Alaska Admin. Code tit. 20, § 25.1220 – Logging, sampling, and testing before Class VI well operation

(a) During the drilling and construction of a Class VI well, the storage operator shall run appropriate logs, surveys and tests to determine or verify the depth, thickness, porosity, permeability, and lithology of, and the salinity of any formation fluid in all relevant geologic formations to ensure conformance with the Class VI well construction requirements under 20 AAC 25.1210 and to establish accurate baseline data against which future measurements may be compared. The storage operator shall submit to the commission not more than 90 days after completion, a descriptive report prepared by a knowledgeable log analyst that includes an interpretation of the results of such logs and tests. At a minimum, logs and tests under this section must include:
1. (1) deviation checks during drilling on all holes constructed by drilling a pilot hole which is enlarged by reaming or another method; the checks must be at sufficiently frequent intervals to determine the location of the borehole and to ensure that vertical avenues for fluid movement in the form of diverging holes are not created during drilling; and
2. (2) before and upon installation of the surface casing
  1. (A) resistivity, spontaneous potential, and caliper logs before the casing is installed; and
  2. (B) a cement bond and variable density log to evaluate cement quality radially, and a temperature log after the casing is set and cemented;
3. (3) before and upon installation of the long string casing
  1. (A) resistivity, spontaneous potential, porosity, caliper, gamma ray, fracture finder logs, and any other logs the commission requires for the given geology before the casing is installed; and
  2. (B) a cement bond and variable density log, and a temperature log after the casing is set and cemented;
4. (4) a series of tests designed to demonstrate the internal and external mechanical integrity of injection wells, which may include:
  1. (A) a pressure test with liquid or gas;
  2. (B) a tracer survey such as oxygen-activation logging;
  3. (C) a temperature or noise log;
  4. (D) a casing inspection log; and
5. (5) any alternative methods that provide equivalent or better information than would be provided by the tests in (a)(1) - (4) of this subsection and that are required by or approved by the commission.
(b) The storage operator shall take whole cores or sidewall cores of the injection zone and confining system and formation fluid samples from the injection zone, and shall submit to the commission a detailed report prepared by a log analyst that includes well log analyses, including well logs, core analyses, and formation fluid sample information. The commission may accept information on cores from nearby wells if the storage operator demonstrates that core retrieval is not possible and that such cores are representative of conditions at the well. The commission may require the storage operator to core other formations in the borehole.
(c) The storage operator shall record the fluid temperature, pH, conductivity, reservoir pressure, and static fluid level of the injection zone.
(d) At a minimum, the storage operator shall determine or calculate the following information concerning the injection and confining zone:
1. (1) fracture pressure;
2. (2) other physical and chemical characteristics of the injection and confining zone; and
3. (3) other physical and chemical characteristics of the formation fluid in the injection zone.
(e) To verify hydrogeologic characteristics of the injection zone, the storage operator shall, upon completion of a Class VI well but before operation, conduct a pressure fall-off test and
1. (1) a pump test; or
2. (2) injectivity tests.
(f) The storage operator shall provide the commission with the opportunity to witness all logging and testing required by this section. The storage operator shall submit a schedule of such activities to the commission not less than 30 days before conducting the first test and submit any changes to the schedule not less than 30 days before the next scheduled test.