(1) All wells which
are to be plugged and abandoned may be filled with a mud fluid of sufficient
weight to offset the hydrostatic pressure of any formation penetrated.
Sufficient cement plugs shall be efficiently placed in number and properly
located as to prevent the commingling of oil, gas, salt water, and fresh water
from one zone to another, and to isolate potentially minable coal beds and
seams and other potentially extractable minerals. All downhole plugs may be
"felt for" to insure that they have been properly placed.
(2) The specific method and procedure for
plugging a well shall be as follows:
(a) A
mechanical plug, or a brush-and-stone plug, and a neet cement plug of not less
than 25 feet in length shall be placed between each geologic group or
formation.
(b) A mechanical plug,
or a brush-and-stone plug, and a neet cement plug of not less than 50 feet in
length shall be placed below the base of the surface casing. The plug shall be
placed so that at least 25 feet of cement is below the base of the surface
casing and extends up into the casing 25 feet.
(c) A mechanical plug, or a brush-and-stone
plug, and a neet cement plug of not less than 25 feet shall be placed at the
surface of the well. The surface casing shall be cut off below plow depth at
the request of the landowner or when determined appropriate by the Supervisor
or his representative.
(d) In a
well with casing that does not seal off the ground water, a mechanical plug, or
a brush-and-stone plug, and a neet cement plug shall be set 100 feet below the
deepest known ground water strata. The cement plug shall be adequate in length
to reach at least 10 feet into the casing.
(e) In an uncased well, a mechanical plug, or
a brush-and-stone plug, and a neet cement plug shall be set at least 50 feet
below the deepest ground water strata and extend up to the surface or just
below plow depth if appropriate.
(f) The mechanical plug or the
brush-and-stone plug method may be replaced by filling the well from total
depth to the surface with cement, provided, however, that such method shall be
either prescribed or approved by the Supervisor.
(g) If there is fluid in the well, a dump
bailer or tubing may be used to place the cement in the well.
(h) If drill water or mud is present it may
be used as filler between the plugs.
(i) If any casing has been installed in the
well and has not been cemented to the surface the casing shall be pulled prior
to the plugging of the well. If the casing cannot be readily removed the casing
shall be shot and then pulled.
(3) Any other methods not defined above, but
approved by the Supervisor, may be used.
