Administrative Rules of Montana › Department 36 - NATURAL RESOURCES AND CONSERVATION › Chapter 36.22 - OIL AND GAS CONSERVATION › Subchapter 36.22.5 - Seismic Exploration Activities › Rule 36.22.502 - PLUGGING AND ABANDONMENT

Current through Register Vol. 13, July 5, 2024
Unless otherwise agreed to between the surface owner; the
				  company, firm, corporation, or individual responsible for the drilling of
				  seismic shot holes; and the board's designated inspector, all such holes shall
				  be plugged and abandoned as set forth below; provided, however, that before the
				  surface owner agrees to a plugging method which deviates from this rule, he
				  must be given a copy of this rule:
(1)
				The seismic company responsible for the plugging and abandonment of seismic
				shot holes shall notify the board in writing at its Billings office of its
				intent to plug and abandon, including the date and time such activities are
				expected to commence, the location by section, township and range of the holes
				to be plugged, and the name and telephone number of the person in charge of the
				plugging operations. A copy of this notice shall be sent to the surface owner
				at the same time.
(2) All seismic
				shot holes shall be plugged before shooting. Exceptions may be granted after
				approval by the board's designated inspector. In the event the original plug
				does not hold, the hole shall be properly plugged as soon as reasonably
				practicable; however, in no event shall any hole remain unplugged for a period
				of more than 30 days unless, upon application, the board or its staff grants an
				extension which may not exceed 90 days. All holes shall be temporarily capped
				during the period between drilling and final plugging.
(3) When drilling seismic shot holes, and
				non-artesian water is encountered or when water is used in conjunction with the
				drilling, plugging shall be accomplished by filling the hole with coarse ground
				bentonite from the bottom up to 5 feet above the static water level with a
				minimum of 100 pounds of bentonite. The hole shall be further filled and tamped
				with cuttings to a depth of three feet below ground level. All shot holes
				drilled in the glacial till area of Montana as shown on USGS Miscellaneous
				Geologic Investigations Map I-327 shall be filled with coarse ground bentonite
				from the bottom to 3 feet below the surface. A commercial plug shall be set at
				this depth with a permit number or the name of the contractor either imprinted
				on the plug or on a plastic or metallic tag securely attached to the plug. The
				remainder of the hole shall be filled with cuttings and soil, and a sufficient
				mound shall be left over the hole to allow for settling.
(a) With the approval of the board's
				designated inspector the shot hole may be plugged by filling the hole with
				bentonite-water slurry by hose injection and displacement upwards from the
				maximum depth attainable. The slurry mixture shall have a marsh funnel
				viscosity of 60 seconds or greater per quart (subject to field verification on
				site) and shall contain a minimum of 28 pounds of commercial plugging bentonite
				per 42 gallons of water. The hole shall be filled to a depth of 3 feet below
				ground level and the commercial plug shall be set at this depth. The remainder
				of the hole shall be filled with cuttings and soil, and a sufficient mound
				shall be left over the hole to allow for settling.
(b) Seismic holes that penetrate artesian
				water deposits shall be stabilized with a cement slurry to a level not higher
				than three feet below the surface of the ground. The cement slurry shall be of
				sufficient density to contain the waters to their native strata. The remainder
				of the hole shall be filled with native surface material. When alkaline or
				saline waters are encountered, the hole shall be plugged immediately as set
				forth in (3) and (a) except, if the bentonite-water slurry method is used, a
				heavier slurry mix must be used with the addition of inorganic drying or
				stabilizing chemicals such as calcium chloride, sodium bicarbonate, or soda ash
				to assist in the effective plugging and stability of the bentonite column in
				the hole.
(c) In completely dry
				holes, plugging shall be accomplished by filling the hole with not less than 50
				pounds of coarse ground bentonite followed by the cuttings. The returned
				cuttings shall be tamped to insure the hole is not bridged. The hole shall be
				filled to a depth of 3 feet below the surface and the commercial plug set and
				topped with cuttings and soil as prescribed by paragraph (3) (a).
(i) With approval of the board's designated
				inspector, the shot hole may be plugged by filling the hole with the
				bentonite-water slurry mixture as set forth in paragraph (a).
(d) Seismic shot holes that crater
				or slough at the surface after being shot shall be plugged as set forth in
				subsections (3), (a) and (b) insofar as those procedures are reasonably
				possible. However, deviations from those procedures are permissible as
				circumstances may dictate, provided the procedures are designed to accomplish
				the primary objective of containing waters penetrated by the hole to their
				native strata and restoring the surface as near as practicable to its original
				conditions. The board and surface owner shall be notified of such
				deviations.