Current through August 26, 2024
A well driller or well constructor shall construct wells
terminating in unconsolidated material according to the requirements specified
in s. NR 812.12 and all of the following:
(1) MINIMUM DIAMETER. The minimum diameter
for all drilled wells in unconsolidated formations, based on nominal size of
well casing pipe, is 2 inches.
(2)
CASING DEPTH. Minimum casing depths shall be measured from the ground surface.
The minimum well casing pipe depth for all drilled wells in unconsolidated
formations, not including any screen, is 25 feet or 10 feet below the static
water level when the static water level is greater than 15 feet below ground
surface.
(3) CASING MATERIAL AND
INSTALLATION.
(a) Steel or thermoplastic well
casing pipe, as specified in s. NR 812.11 (6) or (7), shall be used for low
capacity wells and nonpotable high capacity wells.
(b) Thermoplastic casing may only be placed
in an upper enlarged drillhole and may not be driven or jetted into
place.
(c) Drilling tools such as
drill bits or stabilizers may not be placed in the thermoplastic well casing
pipe nor may any drilling or reconstruction occur after placement of the well
casing pipe in the well. This restriction does not prohibit the installation or
replacement of screens, or the insertion of equipment for the development and
cleaning of wells with screens.
(4) SCREENS. A well driller or well
constructor shall install an adequate screen when necessary to prevent sand
pumping conditions. Screens installed in a well shall meet the requirements of
s. NR 812.11 (11). A well driller or well constructor shall install screens
according to the following requirements:
(a)
Screen installation shall be accomplished in a manner that prevents damage to
the screen or casing and prevents material from bypassing the well
screen.
(b) A packer or shale trap
may be used to provide a sand seal between the bottom of a well casing pipe and
the top of a screen. Packers and shale traps shall meet the requirements of s.
NR 812.11 (13).
(c) A riser pipe
may be installed to extend upward from the top of the screen. The riser pipe
material shall be thermoplastic or metal provided the metal does not have a
lead content in excess of 0.25%.
(5) GRAVEL PACKS. The construction of a
gravel pack well shall comply with the additional requirements specified in s.
NR 812.16.
(6) DRIVING OR ADVANCING
STEEL WELL CASING. A well driller or well constructor shall drive or advance
casing according to the following requirements:
(a) The casing shall be equipped with a drive
shoe or casing shoe meeting the requirements specified in s. NR 812.11 (10).
(b) Clay slurry, sodium
bentonite slurry, or granular bentonite shall be maintained around the casing
during advancement using any of the following methods:
1. When casing is driven or advanced from the
ground surface, excavating a funnel-shaped depression around the casing to
create a reservoir, which shall be kept filled with dry granular bentonite. The
granular bentonite shall be kept dry at the surface during
advancement.
2. Filling a starter
drillhole or temporary outer casing with clay slurry or sodium bentonite slurry
and drill cuttings having a mud weight of at least 11 pounds per gallon, or
with dry granular bentonite, which shall be maintained around the outside of
the casing.
3. Constructing an
upper enlarged drillhole in accordance with sub. (7). The upper enlarged
drillhole shall be kept filled to within 10 feet of the ground surface with
clay slurry or sodium bentonite slurry and drill cuttings having a mud weight
of at least 11 pounds per gallon, or with dry granular bentonite.
(7) UPPER ENLARGED
DRILLHOLE. When an upper enlarged drillhole is constructed for any reason, it
shall be completed in accordance with all of the following requirements:
(a)
Minimum depth. The
minimum depth of an upper enlarged drillhole shall be one of the following:
1. To the final depth that the well casing is
set.
2. To the bottom of any clay
formation, or 20 feet, whichever is less when the casing is driven or
mechanically advanced as specified in sub. (6) (b) 3.
(b)
Minimum diameter. The
minimum diameter of an upper enlarged drillhole shall meet the following
requirements:
1. Four inches greater than the
nominal diameter of the casing or couplings.
2. A well driller or well constructor may
reduce the diameter of an upper enlarged drillhole to 3 inches greater than the
nominal diameter of the casing when flush-threaded thermoplastic casing is used
and the required sealing material, according to sub. (8), is placed in the
annular space using a pressure grouting method according to the requirements of
s. NR 812.20.
3. A well driller or
well constructor may reduce the upper enlarged drillhole to 2 inches greater
than the nominal diameter of the casing when welded steel casing is used and
the required sealing material, according to sub. (8), is placed in the annular
space using a pressure grouting method according to the requirements of s. NR 812.20.
(c)
Method of keeping hole open. A well driller or well
constructor shall maintain an upper enlarged drillhole at full diameter during
drilling by any of the following methods:
1.
Keeping the drillhole filled up to within 10 feet of the ground surface with
drilling mud.
2. Circulating
bentonite drilling mud.
3. Setting
a temporary outer casing.
(d)
Grouting. A well driller
or well constructor shall grout an upper enlarged drillhole according to the
requirements specified in sub. (8).
(8) GROUTING MATERIAL AND METHODS.
(a) Grouting material shall meet the
requirements of s. NR 812.11 (15) and shall be placed in an annular space in
accordance with the requirements specified in s. NR 812.20. A flowing well
shall be grouted using the materials specified in s. NR 812.15. A potable high
capacity well shall be grouted using the materials specified in s. NR 812.152.
(b) For a potable low
capacity or nonpotable high capacity well with steel casing, a well driller or
well constructor shall use one of the following materials:
1. Clay slurry or bentonite drilling mud and
cuttings when the upper enlarged drillhole is less than or equal to 20 feet in
depth.
2. Neat cement.
3. Sand-cement.
4. Sodium bentonite.
5. Sodium bentonite-sand.
(d) For a potable low capacity or
nonpotable high capacity well with thermoplastic casing, a well driller or well
constructor shall use one of the following materials:
1. Sodium bentonite.
2. Sodium bentonite-sand.
3. Neat cement.
4. Sand-cement.
(9) DUAL AQUIFER PROHIBITION. A
well driller or well constructor may not construct a well that is open to both
an unconsolidated formation and a bedrock formation.
