Abstract:
Apparatus and method for repairing underground conduits, such as well casings, particularly for repairing internal casings of deep wells. More particularly, the invention relates to a filter-sleeve and a method of conduit repair using such sleeve, without complete removal of the conduit or casing and without abandoning the well.

Description:
[0001]     This application is based upon U.S. Patent Application No. 60/541,938, filed on Feb. 6, 2004, the disclosure of which is hereby incorporated-by-reference thereto in its entirety and the priority of which is claimed under 35 USC § 119(e). 
     
    
     BACKGROUND OF THE INVENTION  
       [0002]     1. Field of the Invention  
         [0003]     The invention relates to repairs of underground conduits and, more particularly, repairs and linings of internal well casings. More particularly, the invention relates to such repairs and linings, utilizing a filter-sleeve, without complete removal of the casing or abandonment of the well.  
         [0004]     2. Description of Background and Relevant Information  
         [0005]     For the purpose of repairing an underground pipe, such as a well casing, it is commonly necessary to remove the casing or to abandon the well in favor of a new well in view of the limitations of known technology.  
         [0006]     A damaged well casing allows soil fines to enter the well. This can cause severe damage to pumps and other equipment.  
         [0007]     The state of the art of repairing well casings and other underground pipes and conduits remains in need of a convenient and effective method and apparatus for repairing and sealing underground conduits, pipes, and casings, including those with screen sections, without removing such conduits, pipes, and casings, including such repair consisting of a complete relining.  
       SUMMARY OF THE INVENTION  
       [0008]     An object of the invention is to provide for the structural repair and sealing of damaged underground conduits and pipes, particularly well casings, including casings having screen sections, by means of the installation of an expandable sleeve, thus creating support for the structurally weakened conduit, pipe, or casing.  
         [0009]     An additional object of the invention to provide for the repair of damaged screens and openings, which might be incorporated within a damaged conduit, with a filter that can prevent the ingress of fines and sand into such conduit.  
         [0010]     A still further object of the invention is to provide a means of continuing repair and maintenance of clogged and damaged filters with a screen that can be installed and removed for the purpose of replacement or cleaning, as the need arises.  
         [0011]     A still further object of the invention is to provide a means by which the service life of a well, or other underground conduit, can be extended.  
         [0012]     A sleeve according to the invention, hereafter referred to as a filter-sleeve, includes an expandable perforated non-corrodible core, such as a stainless steel core, equipped with a locking mechanism. The choice of core material is determined by the chemical regime in the well.  
         [0013]     The core of the sleeve, according to a particular embodiment of the invention, is surrounded by filter material. According an embodiment of the invention, O-rings or other types of soft, possibly elastic, support devices are positioned on the sleeve, which can press the filter tightly against the host pipe upon expansion and installation of the filter-sleeve, which can create the pressure needed to secure the sleeve in place.  
         [0014]     Installation, according to the invention, can be accomplished by use of an inflatable plug as an installation tool. Once the sleeve is expanded by means of the plug and locked by a locking device or other type of fastener, the plug is removed.  
         [0015]     Infiltrating water, upon installation of the filter-sleeve, can pass through the filter material and the perforated sleeve.  
         [0016]     The filter-sleeve of the invention provides an internal repair method and apparatus, designed for rehabilitation of conduits, pipes, well casings, and screens. The filter-sleeve can be used to repair holes, cracks, corrosion and other damage. 
     
    
     BRIEF DESCRIPTION OF DRAWINGS  
       [0017]     Other objects, features, and advantages of the invention will be become apparent from the description of preferred embodiments of the invention, when considered in light of the accompanying drawings, in which:  
         [0018]      FIG. 1  is a schematic illustration, in longitudinal cross section, of a filter-sleeve according to the invention;  
         [0019]      FIG. 2  is a schematic illustration of a filter-sleeve combined with an installation plug to bring the filter-sleeve to the repair site;  
         [0020]      FIG. 3  is a schematic perspective view illustrating the filter-sleeve combined with an installation plug, CCTV camera, and weight, being lowered into a damaged pipe;  
         [0021]      FIG. 4   a  is a schematic perspective view illustrating the filter-sleeve combined with an installation plug, placed over a damaged area;  
         [0022]      FIG. 4   b  is a schematic perspective view illustrating the filter-sleeve expanded by the installation plug and locked in place;  
         [0023]      FIG. 5   a  is a schematic perspective view illustrating the filter-sleeve installed, the installation plug with camera being lowered;  
         [0024]      FIG. 5   b  is a schematic view of the interior of the filter-sleeve showing a verification that the locks of the sleeve have been secured;  
         [0025]      FIGS. 6   a ,  6   b , and  6   c  are schematic illustrations of the relative position between the filter-sleeve and the installation plug during different phases of the method of the invention. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0026]      FIGS. 1-6  schematically illustrate an exemplary apparatus according to the invention, as well as an exemplary manner by which such apparatus can be employed in making well repairs. However, the breadth of the invention is not intended to be limited by the particular illustrations and particular descriptions of such illustrations of the exemplary embodiments described herein, and is applicable to the repair of other types of conduits and pipes, particularly underground conduits and pipes.  
         [0027]      FIG. 1  shows a filter-sleeve  1  according to the invention, in a schematic longitudinal cross section positioned within a well casing  9 , or host pipe. As seen in  FIG. 1 , the well casing  9  has a damaged area  10 , in the form of a hole, over which the filter-sleeve  1  is to be installed. Such damage can be created, for example, by electrolytic corrosion caused by the electrical current of a pump motor within the well/casing or a break caused by ground movements.  
         [0028]     The filter-sleeve includes a core  2 , that can be rolled from plain or corrugated sheet metal, such as stainless steel, plated or coated steel or plastic sheet, depending upon the chemical regime in the host casing/pipe  9 .  
         [0029]     The core  2  of the filter-sleeve  1 , which can include a plurality of drain holes  6 , is equipped with a locking arrangement, such as locks  8 , or other types of fasteners, for locking the filter-sleeve according to any of a number of patents, in the name of the inventor of the instant invention, in the technology of no-dig repair, i.e., repair of underground pipes and conduits without excavation of the site of the repair. Among such patents, the disclosures of the following of which are hereby incorporated by reference thereto in their entireties, are U.S. Pat. No. 5,119,862, U.S. Pat. No. 5,351,720, and U.S. Pat. No. 6,138,718, which disclose methods and apparatus for making such repairs, using a repair sleeve that is transported to the location of damage of a host pipe, and fixed in place with an inflatable/expandable installation plug, the plug thereafter removed from the repair site.  
         [0030]     The filter-sleeve  1  shown in  FIG. 1  preferably includes a reinforcing coiled plate  3  equipped with drain holes. This optional plate can take the form of a second core made of stainless steel, for example, which is also perforated to allow water to penetrate.  
         [0031]     The filter component of the filter-sleeve  1  shown in  FIG. 1  is made from a suitable filtering material, such as felt  5 , although such material could comprise a wire sieve, perforated sheet, or other porous material.  
         [0032]     Further, the filter-sleeve  1  shown in  FIG. 1  includes O-rings  4  or other type of support devices for the purpose of tightly fitting the filter-sleeve in the well casing  9 , or host pipe, and for the purpose of supporting the filtering material.  
         [0033]     The filter-sleeve  1  shown in  FIG. 1  also includes an optional external protective netting or mesh  7 , or other protective material.  
         [0034]     Only as an exemplary embodiment of the invention, for a host pipe/well casing  9  having an internal diameter D hp  of 15.25 inches (38.74 mm), the body of the core  2  of the filter-sleeve shown in  FIG. 1  has an outer diameter D sl , of approximately 14 inches (35.56 mm) and a length L of approximately 24 inches (60.96 mm). Obviously, however, the invention encompasses the lining and repair of pipes/casings of any size, the components of the filter-sleeves then being sized appropriately to accomplish the objectives consistent with the invention.  
         [0035]      FIG. 2  is a schematic illustration of a filter-sleeve  1  coiled down upon and securely fitted onto an inflatable installation plug  11 , thereby forming a sleeve/plug assembly which is then lowered into a well casing  9  that is in need of repair. For this purpose, the upper end  11   a  of the plug  11  is connected to a coupling  12  via chains  13  or other attachment mechanism, thereby suspending the plug  11  by means of a cable, wire, or rope, for example, from an operational/monitoring station above ground.  
         [0036]     The vertical alignment of the sleeve/plug assembly shown in  FIG. 2  is adjusted by the weight  14  attached to the bottom of the plug  11 . Also shown in  FIG. 2  are a plurality of optional safety tapes  15 , made of PVC, e.g., which are attached to the upper end of the plug  11  or to the chains  13  or cable supporting the sleeve/plug assembly, and to the interior of the filter-sleeve  1 . The function of the safety tapes  15 , if used, is explained below in connection with  FIGS. 6   a ,  6   b , and  6   c . In short, in the event the plug  11  were to lose its adherence to the filter-sleeve, the filter-sleeve can then retain its attachment to the plug  11  by being secured by the tapes  15  to the interior surface of the core of the filter-sleeve and to the top of the plug.  
         [0037]     A band of tape  16 , such as adhesive tape or other equivalent means, can be used to surround the entire assembly, at the bottom thereof as shown in  FIG. 2 , to assist in maintaining the various components of the filter-sleeve in place as the assembly is lowered into position.  
         [0038]     An air hose  17  is fitted to the sleeve/plug assembly, as shown in  FIG. 2 , for use to inflate the expandable plug  11  as needed at the site of the repair in positioning the sleeve in place. Although air pressure is preferred for this purpose, water can be used for inflating the plug. Often, the free water surface in a well can be quite deep. Just by filling the hose the necessary installation pressure is created. The only complication using water for this purpose is providing for the release of the water after the installation is completed. This can be done, however, by using a valve, such as a pipe surrounding a sleeve that is part of the aforementioned hose. The sleeve would have a hole in it. During the installation, the pipe covers the hole. When the pressure must be released, the pipe is slid upwardly letting the water escape through the hole.  
         [0039]     In  FIG. 3 , the filter-sleeve  1  and installation plug  11 , forming the aforementioned sleeve/plug assembly, with weight  14 , is shown being lowered into a damaged pipe  9 , i.e., host casing. At the top of the assembly a CCTV camera  18  is positioned for use during the positioning of the assembly within the damaged pipe and for use during the repair.  
         [0040]      FIG. 4   a  schematically illustrates the sleeve/plug assembly having been lowered and positioned in place over the damaged area  10  of the pipe  9 .  
         [0041]      FIG. 4   b  schematically illustrates the filter-sleeve  1  having been expanded, by means of the installation plug, according to methods taught by the inventor in any of the aforementioned patents, for example, to securely lock the filter-sleeve  1  in place within the pipe  9 .  
         [0042]     The protective mesh  7 , if used, protects the felt  5 , or other filtration material, during the expansion of the plug  11 . In  FIGS. 3, 4   a ,  4   b , and  5   a , the circular ribbed outer surface of the filter-sleeve is the filter felt  5 . The ribbed appearance results from the fact that the felt is soft and rests upon the aforementioned O-rings  4  shown in  FIG. 1 .  
         [0043]     As the expansion of the plug causes the filter-sleeve  1  to reach the desired diameter, the locks  8  of the sleeve (or other locking device or fasteners) are caused to engage and thereby lock the filter-sleeve in a suitable expanded diameter, as is generally known in the art, such as disclosed in the aforementioned patents. The elasticity of the O-rings, upon deflation of the plug  11 , effect the locking of the locks  8 .  
         [0044]      FIG. 5   a  schematically illustrates the filter-sleeve  1  installed within the pipe and the installation plug  11 , with camera  18 , being lowered through the interior of the filter-sleeve  1 , so that the proper engagement of the locks  8  thereof.  FIG. 5   b  illustrates the interior of the filter-sleeve, and a verification that the locks  8  along the length of the sleeve have been properly secured.  
         [0045]     At the conclusion of the installation, following the aforementioned verification that the repair has been successfully completed, the installation plug and other accessories fitted with the plug are then raised and removed from the casing/pipe  9 .  
         [0046]      FIGS. 6   a ,  6   b , and  6   c  are schematic illustrations showing the relative position between the filter-sleeve and the installation plug during different phases of the method according to the invention. Also shown in these figures is a schematic depiction of the adhesive safety tapes  15 , the use of which had been mentioned above as optional in connection with the creation of the filter-sleeve/installation plug assembly shown in  FIG. 2 .  
         [0047]     For the sake of convenience in understanding, the host pipe  9  has been omitted from  FIGS. 6   a ,  6   b , and  6   c  and reference numerals are not duplicated throughout these figures.  
         [0048]     In  FIG. 6   a , the filter-sleeve  1  and the installation plug  11  are shown in their combined position shown in  FIG. 2 . In  FIG. 6   a , however, a plurality of adhesive safety tapes  15  are shown for ensuring that the filter-sleeve  1  does not slip off of the plug in the event, as mentioned above, the assembly were to be lowered deep within a well with sufficiently low temperatures that, for this or for another reason, the sleeve  1  were to lose its adherence to the plug. As shown in this optional feature of the invention, the plurality of tapes  15  are adhered to both the interior surface of the filter-sleeve  1  and to the plug  11 . As can be seen in each of  FIGS. 6   a ,  6   b , and  6   c , the lower ends of the tapes  15  are fixed to the lower end of the plug  11 . While the filter-sleeve  1  and installation plug  11  are positioned as shown in  FIG. 6   a , of course, according to the description above, the assembly of filter-sleeve  1  and installation plug  11  is maintained as a unit by means of a slight expansion of the expandable/inflatable plug applying pressure from within the coiled sleeve  1 .  
         [0049]     After the filter-sleeve has been locked in place by the expansion of the inflatable plug  11  and the locking of the filter-sleeve against the well casing/pipe, as explained above, the deflated installation plug  11  is then lowered through the interior of the filter-sleeve  1 , as shown in  FIG. 6   b , for verifying the success of the repair by use of the CCTV camera as described above. This relative position of plug  11  and sleeve  1  shown in  FIG. 6   b  is also shown in  FIG. 5   a , although in the latter figure the tapes  15  are not shown.  
         [0050]     In  FIG. 6   a , as the filter-sleeve/plug assembly is suspended by the cable  19  and before the filter-sleeve is locked in place against the inner surface of the casing, the filter-sleeve  1  is prevented from inadvertently falling downwardly relative to the plug by virtue of the attachment of the tapes  15 . However, as shown in  FIG. 6   b , the plug  11  itself is able to be lowered relative to the installed filter-sleeve  1  for the purpose of the verification step. The lower ends of the tapes  15 , as shown in  FIG. 6   b , provide sufficient slack for this.  
         [0051]     Finally, as the installation plug  11  and other accessories fitted with the plug are raised from the casing/pipe, as shown in  FIG. 6   c  at the conclusion of the installation, the adhesive tapes  15  are peeled off of the inner surface of the installed filter-sleeve  1 .  
         [0052]     The filter-sleeve  1  of the invention forms a short single repair filter-sleeve in place. Alternatively, particularly in the case of a large damage area, or a damage area that extends along the casing/host pipe  9 , a plurality of filter-sleeves can be successively installed to thereby form a multi-filter-sleeve repair inside the casing/host pipe.  
         [0053]     After the filter-sleeve, or multi-filter-sleeve, is locked in place, the filter prevents fines and sand from entering the pipe and clean water passes through the felt, or other filtration material, and through the perforated sleeve into the pipe.  
         [0054]     Over time, the fines and sand will clog the filter. The clogged filter can then be removed, cleaned for reuse, or replaced.