(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(lll) 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(t) 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(ww), 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.
