A water well rehabilitation system is provided for a water well having an open borehole through an aquifer substrate which extends to the bottom of the water well. The system includes an acid injection assembly having a concentrated acid supply, a water supply, and an eductor to mix the concentrated acid with water to form an acid solution to inject into one or more predetermined elevations in the open borehole. An acid injection control assembly includes a concentrated acid control valve and a water supply control valve cooperatively operative to maintain a predetermined acid concentration in the acid solution formed in and discharged from the eductor. A flush water assembly is disposed to inject an amount of flush water into the water well, and a well monitoring assembly monitors at least one operating parameter while a rehabilitation process is being performed in the water well.

A system for preventive well maintenance with pumping equipment in the well for well rehabilitation using CO.sub.2 with varying lengths of producing intervals utilizing varying methods to deliver cleaning energy and varying porosity of aquifers to determine varying quantities of energy over the entire well structure.

According to an embodiment, there is provided a method for mitigating seawater intrusion in the ground where an aquifer having a seawater-fresh water interface is formed, the method including: installing an injection well at a point on an inland area, spaced apart from the sea by a predetermined distance, to a predetermined injection depth (d), the injection well having a predetermined screen height; injecting seawater into the aquifer by a predetermined quantity of injection through the injection well; and forming an upper seawater area around the injection well by the injection of the seawater, wherein the upper seawater area is an area that is filled with seawater in an upper portion of the aquifer.

Apparatuses and method to reduce a pore-water pressure of water within a subsurface formation below a first pressure, include creating a pressure discontinuity in a well for a first period of time. The pressure discontinuity is created using ambient ground water pressure. A ground water flow regulating device (GFRD) is used to create the pressure discontinuity such that the GFRD restricts ground water flow through the well, which causes a pressure below the GFRD to increase. A flow of ground water is released through the well casing after the first period of time under natural ground water pressure. The GFRD releases the flow of the ground water and the pore-water pressure decreases to a second pressure after the ground water is released and the second pressure is less than the first pressure, wherein a first purge cycle is accomplished.

Apparatuses and method to reduce a pore-water pressure of water within a subsurface formation below a first pressure, include creating a pressure discontinuity in a well for a first period of time. The pressure discontinuity is created using ambient ground water pressure. A ground water flow regulating device (GFRD) is used to create the pressure discontinuity such that the GFRD restricts ground water flow through the well, which causes a pressure below the GFRD to increase. A flow of ground water is released through the well casing after the first period of time under natural ground water pressure. The GFRD releases the flow of the ground water and the pore-water pressure decreases to a second pressure after the ground water is released and the second pressure is less than the first pressure, wherein a first purge cycle is accomplished.

A large diameter injection water well is drilled using a drilling derrick and rotary drilling techniques after snubbing in and drilling a short distance with drilling mud, a temporary drilling header is installed below the blowout preventers. Extending downward from the temporary drilling header is a drop pipe with a valve on the lower end thereof. Drilling pipe with attachments on the lower end thereof, are lowered into the drop pipe with the valve closed. After sealing to the drilling pipe, the valve is opened and the drilling pipe and attachments are lowered to the bottom of the well for the normal drilling operation. Thereafter, the drilling pipe and attachments are removed reversing the process of retracting into the drop pipe and closing the valve before removing the seal from the drilling pipe. The repeated insertion of the drilling pipe with various attachments on the end thereof in the drilling procedure occurs without having to kill or suppress the well until the final step when removing the drop pipe.

A large diameter injection water well is drilled using a drilling derrick and rotary drilling techniques after snubbing in and drilling a short distance with drilling mud, a temporary drilling header is installed below the blowout preventers. Extending downward from the temporary drilling header is a drop pipe with a valve on the lower end thereof. Drilling pipe with attachments on the lower end thereof, are lowered into the drop pipe with the valve closed. After sealing to the drilling pipe, the valve is opened and the drilling pipe and attachments are lowered to the bottom of the well for the normal drilling operation. Thereafter, the drilling pipe and attachments are removed reversing the process of retracting into the drop pipe and closing the valve before removing the seal from the drilling pipe. The repeated insertion of the drilling pipe with various attachments on the end thereof in the drilling procedure occurs without having to kill or suppress the well until the final step when removing the drop pipe.

Disclosed is a shielding apparatus for high-depth groundwater well pollution prevention grouting comprising: a shielding portion which is provided on the outer circumferential surface of a grouting casing installed in an excavation hole in the ground and compressed to be in close contact with a hollow wall of the excavation hole; a compression portion which is provided on the outer circumferential surface of the grouting casing and formed to descend toward the shielding portion and brings the shielding portion into close contact with the hollow wall of the excavation hole to guide the excavation hole to be sealed; and a pressure equalization injection tube portion which is connected with the compression portion on the outer circumferential surface of the grouting casing and lowers the compression portion by water pressure generated by supplying water from the outside through a water supply tube.

Disclosed is a shielding apparatus for high-depth groundwater well pollution prevention grouting comprising: a shielding portion which is provided on the outer circumferential surface of a grouting casing installed in an excavation hole in the ground and compressed to be in close contact with a hollow wall of the excavation hole; a compression portion which is provided on the outer circumferential surface of the grouting casing and formed to descend toward the shielding portion and brings the shielding portion into close contact with the hollow wall of the excavation hole to guide the excavation hole to be sealed; and a pressure equalization injection tube portion which is connected with the compression portion on the outer circumferential surface of the grouting casing and lowers the compression portion by water pressure generated by supplying water from the outside through a water supply tube.

Disclosed is a non-powered seawater pumping apparatus for reducing seawater intrusion in a land in which an aquifer with a seawater-fresh water boundary surface is formed. The seawater pumping apparatus includes a pumping pipe having two open end portions, a first end portion of the open end portions being positioned below a sea level and a second end portion being positioned below the seawater-fresh water boundary surface in the land, and a well disposed to surround a lateral surface of a land-buried portion of the pumping pipe, which is buried in the land, so as to space away the land-buried portion of the pumping pipe from the land. The pumping pipe is filled with seawater, and the well comprises a screen having a plurality of through holes formed along a circumference of the well at a lower end portion of the well.