The well construction described in this section may be used for private and reasonable domestic use wells and for noncommercial livestock watering wells as an alternative to the construction required by § 74:02:04:28. All other wells, including public water supply wells, shall be constructed as required by § 74:02:04:28. If any of the following requirements cannot be met, the well construction must comply with requirements of § 74:02:04:28. The following alternative well construction may be used to construct wells which are completed into the Dakota aquifer in the Kennedy Basin, Sioux Ridge, the Canadian Shield, and the eastern portion of the Williston Basin if the following requirements are met:

1. (1) The drill bit used to drill into the Dakota aquifer is no larger than four and one-half inches in diameter;
2. (2) The vertical distance between the ground surface and the top of the Greenhorn formation is more than 300 feet;
3. (3) The size of the production casing installed to the top of the production aquifer, below any larger upper casing which is installed to allow installation of a pump is no larger than two inches in diameter and is type K hard copper, schedule 80 thermoplastic, brass, or stainless steel. The casing must be installed in accordance with the manufacturer's recommendations;
4. (4) Packers are located above the Dakota as necessary to help form a seal to stop movement of mud, silt, or other aquifer water into the Dakota aquifer well. Packers made from burlap bags, gunny sacks, or similar materials are prohibited. Local conditions may require use of other construction techniques in lieu of packers; however, the well driller shall construct the well to prevent movement of mud, silt, or other aquifer water into the Dakota aquifer well;
5. (5) The production casing and packers are not installed unless the weight of the drilling fluid is heavy enough to overcome aquifer pressures;
6. (6) If any flow of water at the surface outside the casing does not stop within a reasonable length of time, the well driller shall pressure-grout the upper portion of the casing with cement grout using a tremie pipe to a depth of 300 feet or into unweathered clay or shale, whichever depth is greater;
7. (7) Only one casing is placed into the production aquifer of a new well. New wells double-cased into the production aquifer are prohibited. However, if the original casing becomes defective, the well may be rehabilitated by placing new casing inside the old defective casing; and

8. (8) In those locations where pressures greater than 50 pounds per square inch at the surface may be encountered in the Dakota aquifer, to assure compliance with § 74:02:04:73, surface casing is installed and pressure-grouted with cement grout to a depth of at least 300 feet or into an unweathered clay or shale formation, whichever depth is greater.

   See Appendix F at the end of this chapter.

   Note: Although this type of well construction may be less expensive, it is more likely to fail than a well constructed and grouted pursuant to § 74:02:04:28. The success of this type of well construction is dependent upon the use of packers or other sealing techniques outside the casing above the Dakota aquifer and the sloughing off of the shale above the Dakota to fill and seal the drill hole annulus outside the casing, preventing movement of water, mud, or silt into the Dakota aquifer well or movement of water on the outside of the casing between aquifers or to the surface. When aquifer pressures above the Dakota are great enough to overcome the Dakota pressure, the success of the well is also dependent upon establishing a packer and shale seal just above the Dakota before the remainder of the annulus toward the surface is sealed. Water may flow outside the casing to the surface for a short period of time until an annulus seal is established even though the well does not produce a flow from the Dakota. If any flow toward the surface is sealed off first, the packer and shale seal may not be established and the well may produce silt or muddy water or water of a different chemical quality.

Source: 12 SDR 50, effective September 29, 1985; 13 SDR 129, 13 SDR 141, effective July 1, 1987; 18 SDR 224, effective July 16, 1992.

General Authority: SDCL 46-2-5 , 46-6-20 , 46-6-27.

Law Implemented: SDCL 46-6-6.1 , 46-6-10 , 46-6-20 , 46-6-27.