Patent Publication Number: US-2015076142-A1

Title: Portable tank, and method of assembling a tank at a well site

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of U.S. Application No. 61/879,067, filed Sep. 17, 2013, and which is incorporated herein by reference in its entirety. 
    
    
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
     Not applicable. 
     THE NAMES OF THE PARTIES TO A JOINT RESEARCH AGREEMENT 
     Not applicable. 
     BACKGROUND OF THE INVENTION 
     This section is intended to introduce various aspects of the art, which may be associated with exemplary embodiments of the present disclosure. This discussion is believed to assist in providing a framework to facilitate a better understanding of particular aspects of the present disclosure. Accordingly, it should be understood that this section should be read in this light, and not necessarily as admissions of prior art. 
     FIELD OF THE INVENTION 
     The present inventive concept relates to the field of hydrocarbon recovery operations. More particularly, the invention relates to a tank that is designed to hold a large volume of hydraulic fracturing fluid, wherein the tank may be assembled at a well site and then broken down and transported away when a hydraulic fracturing operation is completed. 
     TECHNOLOGY IN THE FIELD OF THE INVENTION 
     Hydraulic fracturing is the parting of a deep subsurface rock matrix through the injection of a pressurized liquid. Hydraulic fracturing typically consists of injecting water (or brine) with friction reducers into a formation at such high pressures and rates that the reservoir rock parts and forms a network of fractures. In some cases, viscous fluids such as shear thinning, non-Newtonian gels or emulsions are used, either in addition to or instead of an aqueous fluid. 
     The fracturing fluid is typically mixed with a proppant material such as sand, crushed granite, ceramic beads, aluminum oxide, or other granular materials. The proppant serves to hold the fracture(s) open after the hydraulic pressures are released. Fractures help valuable hydrocarbon fluids migrate towards the wellbore. In some cases, fractures may be as small as one mm in width, with the width being sustained by the proppant material. 
     The process of hydraulic fracturing is sometimes referred to as hydro-fracturing, or just fracking. The technique has become common in wellbore completions in North America, particularly for extended-length, horizontally-completed wells in shale gas, tight gas, tight oil, and coal seam gas formations. 
     Fracking is typically done prior to placing a well on-line for production. However, in some instances, a formation fracturing operation may be conducted as part of a stimulation procedure during the life of the well. 
     Fracking operations require large volumes of water. As fracking sites are often very remote, portable tanks may be used to provide the required amount of water on-site during fracking operations. There is a need to provide portable tanks that are easily transported to a fracking site and readily assembled at the site. The present application relates to a portable water tank which may be transported to and assembled at the site of a remote hydraulic fracturing operation. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       So that the manner in which the present application can be better understood, certain illustrations and figures are appended hereto. It is to be noted, however, that the drawings illustrate only selected embodiments and elements of a portable tank and are therefore not to be considered limiting in scope for the portable tank as described herein may admit to other equally effective embodiments and applications. 
         FIG. 1  is a perspective view of an assembled portable tank of the present invention, in one embodiment. 
         FIG. 2  is a portion of the assembled tank of  FIG. 1 . Four panel sections are visible, with the panels being stacked to form two levels. 
         FIG. 3  is a close-up side view of a jaw connector securing an upper panel to a lower panel, in one arrangement. 
         FIG. 4  is a perspective view of a first end of a tank panel of the present invention, in one embodiment. 
         FIG. 5  is a perspective view of a second end of a tank panel of the present invention, in one embodiment. 
         FIG. 6  is an enlarged view of the second end of a tank panel of  FIG. 5 . 
         FIG. 7  is front view of a tensioning system used for securing laterally adjoining panels of an assembled tank, in one embodiment. 
         FIG. 8  is a perspective view of the tensioning system of  FIG. 7 . 
         FIG. 9  is another perspective view of the tensioning system of  FIG. 7 . 
         FIG. 10  is a cross-sectional view of the tensioning system of  FIG. 7 , taken along line D-D. 
         FIG. 11  is another cross-sectional view of the tensioning system of  FIG. 7 , taken along line d-d of  FIG. 10 . 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  presents a perspective view of a tank  100  of the present invention, in one embodiment. The tank  100  is shown in its assembled form. The assembled tank  100  features an upper ring  110  and a lower ring  112 , representing upper and lower levels of the tank  100 . The upper ring  110  comprises a series of arcuate upper panels that are coupled through the use of a novel tensioning system (shown at  700  and described below in connection with  FIGS. 7 through 11 ). Upper panels  102  and  104  are examples of laterally adjoining panels held together through the tensioning system  700 . 
     The lower ring  112  also comprises a series of arcuate lower panels. These panels are also coupled together using the tensioning system  700  to form the lower level. Lower panels  106  and  108  are examples of laterally adjoining panels held together through the tensioning system  700 . 
     Each of the panels  102 ,  104 ,  106 ,  108 , etc. spans approximately 8 feet from top to bottom. Further, each of the panels  102 ,  104 ,  106 ,  108 , etc. is approximately 31 feet in length. Of course, it is understood that other dimensions may be adopted depending on the volume of fracturing fluid to be held in the tank  100 . The upper ring  110  sits atop and is secured to the lower ring  112  to form an assembled tank  100  with a height of approximately  16  feet. 
     Under one embodiment, both the upper ring  110  and the lower ring  112  comprises  14  panels. The respective panels of the upper  110  and lower  112  rings may be either aligned or offset. Under this embodiment, the assembled tank  100  provides a tank fill height of 16 feet with a tank diameter of approximately 138 feet. The upper  110  and the lower  112  ring panels comprise structural steel but may also comprise other material sufficiently strong to withstand burst and hoop forces applied against the ring panels and connecting elements when the tank  100  is filled with aqueous fluid. Such tank may be filled to hold approximately 1.79 million gallons of water or other liquid. Such large fluid volumes are increasingly necessary at well sites having horizontally-oriented wellbores in excess of 1,500 feet, or even in excess of 5,000 feet. Those of ordinary skill in the art will appreciate that extended-reach wellbores are completed in stages, with each stage involving the injection of many thousands of gallons of fluid to fracture incremental portions of the formation. 
     Alternative embodiments of the portable tank include variable upper panel, lower panel and assembled tank heights. As one example, upper  110  and lower  112  rings may each comprise 10 panels. Such panels may span approximately 8 feet in height from top to bottom and may be approximately 30 feet, 2 inches in length. Such embodiment results in a tank diameter of approximately 96 feet. As another example, upper  110  and lower  112  rings may each comprise 18 panels. Such panels may span approximately 8 feet in height from top to bottom and may be approximately 29 feet, 8 inches in length. Such embodiment results in a tank diameter of approximately 170 feet. 
       FIG. 2  shows a portion of an assembled tank  100  including two upper panels  202 ,  204  and two lower panels  206 ,  208 . Upper panels  202 ,  204  reside upon and are secured to corresponding lower panels  206 ,  208 . The upper panels  202 ,  204  are secured to the lower panels  206 ,  208  using respective jaw connectors  210 ,  212  and  214 ,  216  in a manner already described in U.S. Application No. 61/879,067, filed Sep. 17, 2013, which is incorporated herein by reference in its entirety. 
       FIG. 3  shows a side view of jaw connector  210  of  FIG. 2 . Jaw connector  210  is affixed to reinforcement rib  244 . As seen in  FIG. 2 , an upper portion of the lower panel  206  features a ledge  242 . The ledge  242  is disposed circumferentially along the upper portion of the lower panel  206 . A lower portion of the upper panel  202  features a corresponding ledge  240 . The ledge  240  is disposed circumferentially along the lower portion of the upper panel  202 . As seen in  FIG. 3 , the upper panel ledge  240  sits upon the lower panel ledge  242  thereby coupling the panels  202 ,  206 . 
     A jaw connector  210  secures the upper  202  panel to the lower panel  206 . A bottom portion  260  of the jaw connector  210  is affixed to the lower panel  206  at reinforcement rib  244 . In coupling the upper panel  202  with the lower panel  206 , an upper portion  270  of the jaw connector  210  is placed upon the upper panel ledge  240 . When the bolts of the jaw connector  210  are secured, the jaw connector  210  serves to bind the upper panel  202  to the lower panel  206 . The jaw connector  210  may be used at one or multiple locations along the periphery of the upper-lower ring coupling as required to secure the upper panels to corresponding lower panels. 
     Referring again to  FIG. 2 , upper panel  202  features first end  202 A and second end  202 B. Upper panel  204  features a first end  204 A and a second end  204 B. Lower panel  206  features a first end  206 A and a second end  206 B. Lower panel  208  features first end  208 A and second end  208 B. Upper panel  202  is coupled to upper panel  204  at coupling point comprising  202 B,  204 A. Lower panel  206  is coupled to lower panel  208  at coupling point comprising  206 B,  208 A. Note that upper and lower panels are substantially the same with the exception that lower panels include optional vertical reinforcing ribs (see  FIG. 2 ,  244 ). 
     As already mentioned above, upper panels and lower panels shown in  FIG. 1  and  FIG. 2  comprise structural steel. Further, each such panel is welded to a tank liner or tank wall (hereinafter referred to as simply the liner). Such liner comprises steel skin.  FIGS. 8 and 9  show upper panel  202  welded to liner  540  and upper panel  204  welded to liner  440 . Under one embodiment, a panel may also include a reinforcement liner.  FIGS. 8 and 9  show that upper panel  202  is welded to liner  540 , which is then further welded to reinforcement liner  570 . It should be noted that any upper or lower panel (or any combination thereof) may include an additional reinforcement liner depending upon the structural requirements of a tank deployment. 
       FIG. 4  shows the first end  204 A of upper panel  204 . The first end  204 A comprises a series of longitudinally disposed T-shaped connecting plates  404 ,  406 .  FIG. 4  also shows tension plates  408 ,  410 .  FIG. 8  shows tension plate  408  in greater detail. With reference to  FIGS. 4 and 8  together, the tension plate  408  comprises a first tension plate  422  and a second tension plate  420 . A first tension plate  422  is affixed to an outer edge of a connecting plate  404  and extends outward in a direction perpendicular to the connecting plate  404 . A second tension plate  420  is affixed to both the connecting plate  404  and first tension plate  422  and occupies a plane orthogonal to both the connecting plate  404  and the first tension plate  422 . 
       FIG. 5  shows the second end  202 B of the upper panel  202 . The second end  202 B includes a series of longitudinally disposed T-shaped receiving plates  502 ,  504 ,  506 ,  508 . The receiving plates  502 ,  504 ,  506 ,  508  (as part of upper panel  202 ) are affixed to liner surface  540 . The receiving plates  502 ,  504 ,  506 ,  508  and liner surface  540  provide receiving cavities  542 ,  544  for receiving connecting plates  404 ,  406 .  FIGS. 5 and 6  also show vertically disposed locking plates  550 ,  552  affixed to receiving plates  506 ,  508 . As one example,  FIGS. 5 and 6  show the vertically disposed locking plates  550 ,  552  affixed to receiving plates  506 ,  508 . The locking plates  550 ,  552  and receiving plates  506 ,  508  form slots (or shoulders) for receiving and securing corresponding corners of connecting plates. 
     Referring to  FIGS. 4 ,  5 , and  6  together, slots/shoulders  554  and  556  receive corresponding corners  454  and  456  of connecting plate  406  when panels  202  and  204  are secured to one another as further described below. It should be noted that all first end connecting plates and second end receiving plates interlock in this manner when panels  202  and  204  are secured to each other. 
       FIG. 5  also shows tensioning components which function to secure panel  202  and  204 . The tensioning components are coupled to panel  202  and include a guide plate  562 , tensioning screw  564 , and locking wedge manipulator  568 . The tensioning components cooperate with tension plate  408  coupled to panel  204  ( FIG. 4 ) to form a tensioning system  700  which secures panels  202  and  204  together.  FIG. 7  shows functional operation of guide plate  562 , tensioning screw  564 , locking wedge manipulator  568  and tension plate  408  in a secured configuration. 
       FIGS. 8 and 9  show guide plate  562 , tensioning screw  564 , locking wedge manipulator  568  and tension plate  408  in greater detail. The operation of such tensioning system  700  is described herein with respect to panels  202  and  204  (and corresponding connecting plate  404  and receiving plates  502 ,  504 ). However, it should be understood that the described tensioning system  700  functions in substantially the same manner in securing any two panels of an assembled tank  100 . 
     With reference to  FIGS. 8 and 9 , an installer secures panels  202  and  204  together by manipulating connecting plate  404  into cavity  542  (see also  FIG. 5 ) formed in receiving plates  502 ,  504 . The installer may use pry bars (not shown) in combination with tensioning screw  564  to slide connecting plate  404  under corresponding locking plates  554 ,  556  until connecting plate  404  securely opposes receiving plates  502 ,  504  in slots/shoulders (not shown) under corresponding locking plates  554 ,  556  of receiving plates  502 ,  504 . The installer turns tensioning screw  564  to increase pressure on second tension plate  422  to secure connecting plate  404  under corresponding locking plates  554 ,  556 . 
     Continuing with reference to  FIGS. 8 and 9 , the installer may then insert the locking wedge manipulator  568  into dish  570  positioned below tension plate  408 . The locking wedge manipulator  568  is coupled to locking wedge  572 . The locking wedge comprises a finger  574  (see  FIG. 11 ) which resides between receiving plate  502  and connecting plate  404  in order to ensure that connecting plate  404  maintains its position under locking plates  554 ,  556 . 
       FIG. 10  is a cross-sectional view of the tensioning system  700  of  FIG. 7 , taken along line D-D of  FIG. 7 .  FIG. 10  shows locking plate  554  affixed to receiving plate  502 , and locking plate  556  affixed to receiving plate  504 .  FIG. 10  also shows the locking wedge manipulator  568  coupled to locking wedge  572 .  FIG. 10  also shows connecting plate  404 . 
       FIG. 11  is a cross section view of the tensioning system  700  of  FIG. 10 , taken along line d-d of  FIG. 10 .  FIG. 11  shows connecting plate  404 .  FIG. 11  shows locking plate  556  affixed to connecting plate  504 .  FIG. 11  shows guide plate  562 .  FIG. 11  also shows the locking wedge manipulator  568  coupled to locking wedge  572  residing in dish  570 . The locking wedge  572  is coupled to finger  574 . 
     The portable tank assembly  100  as seen in  FIG. 1  enables a large-volume tank to be transported to a remote well site via over-the-road trailer. As described herein, the upper ring comprises a series of panels and the lower ring also comprises a series of panels, forming two levels. The disassembled upper ring panels and lower ring panels may be transported in sections to the well site. A tarp is placed on a cleared location where assembly begins. The lower panel segments are assembled end-to-end using the novel coupling system described herein. The assembled lower panels comprise the lower ring. Once the lower ring is in place, the first upper panel is coupled to the lower ring using one or more jaw connectors. Once the first upper panel is in place, upper panels are installed one by one using the novel couplings system described herein whereby each upper panel is also coupled to the lower ring using one or more jaw connectors. When the tank is assembled, the tarp may be folded up and over the outer periphery of the tank and circumferentially coupled to the upper end of the upper ring. The tank (as shown and described with respect to  FIG. 1 ) may be filled to hold approximately 1.79 million gallons of water or other liquid in one embodiment, but embodiments are not so limited. When the tank is drained of water in connection with a hydro-fracturing operation, it may be disassembled by simply reversing the above described process. The tank panels and hardware may then be loaded onto a trailer and transported from the well site. 
     The portable tank is of course not limited to use at a well site. The portable tank may be used at other locations where there is a need to hold large volumes of water. As one example, the portable tanks may be transported to and assembled at flood locations to provide temporary storage of flood waters. The portable tanks may also be used at water recycling locations, e.g. at locations where large volumes of water previously used in fracking operations are recycled. Firefighting operations in remote locations may trigger a need for mobile and rapidly deployable water storage capabilities during firefighting operations. The portable tank components provide mobile and high capacity water storage capabilities and may be deployed at any location where there is an need to hold water in tanks or holding vessels. 
     A method for fabricating a water tank is also provided herein. In one aspect, the method first comprises removing a plurality of arcuate tank panels from the bed of a trailer. Each panel has a length A−B according to the formula: 
         A−B= ( D×π )/ n   1            wherein: D=Diameter of the tank; and    n 1 =number of panels.       
     Each panel has a first end and a second opposing end. The first end of each panel is configured to interlock with the second end of an adjoining panel. Each panel further comprises a liner. The liner is affixed along an inner surface of each arcuate tank panel and has a first end and a second end. The first end of each liner resides intermediate the first and second ends of an associated tank panel, while the second end extends beyond the second end of the associated tank panel. 
     The method also includes interlocking adjoining tank panels to form a cylindrical container having an open top. The interlocking step may be performed by using the tensioning system described herein. The method further includes mechanically compressing adjoining tank sections so that adjoining tank panels further form a fluidically-sealed container. 
     In one aspect, A−B is at least 28 feet in length and at least 5 feet in height. In a preferred embodiment, the water tank comprises a first level of arcuate tank panels, with each panel having a length A−B, and a second level of arcuate tank panels residing on the second level of arcuate tank panels. Optionally, each panel in the second level of tank panels also has a length A−B. Alternatively, each panel in the second level of tank panels has a length C−D according to the formula: 
         C−D= ( D×π )/ n   2            wherein: D=Diameter of the tank; and    n 2 =number of panels in the second level.       
     Under an embodiment, each panel fabricated from one or more of a metallic and polycarbonate material, and each liner is fabricated from one or more of a metallic and polycarbonate material. 
     Under an embodiment, the first end of each panel comprises a series of vertically disposed connectors, and the second end of each panel comprises a series of vertically disposed connectors configured to mate with the connectors at the first end of an adjoining panel. 
     Under an embodiment, at least some of the connectors at the first end of each panel and the mating connectors at the second end of each panel are (i) T-shaped, (ii) circular-shaped, or (iii) combinations thereof. 
     Under an embodiment, the second end of each panel comprises one or more guide plates extending transverse from an outer surface of the panel, each second end guide plate having a through-opening, the first end of each panel comprises one or more tension plates extending transverse from an outer surface of the panel. 
     Under an embodiment, the method further comprises running a bolt through the through-opening, wherein the mechanically compressing adjoining tank sections comprises rotating the bolt. 
     Under an embodiment, at least two of the connectors at the second end of each panel comprises a locking plate, each locking plate residing on an outer surface of an associated connector and providing a shoulder that contacts a mating connector on the first end of an adjoining panel. 
     Under an embodiment, the second end of each panel further comprises one or more locking wedge plates extending transverse from an outer surface of the panel and residing below the one or more tension plates at a first end of an interlocked panel. 
     Under an embodiment, the method comprises placing the one or more locking wedge plates in a dish residing beneath the one or more tension plates. 
     Under one embodiment, a water tank comprises a plurality of arcuate tank panels, each panel having a length A−B according to the formula: 
         A−B =( D ×π)/ n   1  
         wherein: D=Diameter of the tank    n 1 =number of panels.       

     Under an embodiment each panel has a first end and a second opposing end, with the first end of each panel configured to interlock with the second end of an adjoining panel; each panel further comprises a liner, the liner affixed along an inner surface of each arcuate tank panel and having a first end and a second end, wherein the first end of each liner resides intermediate the first and second ends of an associated tank panel, and the second end extends beyond the second end of the associated tank panel; and the first end and the second opposing end of each panel including tensioning components configured to mechanically compress the interlocked adjoining panels to form a fluidically sealed cylindrical container having an open top. 
     Under an embodiment, the first end of each panel comprises a series of vertically disposed connectors, the second end of each panel comprises a series of vertically disposed connectors configured to mate with the connectors at the first end of an adjoining panel, wherein at least some of the connectors at the first end of each panel and the mating connectors at the second end of each panel are (i) T-shaped, (ii) circular-shaped, or (iii) combinations thereof. 
     Under an embodiment, the second end of each panel comprises one or more guide plates extending transverse from an outer surface of the panel, each second end guide plate having a through-opening. The first end of each panel comprises one or more tension plates extending transverse from an outer surface of the panel, wherein the one or more guide plates are configured to receive a bolt through the through opening, wherein the one or more tension plates are configured to oppose the bolt, wherein the tensioning components are operable to mechanically compress adjoining tank sections by rotating the bolt, the tensioning components including the one or more guide plates and the one or more tension plates. 
     Under an embodiment, at least two of the connectors at the second end of each panel comprises a locking plate, each locking plate residing on an outer surface of an associated connector and providing a shoulder that contacts a mating connector on the first end of an adjoining panel. 
     Under an embodiment, the second end of each panel further comprises one or more locking wedge plates extending transverse from an outer surface of the panel and residing below the one or more tension plates at a first end of an interlocked panel, wherein the one or more locking wedge plates reside within a dish of the one or more guide plates, the one or more locking wedges including a portion that resides between the first end and the second end connectors to maintain the mechanically compressed configuration of the interlocking adjoining panels. 
     It is understood that the portable tank of  FIG. 1  and the method for assembling the tank are merely illustrative. Other arrangements may be employed in accordance the embodiments set forth below. Further, variations of the portable tank may comply with the spirit of the embodiments set forth herein.