(a) For wells
drilled, altered, reconditioned or recompleted after February 5, 2011, surface
casing or any casing functioning as a water protection casing may not be
utilized as production casing unless one of the following applies:
(1) In oil wells where the operator does not
produce any gas generated by the well and the annulus between the surface
casing and the production pipe is left open.
(2) The operator demonstrates that the
pressure in the well is no greater than the pressure permitted under §
78a.73(e)
(relating to general provision for well construction and operation),
demonstrates through a pressure test or other method approved by the Department
that all gas and fluids will be contained within the well, and installs a
working pressure gauge that can be inspected by the
Department.
(b) If the
well is to be equipped with threaded and coupled casing, the operator shall
drill a hole so that the diameter is at least 1 inch greater than the outside
diameter of the casing collar to be installed. If the well is to be equipped
with plain-end welded casing, the operator shall drill a hole so that the
diameter is at least 1 inch greater than the outside diameter of the casing
coupling.
(c) The operator shall
drill to approximately 50 feet below the deepest fresh groundwater or at least
50 feet into consolidated rock, whichever is deeper, and immediately set and
permanently cement a string of surface casing to that depth. Except as provided
in subsection (f), the surface casing may not be set more than 200 feet below
the deepest fresh groundwater except if necessary to set the casing in
consolidated rock. The surface hole shall be drilled using air, freshwater or
freshwater-based drilling fluid. Prior to cementing, the wellbore shall be
conditioned to ensure an adequate cement bond between the casing and the
formation. The surface casing seat shall be set in consolidated rock. When
drilling a new well or redrilling an existing well, the operator shall install
at least one centralizer within 50 feet of the casing seat and then install a
centralizer in intervals no greater than every 150 feet above the first
centralizer.
(d) The operator shall
permanently cement the surface casing by placing the cement in the casing and
displacing it into the annular space between the wall of the hole and the
outside of the casing.
(e) Where
potential oil or gas zones are anticipated to be found at depths within 50 feet
below the deepest fresh groundwater, the operator shall set and permanently
cement surface casing prior to drilling into a stratum known to contain, or
likely containing, oil or gas.
(f)
If additional fresh groundwater is encountered in drilling below the
permanently cemented surface casing, the operator shall document the depth of
the fresh ground water zone in the well record and protect the additional fresh
groundwater by installing and cementing a subsequent string of casing or other
procedures approved by the Department to completely isolate and protect fresh
groundwater. The string of casing may also penetrate zones bearing salty or
brackish water with cement in the annular space being used to segregate the
various zones. Sufficient cement shall be used to cement the casing to the
surface. The operator shall install at least one centralizer within 50 feet of
the casing seat and then install a centralizer in intervals no greater than, if
possible, every 150 feet above the first centralizer.
(g) The operator shall set and cement a coal
protective string of casing through workable coal seams. The base of the coal
protective casing shall be at least 30 feet below the lowest workable coal
seam. The operator shall install at least two centralizers. One centralizer
shall be within 50 feet of the casing seat and the second centralizer shall be
within 100 feet of the surface.
(h)
Unless an alternative method has been approved by the Department in accordance
with §
78a.75 (relating to alternative
methods), when a well is drilled through a coal seam at a location where the
coal has been removed or when a well is drilled through a coal pillar, the
operator shall drill to a depth of at least 30 feet but no more than 50 feet
deeper than the bottom of the coal seam. The operator shall set and cement a
coal protection string of casing to this depth. The operator shall equip the
casing with a cement basket or other similar device above and as close to the
top of the coal seam as practical. The bottom of the casing must be equipped
with an appropriate device designed to prevent deformation of the bottom of the
casing. The interval from the bottom of the casing to the bottom of the coal
seam shall be filled with cement either by the balance method or by the
displacement method. Cement shall be placed on top of the basket between the
wall of the hole and the outside of the casing by pumping from the surface. If
the operator penetrates more than one coal seam from which the coal has been
removed, the operator shall protect each seam with a separate string of casing
that is set and cemented or with a single string of casing which is stage
cemented so that each coal seam is protected as described in this subsection.
The operator shall cement the well to isolate workable coal seams from each
other.
(i) If the operator sets and
cements casing under subsection (g) or (h) and subsequently encounters
additional fresh groundwater zones below the deepest cemented casing string
installed, the operator shall protect the fresh groundwater by installing and
cementing another string of casing or other method approved by the Department.
Sufficient cement shall be used to cement the casing to the surface. The
additional casing string may also penetrate zones bearing brackish or salt
water, but shall be run and cemented prior to penetrating a zone known to or
likely to contain oil or gas. The operator shall install at least one
centralizer within 50 feet of the casing seat and then, if possible, install a
centralizer in intervals no greater than every 150 feet above the first
centralizer.
(j) If it is
anticipated that cement used to permanently cement the surface casing cannot be
circulated to the surface a cement basket may be installed immediately above
the depth of the anticipated lost circulation zone. The casing shall be
permanently cemented by the displacement method. Additional cement may be added
above the cement basket, if necessary, by pumping through a pour string from
the surface to fill the annular space. Filling the annular space by this method
does not constitute permanently cementing the surface or coal protective casing
under §
78a.83b (relating to casing and
cementing-lost circulation).