Abstract:
An apparatus for remediating water wells comprises a plurality of retractable cutting blades suitable for cutting openings in a well casing. The retractable cutting blades and corresponding drive mechanism are organized to be lowered through a well casing. At certain depths, the retractable blades are extended to cut openings in the well casing. The apparatus also includes inflatable retention elements both above and below the retractable blades to create a fluid seal within the well casing. A solidifying, waterproof slurry is injected to flow through the openings via a slurry delivery mechanism, and thereby create a waterproof barrier outside the well casing at the level of a waterproof confining soil layer.

Description:
PRIORITY 
     The present application claims the benefit under 35 U.S.C. §119(e) of U.S. Provisional Application Ser. No. 61/917,567, filed Dec. 18, 2013, which is incorporated herein by reference. 
    
    
     FIELD OF THE INVENTION 
     The present invention is directed generally toward water wells, and more particularly to water well remediation. 
     BACKGROUND OF THE INVENTION 
     Water wells are produced by drilling a borehole from the surface to an appropriate depth of a water bearing layer. Generally, the borehole must traverse a waterproof confining layer. When the confining layer is penetrated, fluids such as chemical contaminants can flow from the surface to the water bearing layer. When a well pipe casing is installed in the borehole, the well casing generally does not fill the entire borehole. The space between the periphery of the well casing and the wall of the borehole is generally filled with a non-waterproof aggregate. Therefore, most existing water wells, including those on farms where fertilizer and pesticide use is common, allow fluids to flow between the wall of the borehole and the well casing, past the penetrated confining layer, into the water bearing layer. 
     Even when water wells are abandoned, the process for abandoning and sealing a water well does not remedy the gap in the confining layer between the borehole wall and the well casing. Generally an abandoned water well is sealed by filling the well casing with bentonite and capping the well. However, contaminant fluids can percolate through soil down to the confining layer and flow laterally until reaching the point where the confining layer was penetrated by the borehole. The current process of sealing a water well therefore permits contaminants to flow into the water bearing layer, where they may be taken up by other, active wells. 
     Consequently, it would be advantageous if an apparatus existed that is suitable for remediating water wells and permanently sealing water wells that prevents contaminants from entering the water supply. 
     SUMMARY OF THE INVENTION 
     Accordingly, the present invention is directed to a novel method and apparatus for remediating water wells and permanently sealing water wells that prevents contaminants from entering the water supply. 
     In at least one embodiment of the present invention, an apparatus comprises a plurality of retractable cutting blades suitable for cutting openings through a water well casing. The retractable cutting blades and corresponding drive mechanism are organized to be lowered through a water well casing. At certain depths, the retractable blades are extended to cut openings in the casing. The apparatus also includes inflatable retention elements both above and below the retractable blades to create a fluid seal within the casing. A slurry is then injected to flow through the grooves via a delivery mechanism. 
     In another embodiment of the present invention, a method for remediating water wells includes identifying a well depth corresponding to a waterproof confining soil layer. Openings are cut into the well casing, from inside the well casing, to allow access to the surrounding soil. An enclosed segment is created by inflating upper and lower air bags relative to the openings in the casing, and a fluid is pumped into the enclosed segment such that the fluid flows out the openings into the space between the borehole wall and the casing. The fluid then partially solidifies. Once the fluid is partially solidified, the air bags are partially deflated such that they no longer create a frictional seal with the casing, but are rigid enough to allow the partially solidified fluid plug in the casing to be removed. 
     It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention claimed. The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate an embodiment of the invention and together with the general description, serve to explain the principles. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The numerous advantages of the present invention may be better understood by those skilled in the art by reference to the accompanying figures in which: 
         FIG. 1  shows a cross-sectional environmental view of a water well; 
         FIG. 2  shows a side view of one embodiment of the present invention; 
         FIG. 3  shows a cross-sectional environmental view of a water well after an embodiment of the present invention has been utilized; 
         FIG. 4  shows a cross-sectional side view of one embodiment of the present invention; 
         FIG. 5  shows a cross-sectional environmental view of a water well after an embodiment of the present invention has been utilized; 
         FIG. 6  shows a cross-sectional environmental view of a water well; 
         FIG. 7  shows a cross-sectional side view of one embodiment of the present invention; 
         FIG. 8  shows a cross-sectional top view of one embodiment of the present invention; 
         FIG. 9  shows a cross-sectional top view of one embodiment of the present invention; 
         FIG. 10  shows a cross-sectional environmental view of one embodiment of the present invention; 
         FIG. 11  shows a flowchart of one embodiment of the present invention; 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Reference will now be made in detail to the subject matter disclosed, which is illustrated in the accompanying drawings. The scope of the invention is limited only by the claims; numerous alternatives, modifications and equivalents are encompassed. For the purpose of clarity, technical material that is known in the technical fields related to the embodiments has not been described in detail to avoid unnecessarily obscuring the description. 
     Referring to  FIG. 1 , a cross-sectional environmental view of a water well is shown. Where water wells are drilled, the ground is generally composed of a plurality of distinct layers such as a topsoil layer  100 , a semi-confining layer  102 , a sub-soil layer  104  and a confining layer  106 ; all above a potable water bearing layer  108 . In undisturbed soil, surface water can penetrate the topsoil layer  100 , the semi-confining layer  102  and the sub-soil layer  104 , but cannot penetrate the confining layer  106 . 
     A water well is produced by drilling a borehole from the surface to the potable water bearing layer  108  and inserting a casing  110  into the borehole. Generally the casing  110  comprises a plurality of pipe segments joined together to reach a desirable depth. The casing  110  is generally a smaller diameter than the borehole. The space between the wall of the borehole and the casing  110  is filled with some permeable aggregate material  112 . 
     Once the casing  110  and aggregate material  112  are in place, surface water may percolate from the surface, or any of the water permeable layers above the confining layer  106 , through the aggregate material  112  into the potable water bearing layer  108 . In some cases, surface water and water from any of the water permeable layers may include chemicals and contaminants that are undesirable in the potable water bearing layer  108 . 
     Referring to  FIG. 2 , a side view of one embodiment of the present invention is shown. In at least one embodiment, an apparatus includes a plurality of cutting blades  204  configured to cut openings into a water-well casing from inside the casing. The plurality of cutting blades  204  may be organized onto one or more shafts, each rotationally driven by blade motor  208  such as a hydraulic motor. Each organization of cutting blades  204 , shaft and blade motor  208  may be organized into a linear configuration and connected to a support shaft  206  through one or more blade motor pivot mounts  212  and one or more blade shaft mounts  214 . Each cutting blade  204  and blade motor  208  assemblage may be configured to rotate about the corresponding support shaft  206  upon the corresponding blade motor pivot mounts  212  and blade shaft mounts  214 , actuated by one or more blade extension actuators  210 . The blade extension actuators  210  may be hydraulic or electric actuators, or any other mechanism capable extending and retracting each corresponding assemblage to engage a water-well casing. 
     In at least one embodiment, one or more cutting blade  204  and blade motor  208  assemblages, when retracted, are contained within a space defined one or more casing diameter plates  202  configured to allow insertion of the apparatus into a water-well casing. The apparatus may include a rotational element  200  to rotate the apparatus within a water-well casing to allow the cutting blades to cut multiple openings in the water-well casing at certain desirable depths. 
     A person skilled in the art may appreciate that while the cutting blade  204  and blade motor  208  assemblages are shown in a vertical orientation, such assemblages may also be operable in a horizontal orientation whereby the support shafts  206  are rotated ninety degrees and each corresponding element is adjusted accordingly. Furthermore, a person skilled in the art may appreciate that cutting blade  204  and blade motor  208  assemblages may be offset from each other such that the cutting blades  204  from a first assemblage may nest between the cutting blades  204  of a second assemblage when the assemblages are retraced, thereby allowing for larger cutting blades  204 . 
     While circular cutting blades  204  are shown, it is anticipated that a chainsaw type cutting apparatus may be used to cut openings into the water-well casing. In such an embodiment, elongated chainsaw type cutting blades may be actuated about a support shaft  206  or other structure to temporarily engage the water-well casing. 
     Referring to  FIG. 3 , a cross-sectional environmental view of a water well after an embodiment of the present invention has been utilized is shown. Where the ground is composed of a plurality of distinct layers such as a topsoil layer  300 , a semi-confining layer  302 , a sub-soil layer  304  and a confining layer  306 , and surface water can penetrate the topsoil layer  300 , the semi-confining layer  302  and the sub-soil layer  304 , but cannot penetrate the confining layer  306 , an apparatus according to the present invention may be lowered into the open casing  310  and lowered to the known depth of the confining layer  306 . One or more blade extension actuators then extend a retracted cutting blade assemblage with one or more rotating cutting blades to cut one or more sealant openings  314  into the casing from the inside. At the known depth of the confining layer  306 , or some predetermined distance above such depth, the apparatus may be rotated within the casing  310  and the cutting blades extended several times such that one set of cutting blades may be used to produce more than one set of sealant openings  314  at such depth. Sealant openings  314  may be cut above the depth of the confining layer  306  to account for gravity. 
     In another embodiment of the present invention, an apparatus according to the present invention may be lowered into the open casing  310  and periodically lowered to a known depth corresponding to each joint in the casing  310 , or just above each joint in the casing  310 . One or more blade extension actuators then extend a retracted cutting blade assemblage with one or more rotating cutting blades to cut one or more sealant openings  314  into the casing from the inside. At each joint, the apparatus may be rotated within the casing  310  and the cutting blades extended several times such that one set of cutting blades may be used to produce more than one set of sealant openings  314 . Sealant openings  314  may be cut above the depth of joint in the casing  310  to account for gravity. 
     Referring to  FIG. 4 , a cross-sectional side view of one embodiment of the present invention is shown. In one embodiment of the present invention, an apparatus for producing a contained, directed flow of sealant within a casing  410  includes an upper inflatable containment element  402  and a lower inflatable containment element  404 . The apparatus may be lowered into a casing  410  such that the upper inflatable containment element  402  is positioned above a set of sealant openings  414  and the lower inflatable containment element  404  is positioned below the set of sealant openings  414 . A fluid is pumped into the upper inflatable containment element  402  through an upper inflatable element delivery mechanism  412  and a fluid is pumped into the lower inflatable containment element  404  through a lower inflatable element delivery mechanism  418 . The upper inflatable containment element  402  and lower inflatable containment element  404  form a fluid tight seal with the casing  410  and define a sealant fluid injection chamber  422  with access to the sealant openings  414 . A water impermeable sealant is pumped into the sealant fluid injection chamber  422  and through the sealant openings  414 . Sealant may flow through the sealant openings  414  into the aggregate material surrounding the casing  410  to form a water impermeable layer in the aggregate. Sealant may be delivered to the sealant fluid injection chamber  422  through one or more sealant circulation mechanisms  416 ,  420 . A person skilled in the art may appreciate the advantages of a first sealant fluid circulation mechanism  420  devoted to delivering sealant fluid to the sealant fluid injection chamber  422  and a second sealant fluid circulation mechanism  416  devoted to returning circulating sealant fluid. 
     In at least one embodiment, the sealant used may become progressively more solid over time according to a known algorithm associated with the particular sealant. After the sealant has been delivered, and after a period of time sufficient to allow the sealant to become semi-rigid, the upper inflatable containment element  402  and the lower inflatable containment element  404  may be depressurized and the apparatus raised out of the casing  410 , thereby shearing any connection between sealant in the sealant fluid injection chamber  422  and in the sealant openings  414 . When the sealant is fully cured, the sealant openings  414  may be sealed and a water impermeable layer formed where the sealant was forced through the aggregate surrounding the casing  410 . 
     In at least one embodiment, sealant fluid openings  414  are cut into a casing  410  at a depth corresponding to a confining soil layer to produce a water well where no contaminant may flow into the potable water bearing layer through spaces around the casing  410 . In at least one other embodiment, sealant fluid openings  414  are cut into a casing  410  at each joint in the casing  410  to seal such joints form the outside and thereby prevent contaminants from seeping through such joints over time. 
     Referring to  FIG. 5 , a cross-sectional environmental view of a water well after an embodiment of the present invention has been utilized is shown. Where water can penetrate a topsoil layer  500 , a semi-confining layer  502  and a sub-soil layer  504 , but cannot penetrate the confining layer  506 , an apparatus according to the present invention may be lowered into the open casing  510  and at each joint of the casing  510  sealant openings  514  may be cut to allow a sealant fluid to be forced in surrounding aggregate and seal the joints from the outside. Furthermore, sealant openings  514  may be cut into the casing  510  at a depth corresponding to the confining layer  506  to create a substantially continuous water impermeable layer, sealing the portion of the confining layer  506  penetrated by the borehole. 
     Referring to  FIG. 6 , a cross-sectional environmental view of a water well is shown. In a water well where a casing  610  has penetrated a topsoil layer  600 , a semi-confining layer  602 , a sub-soil layer  604  and a confining layer  606 , scale  614  or other mineralization may seep through each joint of the casing  610  to partially occlude the casing  610 . 
     Referring to  FIG. 7 , a cross-sectional side view of one embodiment of the present invention is shown. In at least one embodiment, an apparatus includes a plurality of scale brushes  704  configured to grind off or otherwise remove scale buildup from an interior surface of a water-well casing. The plurality of scale brushes  704  may be organized onto one or more shafts, each rotationally driven by scale brush motor  708  such as a hydraulic motor. Each organization of scale brush  704 , shaft and scale brush motor  708  may be organized into a linear configuration and connected to a support shaft  706  through one or more scale brush motor pivot mounts  712  and one or more brush shaft mounts  714 . Each scale brush  704  and scale brush motor  708  assemblage may be configured to rotate about the corresponding support shaft  706  upon the corresponding scale brush motor pivot mounts  712  and blade shaft mounts  714 , actuated by one or more brush extension actuators  710 . The brush extension actuators  710  may be hydraulic or electric actuators, or any other mechanism capable extending and retracting each corresponding assemblage to engage a water-well casing. 
     In at least one embodiment, one or more scale brush  704  and scale brush motor  708  assemblages, when retracted, are contained within a space defined one or more casing diameter plates  702  configured to allow insertion of the apparatus into a water-well casing. The apparatus may include a rotational element  700  to rotate the apparatus within a water-well casing to allow the scale brushes to clean extended portions of the interior of the water-well casing. 
     A person skilled in the art may appreciate that while the scale brush  704  and scale brush motor  708  assemblages are shown in a vertical orientation, such assemblages may also be operable in a horizontal orientation. Furthermore, a person skilled in the art may appreciate that scale brush  704  and scale brush motor  708  assemblages may be offset from each other such that the scale brushes  704  from a first assemblage may nest between the scale brushes  704  of a second assemblage when the assemblages are retraced, thereby allowing for larger scale brushes  704 . 
     Referring to  FIG. 8 , a cross-sectional top view of one embodiment of the present invention is shown. At least one embodiment of the present invention includes one or more casing diameter plates  802  configured to fit within a casing  810 . The apparatus includes two or more scale brushes  804  configured to retract within a volume defined by the one or more casing diameter plates  802 . 
     Referring to  FIG. 9 , a cross-sectional top view of one embodiment of the present invention is shown. In the embodiment shown in  FIG. 8 , one or more the two or more scale brushes  804  are extended beyond the volume defined by the one or more casing diameter plates  802  while rotating to remove scale from the interior surface of a water-well casing. Scale brushes  804  may counter-rotate to minimize stress on the apparatus. A person skilled in the art may appreciate that while  FIGS. 8 and 9  specifically show scale brushes  804 , such representations would be equally applicable to an embodiment having a plurality of cutting blades as described herein. 
     Referring to  FIG. 10 , a cross-sectional environmental view of one embodiment of the present invention is shown. Where water flowing through a topsoil layer  1000 , a semi-confining layer  1002  and a sub-soil layer  1004  can penetrate into joints in a casing  1010  to deposit scale  1014  at such joints, a scale cleaning apparatus  1016  according to the present invention may be lowered into the open casing  1010  and at each joint of the casing  1010  scale  1014  may be removed to prevent occlusion of the casing  1010 , and to prepare the casing  1010  for additional remediation. 
     Referring to  FIG. 11 , a flowchart of one embodiment of the present invention is shown. In at least one embodiment of the present invention, a water-well may be remediated to prevent undesirable chemicals from entering a potable water bearing layer of soil otherwise protected by a water impermeable confining layer. In one embodiment, the depth of the water bearing layer is determined  1100 , or alternatively the depth of the confining slayer is determined  1100 . An apparatus suitable for cutting sealant openings in the water-well casing cuts  1102  a plurality of sealant openings some distance above the confining layer. A suitable apparatus then creates  1104  a contained, enclosed segment within the casing, including the plurality of sealant openings. A sealant is then injected  1106  into the enclosed segment under sufficient pressure to force the sealant through the sealant openings, into the space surrounding the casing. The sealant may be drawn downward by gravity, so cutting  1102  the sealant openings slightly above the confining layer accounts for the tendency of the sealant to flow downward and thereby engage the confining layer. 
     The sealant may solidify over time. At some time after sealant injection  1106 , the sealant may be solidified enough such that the sealant in the enclosed segment may be removed  1108 . In one embodiment, the apparatus for creating  1104  the enclosed segment includes an upper and lower inflatable element to create a seal with the inner surface of the casing. Such inflatable elements may be partially deflated such that the apparatus may be removed from the casing and support any partially solidified sealant between the inflatable elements and the casing. 
     In another embodiment, each joint in a casing segment may be sealed. One or more well casing segment joints are identified  1110 . For each identified segment joint an apparatus is lowered  1114  to a segment joint and a plurality of sealant openings are cut  1116  into the casing. A contained, enclosed segment is created  1118  within the casing, including the plurality of sealant openings. A sealant is then injected  1120  into the enclosed segment under sufficient pressure to force the sealant through the sealant openings, into the space surrounding the casing. At some time after sealant injection  1120 , the sealant may be solidified enough such that the sealant in the enclosed segment may be removed  1122 . Such process may be repeated until all segment joints are sealed  1112 . 
     A person skilled in the art may appreciate that devices and methodologies according to the present invention may be utilized to remediate water wells or in conjunction with other processes to plug abandoned water wells. Furthermore, a person skilled in the art may appreciate that while processes for remediating water wells is described, other types of wells, or any borehole including a casing of inferior diameter, where contamination seeping from the surface is undesirable may benefit from the devices and methodologies described herein. 
     It is believed that the present invention and many of its attendant advantages will be understood by the foregoing description of embodiments of the present invention, and it will be apparent that various changes may be made in the form, construction, and arrangement of the components thereof without departing from the scope and spirit of the invention or without sacrificing all of its material advantages. The form herein before described being merely an explanatory embodiment thereof, it is the intention of the following claims to encompass and include such changes.