NR 812.15(3)(3)Construction requirements in unconsolidated formations. In addition to the general requirements of this section and the requirements specified in ss. NR 812.10 to NR 812.13, a well driller or well constructor shall construct or reconstruct a flowing well in unconsolidated formations according to all of the following requirements:
NR 812.15(3)(a)(a) Upper enlarged drillhole. An upper enlarged drillhole shall be constructed to at least 25 feet or halfway through any known confining bed, whichever is deeper, except when the well is double cased in accordance with par. (e).
NR 812.15(3)(b)(b) Minimum diameter. The upper enlarged drillhole shall be a minimum of 4 inches larger than the nominal diameter of any casing to be grouted, except as allowed under par. (e).
NR 812.15(3)(c)(c) Method of keeping the hole open. The upper enlarged drillhole shall be kept open during construction using any of the following methods:
NR 812.15(3)(c)1.1. Driving temporary casing to the depth specified in par. (a).
NR 812.15(3)(c)2.2. Circulating drilling mud with a weight of at least 9 pounds per gallon. Additives approved under s. NR 812.091 may be added to the drilling mud to increase the mud weight.
NR 812.15(3)(d)(d) Screens. A well screen may be placed according to the requirements specified in s. NR 812.13 (4) prior to grouting.
NR 812.15(3)(e)(e) Double cased wells. When a well is double cased, it shall be constructed in accordance with all of the following requirements:
NR 812.15(3)(e)1.1. The nominal casing diameter of the outer casing may be reduced to a minimum of 2 inches in diameter greater than the nominal diameter of the inner casing when welded steel or flush-threaded thermoplastic casing is used for an inner casing.
NR 812.15(3)(e)2.2. An upper enlarged drillhole shall be constructed into the confining bed in accordance with par. (c).
NR 812.15(3)(e)3.3. The outer casing shall be placed in the upper enlarged drillhole and grouted in place according to the requirements specified in sub. (2). The grout shall be allowed to set for a minimum of 24 hours before drilling continues.
NR 812.15(3)(e)4.4. A second upper enlarged drillhole shall be constructed to at least the minimum casing depth for the formation encountered and in accordance with par. (c).
NR 812.15(3)(e)5.5. The inner casing shall be placed in the upper enlarged drillhole and grouted in place according to the requirements specified in sub. (2). The grout shall be allowed to set for a minimum of 24 hours before drilling continues.
NR 812.15(4)(4)Construction requirements in bedrock formations. In addition to the general requirements of this section and the requirements specified in ss. NR 812.10 to 812.14, a well driller or well constructor shall construct or reconstruct a flowing well in bedrock formations according to all of the following requirements:
NR 812.15(4)(a)(a) Upper enlarged drillhole.
NR 812.15(4)(a)1.1. An upper enlarged drillhole shall be constructed to the minimum casing depth for the bedrock formation encountered or halfway through any known confining bed, whichever is deeper, except when the well is double cased in accordance with par. (e).
NR 812.15(4)(a)2.2. When the depth to the top of bedrock is more than the minimum casing depth for the bedrock formation encountered, the upper enlarged drillhole depth may be reduced to 25 feet below ground surface when steel casing is driven or advanced according to the requirements of sub. (2) (b).
NR 812.15(4)(b)(b) Minimum diameter. The upper enlarged drillhole shall be a minimum of 4 inches larger than the nominal diameter of any casing to be grouted, except when the well is double cased in accordance with par. (e).
NR 812.15(4)(c)(c) Method of keeping the hole open. The upper enlarged drillhole shall be kept open during construction using any of the following methods:
NR 812.15(4)(c)1.1. Driving temporary casing to the depth of casing setting or to the top of bedrock.
NR 812.15(4)(c)2.2. Circulating drilling mud with a weight of at least 9 pounds per gallon. Approved additives may be added to the drilling mud to increase the mud weight.
NR 812.15(4)(d)(d) Seating casing. Any casing set into an upper enlarged drillhole constructed more than 5 feet into bedrock shall be driven to a firm seat prior to grouting the annular space.
NR 812.15(4)(e)(e) Double cased wells. When a well is double cased in bedrock, it shall be constructed in accordance with all of the following requirements:
NR 812.15(4)(e)1.1. The outer casing may be reduced to a minimum of 2 inches in diameter greater than the nominal diameter of the inner casing when welded steel casing is used as an inner casing. The minimum diameter of an inner casing is 6 inches.
NR 812.15(4)(e)2.2. An upper enlarged drillhole shall be constructed into the confining bed in accordance with par. (c).
NR 812.15(4)(e)3.3. The outer casing shall be placed in the upper enlarged drillhole and grouted in place according to the requirements specified in sub. (2). The grout shall be allowed to set for a minimum of 24 hours before drilling continues.
NR 812.15(4)(e)4.4. A second upper enlarged drillhole shall be constructed to at least the minimum casing depth for the formation encountered and in accordance with par. (c).
NR 812.15(4)(e)5.5. The inner casing shall be placed in the upper enlarged drillhole and grouted in place according to the requirements specified in sub. (2). The grout shall be allowed to set for a minimum of 24 hours before drilling continues.
NR 812.15 HistoryHistory: CR 18-095: r. and recr. Register June 2020 No. 774, eff. 7-1-20; correction in (4) (intro.) made under s. 35.17, Stats., Register June 2020 No. 774; CR 21-070: am. (2) (c) Register July 2022 No. 799, eff. 8-1-22.