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RULE §331.244Bedded Salt Cavern Construction Standards

(a) Plans and specifications. Except as specifically required in the terms of the disposal well permit, construction of the cavern shall be done in accordance with all permit application plans and specifications. Any proposed changes to the plans and specifications must be certified in writing by the executive director that said changes provide protection standards equivalent to or greater than the original design criteria.

(b) Standards for bedded salt cavern construction.

  (1) The creation of waste disposal caverns within bedded salt shall be accomplished by the controlled dissolution of the sidewalls of the well bore to a specified maximum diameter, between selected elevations specified in the permit as the top and bottom of the injection interval.

  (2) The enlargement of a portion of the original well bore to serve as the cavern shall be done according to the cavern construction plans which shall be submitted as a part of the permit application. The cavern construction plans shall demonstrate at a minimum, the following:

    (A) adjacent caverns shall be separated by a minimum pillar to cavern diameter ratio of 2.0 to ensure a sufficient amount of separation for cavern safety and stability;

    (B) that cavern dimensions have been designed by a qualified professional engineer and geologist, to ensure the structural integrity of the cavern;

    (C) if an applicant proposes to conduct solution-mining activities concurrent with waste disposal, a plan for the controlled expansion of the cavern;

    (D) plans for continual monitoring of the volumes of materials injected and produced during cavern development and waste injection;

    (E) plans for cavern pressure tests and sonar surveys to determine the cavern dimensions, volume, geometric shape, and characterization of anomalies;

    (F) the cavern construction process shall be conducted under the supervision of a qualified professional engineer, with current registration under the Texas Engineering Practice Act, in accordance with accepted practices in the cavern construction industry; and

    (G) all brines displaced from the cavern shall be managed and/or disposed of in facilities authorized for such purpose.

(c) Injection tubing. Except for circulation of drilling fluids during well construction, all injection activities for bedded salt cavern construction and waste disposal in a bedded salt cavern shall be performed through removable injection tubing(s) installed inside the cemented long string casing and extending from the wellhead at ground surface to the bedded salt cavern below the long string casing seat.

(d) Logs and Tests.

  (1) The permit applicant shall submit, as part of its construction plan, information identifying the tests which it will use to verify cavern dimensions. This information shall include at a minimum, the following:

    (A) a description of surveys, logs, and tests to be run and analyzed, including any quantitative performance standards appropriate for any such procedure; and

    (B) the frequency of such surveys or logs.

  (2) Before waste disposal, the integrity of the cavern shall be tested in accordance with §331.43(b) of this title (relating to Mechanical Integrity Standards).

(e) Workovers.

  (1) The permittee shall notify the executive director before commencing any workover operation or corrective maintenance which involves taking the disposal well out of service. The notification shall be in writing and shall include plans for the proposed work. The executive director may grant an exception of the prior written notification when immediate action is required. Approval by the executive director shall be obtained before the permittee may begin any workover operation or corrective maintenance that involves taking the well out of service. Pressure control equipment shall be installed and maintained during workovers which involve the removal of tubing.

  (2) Well mechanical integrity shall be demonstrated following any major operations which involve removal of the injection tubing, recompletions, or unseating of the packer. Cavern integrity demonstration may be required by the executive director in instances where the integrity of the casing seat or cavern may be compromised.

(f) Reports and approval.

  (1) Initial cavern integrity report. The operator shall submit a report with the results of all tests regarding cavern integrity, within 30 days of completion of the bedded salt cavern construction stage.

  (2) Notification of completion of the cavern construction stage. Within 90 days of completion of cavern construction, the permittee shall provide notification to the executive director which states that the cavern construction is in compliance with the applicable provisions of the permit. The permittee shall submit to the executive director the following reports and certifications prepared and sealed by a professional engineer with current registration under the Texas Engineering Practice Act:

    (A) final construction, "as-built" plans and specifications, injection and confining zone data, and an evaluation of the considerations under §331.45(3) of this title (relating to Executive Director Approval of Construction and Completion);

    (B) certification that the construction of the cavern has been completed in accordance with the provisions of the disposal well permit and with the design and construction specifications of the permittee's application;

    (C) certification that actual confining and injection zone data obtained will not result in need for a change in the operating parameters specified in the permit; and

    (D) certification that the bedded salt cavern injection zone will not be in or above a formation which within 1/4 mile of the bedded salt cavern injection zone contains an underground source of drinking water.

Source Note: The provisions of this §331.244 adopted to be effective August 16, 2012, 37 TexReg 6078

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