La. Admin. Code tit. 43 § XVII-3317

Current through Register Vol. 50, No. 11, November 20, 2024

Section XVII-3317 - Well Construction and Completion

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.

La. Admin. Code tit. 43, § XVII-3317

Promulgated by the Department of Natural Resources, Office of Conservation, LR 40:333 (February 2014), Amended LR 42417 (3/1/2016), Amended LR 482310 (9/1/2022).

AUTHORITY NOTE: Promulgated in accordance with R.S. 30:4 et seq.