Current through Register Vol. 50, No. 9, September 20, 2024
A. General Requirements
1. All materials and equipment used in the
construction of the salt cavern 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, physical and behavioral
characteristics of the injected and disposed material under the specific range
of operating conditions, subsurface temperatures and pressures, type and grade
of cement, and projected life of the salt cavern well.
2. All salt cavern wells and salt caverns
shall be designed, constructed, completed, and operated to prevent the escape
of injected or disposed materials out of the salt stock, into an underground
source 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.
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 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.
2. Gyroscopic multi-shot
surveys of the borehole shall be taken at intervals not to exceed every 100
feet of drilled borehole.
3. Where
practicable, caliper logging to determine borehole size for cement volume
calculations shall be done before running casings.
C. Casing and Cementing. Except as specified
below, the wellbore of the salt cavern shall be cased, completed, and cemented
according to rules and regulations of the Office of Conservation and good
petroleum industry engineering practices for wells of comparable depth that are
applicable to the same locality of the salt cavern. Design considerations for
casings and cementing materials and methods shall address the nature and
characteristics of the subsurface environment, the nature of injected and
disposed 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 pre-operating
requirements of §3127
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 or disposed material into zones of porosity or
transmissive permeability in the overburden along the wellbore and to protect
underground sources of drinking water.
2. Surface casing shall be set to a depth
into a confining bed below the base of the lowermost underground source of
drinking water. Surface casing shall be cemented to surface where
practicable.
3. All salt cavern
wells shall be cased with a minimum of two casings cemented into the salt. The
surface casing shall not be considered one of the two casings of this
Subparagraph.
4. New wells drilled
into an existing salt cavern shall have an intermediate casing and a final
cemented casing set 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.
5.
The following applies to wells existing in salt caverns before the effective
date of these rules and regulations and are being converted to salt cavern
waste disposal. 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.
6. The
intermediate and final casings shall be cemented from their respective casing
seats to the surface when practicable.
D. Casing and Casing Seat Tests. When doing
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 shall be
hydrostatically pressure tested to verify casing integrity and the absence of
leaks. For surface casing, the stabilized test pressure applied at the surface
shall be a minimum of 500 pounds per square inch gauge (PSIG). The stabilized
test pressure applied at the surface for all other casings shall be a minimum
of 1,000 PSIG. All casing test pressures shall be maintained for one hour after
stabilization. Allowable pressure loss is limited to five percent of the test
pressure over the stabilized test duration.
2. Casing Seat. The casing seat and cement of
intermediate and production casings shall each be hydrostatically pressure
tested after drilling out the casing shoe. At least 10 feet of formation below
the respective casing shoes shall be drilled before the test. The test pressure
applied at the surface shall be the greater of 1,000 PSIG or 125 percent of the
maximum predicted salt cavern operating pressure. The appropriate test pressure
shall 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.
3. Casing or casing
seat test pressures shall never exceed a pressure gradient equivalent to 0.80
PSI per foot 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) and a temperature log
shall be run on all casings. The Office of Conservation may consider requests
for allowances for wireline logging in large diameter casings or justifiable
special conditions.
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 salt cavern well and other subsurface zones cannot be
demonstrated.
2. A casing
inspection log (or similar log) shall be run on the final cemented
casing.
F. Hanging
Strings. Without exception or variance to these rules and regulations, all salt
cavern wells shall be completed with at least two hanging strings. One hanging
string shall be for waste injection; the second hanging string shall be for
displacing fluid out of the salt cavern from below the blanket material.
Hanging strings shall be designed with a collapse, burst, and tensile strength
rating conforming to all expected operating conditions, including flow induced
vibrations. The design shall also consider the physical and chemical
characteristics of fluids placed into and/or withdrawn from the salt
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 salt 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 waste 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.
