037-4 Wyo. Code R. §§ 4-4 - Water Well Plugging and Abandonment

(a) When a well is temporarily removed from service, it shall be kept in a state of good repair. The top of the well casing shall be sealed with a secure watertight cap that will prevent tampering and entrance of contaminants, animals, or debris.

(b) The well owner is responsible to ensure that any well (including any test well or replaced well) which is permanently abandoned or removed from service shall be entirely plugged to prevent contamination from the surface or any other source and to remove any further hazard potential that an unused well or abandoned drill hole might pose. All pumps, pipe, wiring, caps, and other obstructions/debris that may interfere with adequate plugging operations shall be removed from the well. Suitable cement-based mixtures or bentonite mixtures shall be used for grouting material. If a well is permitted under DEQ-WQD rules, those rules may be consulted for abandonment procedures. For all other wells, an abandoned well shall be plugged by one of the following methods in accordance with type of well completion and subsurface geologic and /or hydrostatic conditions:

(i) Dug wells or excavations [Type I Wells, see Section 6(a)(1) ] exposing the shallow water table shall be filled to static water level with clean fill such as gravel or sand. The remaining hole is to be filled with bentonite to 2-feet below ground surface. The remaining 2 feet shall be filled with native soil and mounded slightly at the top to allow for settling.

(ii) If possible, casing shall be removed from Type II Wells [See Section 6(a)(ii) ] prior to plugging procedures. Cased or uncased wells in unconsolidated formations shall be destroyed by placement of clean fill, such as gravel or sand, opposite the completed (screened, perforated interval) or water bearing zone and then grouting to the surface. The upper surface portion of the cased well must be cut off a minimum of 18 inches below ground level and the area back-filled with enough clean soil material to allow for settling.

(iii) Type III, gravel pack wells [See Section 6(a) (iii) ] shall be grouted from bottom to top in order to accomplish a complete seal. Grout slurries shall not be poured from the land surface through a column of water. In order to place the grout in wells with water columns, it shall be pumped via tremie pipe by positive displacement or similar method (pressure grouted) from the bottom of the well to a sufficient elevation such that an uninterrupted seal may be emplaced to the land surface. The upper surface portion of the cased well must be cut off a minimum of 18 inches below ground level and the area back-filled with enough clean soil material to allow for settling.

(iv) Plugging of open-hole completed wells [Type IV Wells, see Section 6(a)(iv) ] shall consist of grouting the entire well. Necessary pressure grouting procedures shall be utilized to permanently seal off flow and/or pressure of the artesian aquifer such that surface or subsurface leakage will not occur.

(v) Type V Wells [see Section 6(a)(v) ] shall be decommissioned in the same manner as that prescribed for Type III Wells.

(vi) Type I, II, or III wells may alternately be grouted from bottom to top with bentonite grout to create a complete seal.

(c) If there is any question of proper procedure for extraordinary plugging/abandonment conditions, the State Engineer's Office, Ground Water Division must be consulted for instruction before commencement of plugging activities.

(d) Upon completion of plugging and abandonment of a water well, the well owner shall report the date and method of abandonment to the State Engineer's Office, Ground Water Division with reference to the State Engineer permit number issued for the well and the well location.

Notes

037-4 Wyo. Code R. §§ 4-4