R655-1-6. Abandonment and Sealing

  6.1 Objectives: The objectives of abandonment are to block interzonal migration of fluids so as to:

  (a) Prevent contamination of fresh waters or other natural resources.

  (b) Prevent damage to geothermal reservoirs.

  (c) Prevent loss of reservoir energy.

  (d) Protect life, health, environment and property.

  6.2 General Requirements: The following are general requirements which are subject to review and modification for individual wells or field conditions:

  (a) A notice of intent to abandon geothermal resource wells is required to be filed with the Division five days prior to beginning abandonment procedures. A permit to abandon may be given orally by the State Engineer provided the operator submits a written request for abandonment within 24 hours of the oral request.

  (b) A history of geothermal resource wells shall be filed within sixty days after completion of abandonment procedures.

  (c) All wells abandoned shall be monumented and the description of the monument shall be included in the history of well report. Monument shall consist of a four-inch diameter pipe 10 feet in length of which four feet shall be above ground. The remainder shall be imbedded in concrete. The applicant's name, application number, and location of the well shall be shown on the monument. An abandoned well on tilled land shall be marked in a manner approved by the State Engineer.

  (d) Good quality, heavy drilling fluid shall be used to replace any water in the hole and to fill all portions of the hole not plugged with grout.

  (e) All grout plugs with a possible exception of the surface plug shall be pumped into the hole through drill pipe or tubing.

  (f) All open annuli shall be filled solid with grout to the surface.

  (g) A minimum of 100 feet of grout shall be emplaced straddling the interface or transition zone at the base of ground water aquifers.

  (h) One hundred feet of grout shall straddle the placement of the shoe plug on all casings including conductor pipe.

  (i) A surface plug of either neat cement or concrete mix shall be in place from the top of the casing to at least 50 feet below the top of the casing.

  (j) All casing shall be cut off at least five feet below land surface.

  (k) Grout plugs shall extend at least 50 feet over the top of any liner installed in the well.

  (l) Injection wells are required to be abandoned in the same manner as other wells.

  (m) Other abandonment procedures may be approved by the Division if the owner or operator can demonstrate that the geothermal resource, ground waters, and other natural resources will be protected. Approval must be given in writing prior to the beginning of any abandonment procedures.

  (n) Within five days after the completion of the abandonment of any well or injection well, the owner or operator of the abandoned well or injection well shall report in writing to the Division on all work done with respect to the abandonment.