an application for a subsequent solution-mining well located
within the area permit, shall be considered.
c. Exception shall be noted as shown in
§3313. E.2.c and d
below.
2. Subsurface
Delineation. At a minimum, the following shall be identified within the area of
review:
a. all known active, inactive, and
abandoned wells within the area of review with known depth of penetration into
the cap rock or salt stock;
b. all
known water wells within the area of review;
c. all caverns within the salt stock
regardless of usage, depth of penetration, or distance to the proposed
solution-mining well or cavern;
d.
all conventional (dry or room and pillar) mining activity either active or
abandoned occurring anywhere within the salt stock regardless of distance to
the proposed solution-mining well or cavern.
e. all producing formations either active or
depleted.
3. Water
Samples. A representative number of water wells identified under
§3313.E.2.b shall be
sampled and analyzed by an accredited laboratory for chloride and total
dissolved solids.
F.
Corrective Action
1. For manmade structures
in the area of review that penetrate the salt stock and are not properly
constructed, completed, or plugged and abandoned, the applicant shall submit a
corrective action plan consisting of such steps, procedures, or modifications
as are necessary to prevent the movement of fluids outside the cavern or into
underground sources of drinking water.
a.
Where the plan is adequate, the provisions of the corrective action plan shall
be incorporated into the permit as a condition.
b. Where the plan is inadequate, the Office
of Conservation shall require the applicant to revise the plan, or prescribe a
plan for corrective action as a condition of the permit, or the application
shall be denied.
2. Any
permit issued for an existing solution-mining well for which corrective action
is required shall include a schedule of compliance for complete fulfillment of
the approved corrective action procedures as soon as possible. If the required
corrective action is not completed as prescribed in the schedule of compliance,
the permit shall be suspended, modified, revoked and possibly reissued, or
terminated according to these rules and regulations.
3. No permit to inject shall be issued for a
new solution-mining well until all required corrective action obligations have
been fulfilled.
4. The commissioner
may require as a permit condition that injection pressure be so limited that
pressure in the injection zone does not cause the movement of fluids into a
underground source of drinking water through any improperly completed or
abandoned well within the area of review. This pressure limitation shall
satisfy the corrective action requirement. Alternatively, such injection
pressure limitation can be part of a compliance schedule and last until all
other corrective action has been taken.
5. When setting corrective action
requirements for solution-mining wells, the commissioner shall consider the
overall effect of the project on the hydraulic gradient in potentially affected
underground sources of drinking water, and the corresponding changes in
potentiometric surface(s) and flow direction(s) rather than the discrete effect
of each well. If a decision is made that corrective action is not necessary,
the monitoring program required in
§3323 shall be designed to verify the
validity of such determination.
6.
In determining the adequacy of proposed corrective action and in determining
the additional steps needed to prevent fluid movement into underground sources
of drinking water, the following criteria and factors shall be considered by
the commissioner:
a. nature and volume of
injection fluid;
b. nature of
native fluids or by-products of injection;
c. potentially affected population;
d. geology;
e. hydrology;
f. history of the injection
operation;
g. completion and
plugging records;
h. abandonment
procedures in effect at the time the well was abandoned; and
i. hydraulic connections with underground
sources of drinking water.
7. The Office of Conservation may prescribe
additional requirements for corrective action beyond those submitted by the
applicant.
AUTHORITY
NOTE: Promulgated in accordance with
R.S.
30:4 et seq.
