(a) It shall be the duty of any Owner, Operator, or person who assumes ownership, or contractor, drilling any well, seismic, stratigraphic test, core, or other exploratory hole, whether cased or uncased, regardless of diameter, to plug said hole in accordance with the requirements of the Supervisor or as set forth hereinafter and in a manner sufficient to properly protect all fresh water bearing formations and possible or probable oil or gas bearing formations.
(b) For wells as defined in Chapter 1, Section 2(hhh) of these Rules and Regulations, and all stratigraphic test wells being abandoned, plugging must be accomplished by the following: - (i) All cement and additives shall consist of API class cement and additives, unless use of non-API cement and additives has prior approval from the Supervisor.
- (ii) Wells without production casing must be plugged by placing cement plugs of at least one hundred foot (100') length consisting of approved cement and additives, mixed at a density approved by the Supervisor or his Authorized Agent over the following:
- (A) Open hole porous and permeable formations;
- (B) At least every two thousand five hundred feet (2,500') if porous and permeable formations are not encountered;
- (C) In the base of the surface casing and at least one hundred feet (100') inside the casing at the surface. If multiple casing strings are present, a minimum one hundred foot (100') plug will be placed in the annulus between each casing string at the outside casing shoe and a minimum one hundred foot (100') plug in each annulus at the surface;
- (D) At any other depth as required by the Supervisor;
- (E) The spacer between all cement plugs must be a fluid consistent with that which was used to drill the well or as approved by the Supervisor.
- (iii) Wells with production casing must be plugged by placing cement plugs of at least one hundred foot (100') length consisting of approved cement and additives, mixed at a density approved by the Supervisor or his Authorized Agent at least every two thousand five hundred feet (2,500'), in the base of the surface casing, and at least one hundred feet (100') inside the casing at the surface. If multiple casing strings are present, a minimum one hundred foot (100') plug must be placed in the annulus between each casing string at the outside casing shoe, and a minimum one hundred foot (100') plug in each annulus at the surface.
- (A) Prior to commencing plugging operations, all produced fluids must be circulated from the well using fresh water or other fluid as required to maintain an overbalance of the producing formation.
- (B) All perforations must be isolated by squeeze cementing utilizing a mechanical cement retainer set no more than fifty feet (50') above the uppermost perforation, or by a method approved by the Supervisor. The volume of cement will be no less than the volume between the retainer and the deepest perforation plus fifty percent (50%) excess. A minimum one hundred foot (100') plug must also be placed on top of the cement retainer. If access to the perforated areas of the wellbore has been lost, alternative procedures may be proposed by the Owner/Operator. The Supervisor shall determine or approve which method and the quantity of cement that shall be used or the alternative method of plugging, if access to perforations is lost;
- (C) The Owner/Operator may leave the production casing in place, provided that the Owner/Operator demonstrates that the casing exhibits mechanical integrity in a manner prescribed or approved by the Supervisor. If casing fails a mechanical integrity test, the casing leaks must be isolated and squeeze cemented utilizing a mechanical cement retainer, or by a method approved by the Supervisor.
- (D) If it is determined that any formation containing fresh water and potable water, as defined under Chapter 1, Section 2(s) of these Rules and Regulations, was not sealed or separated when production casing was cemented, the casing must be perforated at the base of the fresh water and potable water zone and squeeze cemented utilizing a mechanical cement retainer, or by a method approved by the Supervisor, with a volume of cement sufficient to cover the formation. The Supervisor may also require the production casing to be perforated at a depth of the shoe of the surface casing and that cement be squeezed or circulated through the perforations through the uncemented zone; and,
- (E) If an attempt is made to recover production casing after the retrievable part of the production casing has been removed, cement must be circulated to fill at least a one hundred foot (100') interval of which fifty feet (50') must be inside the casing stub. The remainder of the hole shall be plugged in the manner prescribed under subsection (b)(i) of this section.
- (iv) Powder River Basin Coalbed Methane Wells.
- (A) The minimum density requirement for cement slurry shall be 13.5 pounds per gallon (ppg) with no less than twenty-five percent (25%) of cement by weight with a yield not greater than 1.29 cubic feet per sack. The Supervisor may approve alternate cement blends submitted by the Operator.
- (B) Each completed section of the well shall be isolated by filling the underreamed or perforated section of the hole with bentonite hole plug extending a minimum of twenty feet (20') above the completed section, or isolating the underreamed or perforated section with a mechanical bridge plug set no higher than thirty feet (30') above the underreamed or perforated section. The Supervisor may approve other material for the openhole portion in lieu of the bentonite hole plug.
- (C) The bentonite plugs and/or mechanical bridge plugs shall be topped with a one hundred foot (100') cement plug, and one hundred foot (100') plugs will also be set every seven hundred fifty feet (750') along with a one hundred foot (100') plug at the surface.
(c) In plugging horizontal wells, a continuous cement plug shall be placed from at least one hundred feet (100') into the lateral back to one hundred feet (100') into the vertical portion of the wellbore, unless an alternate plugging program is approved by the Supervisor. The remaining portion of the vertical wellbore shall then be plugged in accordance with the preceding requirements.
(d) No substance of any nature or description other than those normally used in plugging operations shall be placed in any well at any time during plugging operations.
(e) Verbal approval to plug and abandon or approval of a Notice of Intent to Abandon (Form 4) must be obtained prior to commencing actual plugging operations. Under Chapter 4, Section 11 of these rules, special plugging orders or variances from normal practice may be obtained or set forth when conditions dictate to protect fresh water bearing formations.
(f) When the well has been plugged, a notarized Subsequent Report of Abandonment (Form 4) accompanied by a job log or cement verification report from the plugging contractor specifying the type of fluid used to fill the wellbore, type of slurry volume of API Class cement used, date of work, and depth of plugs placed must be submitted to the Supervisor. Copies of plugging reports or other pertinent information for wells drilled on federal lands must be filed with the Commission in a timely manner in order that field information for UIC area reviews is current.
(g) In addition to the requirements under subsection (b) of this section, all wells within the Special Sodium Drilling Area - A, as defined in Chapter 1, Section 2(tt), shall have a directional survey run from the base of the Trona Interval to surface if not previously run. A cement bond log or other appropriate log shall be run from the base of the Trona Interval to top of cement to determine the integrity of the cement in casing annuluses.
(h) In addition to the requirements under subsection (b) of this section, all wells in the SSDA - A or - B shall be plugged by placing a continuous cement plug, at a minimum, through the Trona Interval in all open zones, open casing zones, and all open or inadequately cemented casing annuluses. Perforation and squeeze cementing shall be used where required by the Supervisor.
055-3 Wyo. Code R. § 3-18