Abstract:
A tank is provided, including a tray positioned on a skid; an outer tank wall positioned within the tray; an inner tank wall positioned within the first outer tank wall; wherein the outer tank walls is moveable from a first position wherein the inner tank wall is substantially contained within the outer tank wall; and a second position wherein the moveable outer tank wall is elevated, thereby increasing the height and storage capacity of the tank.

Description:
RELATED APPLICATION 
       [0001]    The present application claims the benefit of priority under 35 U.S.C. 119 to Canadian Patent Application Serial No. 2,778,306, filed May 25, 2012, and entitled “Telescopic Liquid Tank”, all of which is commonly owned herewith. 
       FIELD OF THE INVENTION 
       [0002]    The invention relates to tanks for use in fracking operations, and more particularly large volume, transportable, steel water tanks for such use. 
       BACKGROUND OF THE INVENTION 
       [0003]    Large volumes of water are required for hydraulic stimulation (referred to as fracture or fracking) of well sites. In order to store large volumes of water, either many traditional horizontal rectangular tanks, or many traditional vertical cylindrical tanks, are needed, often in conjunction with a geomembrane lined open top tank (such tanks are prone to damage and leaks). 
         [0004]    Open top tanks are large volume tanks with a large surface footprint. They are usually circular, which is an inefficient use of space. Using open top tanks requires transferring fluid from the tank to a frack tank farm for use by the fracking equipment. Open top tanks are lined with a geomembrane liner that is fragile and prone to damage and leaks. The liner is not reusable, and is expensive to replace. Specialized pumping equipment is required to use with these tanks It is difficult to safely get all of the fluid in a tank from the tank bottom, resulting in some waste. Open top tanks are expensive to clean and decommission, and can cause a major incident in the case of tank failure, as there is no secondary containment. These tanks are not compartmentalized and in case of a failure, the entire volume of water may be lost. There are also limits on the height of these tanks, resulting in large footprints as the liquid capacity per area of land is low 
         [0005]    Vertical cylindrical 400 bbl tanks are a standard oilfield tank, widely used in Canada. Volume of these tanks is normally 400 bbl, or 60 m 3 . At best, these tanks can be transported in pairs on one truck. The cylindrical tanks require elaborate manifolds and many hoses to properly connect the tanks for fracking use. As the tanks have no built in containment, the tank farm is typically bermed and lined. Matting is required underneath the tanks Matting and manifolds and hoses typically require at least one full additional truck load. The cylindrical tanks also take up a large footprint on an area/volume basis. 
         [0006]    Rectangular tanks are either mobile via an axle, or are skidded, or such tanks are widely used in the U.S. These rectangular tanks may have volumes up to 100 m 3 , although 80 m 3  is more common. These tanks have all the disadvantages of the vertical tanks, and require an even larger surface footprint. In addition, they can only be transported or moved as single tanks, which adds to the transportation and set up cost. 
         [0007]    What the current tanks used in fracking operations lack is a built in secondary containment, and integrated or compatible pumping systems, as well as a tank design that is easily transportable but also high volume. 
       SUMMARY 
       [0008]    The telescopic frack water tanks according to the invention provide large volume fluid storage, a compact footprint, with minimal transportation and installation cost. The system combines three components, namely a large volume horizontal telescopic tank that is highway transportable; has easily integrated pumping systems; and has built in secondary containment 
         [0009]    The tank according to the invention is used to support the hydraulic stimulation (fracture) of shale gas wells. A pad operation for such frac operations likely includes at least three of these tanks, each having a volume of at least 500 m 3 . A first tank serves as a primary storage/receiving tank, and supplies fluid to a second tank. The second tank is used in place of the traditional fracking tank farm and suction manifold, and the fracking equipment blender and charge pumps are tied directly into the second tank. The third tank is used for flowback storage and transfer, replacing the traditional flowback tank farm. 
         [0010]    Large volume storage is thereby realized via one transportable tank according to the invention. The tank is adjustable in height once delivered to the location, to allow for large volume capability. Setup and installation of the tank is fast, resulting in significant transportation cost savings. The incorporated containment prevents environmental spills, and the included recirculation pump transfers fluid from containment back into the tank, if necessary. The incorporated pumping systems and tank connections further increase functionality, and eliminate the need for additional equipment. Each tank can replace several standard vertical tanks, or standard horizontal tanks. 
         [0011]    A system using the tanks according to the invention is capable of transferring high volumes of water to the fracking equipment, pumping at high pressure off the pad to offsite storage, and receiving and transferring flowback water to the primary pad storage tank. In addition, pumping systems allow for fluid circulation to prevent line freeze problems, as well as circulation through a water heater. Incorporated light masts can eliminate additional surface rentals, such as light towers, and incorporated weirs allow compartment separation and can be used for sand settling, chemical injection, and other functions. 
         [0012]    A tank is provided, including: a tray positioned on a skid; a first tank wall positioned on the tray; a second inner tank wall positioned within the first inner tank wall; wherein the first tank wall is moveable from a first position wherein the second inner tank wall is substantially contained within the first tank wall; and a second position wherein said first tank wall is elevated thereby increasing the height and storage capacity of the tank. 
         [0013]    When the first tank wall is in the second position, a seal is formed between the first tank wall and the second tank wall. The first tank wall is moveable from the first position to the second position by a plurality of hydraulic rams. The tank may include a pump positioned to pump water leaking through the seal to the tray back into the tank, or to another location, such as another tank. The seal may include a gasket between a bottom inside portion of the first tank wall and a top outside portion of the second tank wall. The seal may further include a plurality of inflatable hoses positioned between the second tank wall and the first tank wall. 
         [0014]    A further tank is provided, including: a spill containment tray positioned on a skid; a first tank wall positioned on the tray; a second inner tank wall positioned within the first inner tank wall; wherein the second inner tank wall is moveable from a first position wherein the first outer tank wall substantially contains the second inner tank wall; and a second position wherein the second inner tank wall is elevated thereby increasing the height and storage capacity of the tank. 
     
    
     
       DESCRIPTION OF THE FIGURES 
         [0015]      FIG. 1  is a side view of a tank according to the invention, in a raised position. 
           [0016]      FIG. 2  is an end view thereof. 
           [0017]      FIG. 3  is an end view thereof, showing the tank in a lowered position. 
           [0018]      FIG. 4  is a top view thereof; 
           [0019]      FIGS. 5A ,  5 B,  5 C, and  5 D are cross sectional views of fastening elements and sealing elements of the tanks walls according to the invention. 
           [0020]      FIG. 6  is an end view of an alternative embodiment of the tank according to the invention. 
           [0021]      FIG. 7  is a partial cross sectional view of an alternative embodiment of a sealing element for the tank. 
           [0022]      FIG. 8  is a perspective view of a sealing member used in the sealing embodiment. 
           [0023]      FIG. 9  is a cross sectional end view of an alternative embodiment of the tank according to the invention. 
           [0024]      FIG. 10  is a cross sectional view of an embodiment of a seal therein, detailing C in  FIG. 9 . 
           [0025]      FIG. 11  is a detailed view of an embodiment of a foldable platform in the tank, detailing B in  FIG. 9 . 
           [0026]      FIG. 12A  is a sectional view taken along C-C in  FIG. 9  of an embodiment of a drip tray within the tank. 
           [0027]      FIG. 12B  is a side cross sectional view thereof, detailing A in  FIG. 9 . 
           [0028]      FIG. 13  is a perspective view of an embodiment of a tank according to the invention. 
           [0029]      FIGS. 14   a ,  14   b , and  14   c  are side cross sectional views of an alternate embodiment of the invention showing the raising of the tank wall. 
           [0030]      FIG. 15  is a top view showing the corner of an embodiment of the tank according to the invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0031]    The tank according to the invention includes horizontal tank  10 , as shown in  FIGS. 1 through 4 . Tank  10  is secured to skids  20 , and may be of the maximum (oversize) width, length, and height (when in a lowered position) permitted for travel by road. 
         [0032]    Tank  10  includes closed outer tank  30  and closed inner tank wall  40 . Inner tank wall  40  is sized to fit within outer tank  30 , and can be raised telescopically to increase the overall wall height of tank  10  and thereby the storage capacity of tank  10 . Further inner tank walls may be included in tank  10  in a nesting pattern to provide multiple telescopic interior tanks thereby providing increased height when the tank walls are raised. 
         [0033]    Inner tank wall  40  is raised using a plurality of hydraulic lifts  50 , positioned around the exterior wall  60  of outer tank  30 . In a typical embodiment of the invention, six or more lifts  50  would be present to allow for even lifting of inner tank wall  40 .  FIGS. 1 and 2  shows inner tank wall  40  in a raised position. 
         [0034]    As shown in  FIGS. 5A through 5D , interior tank wall  40  creates a seal with the adjacent exterior wall  60  when the hydraulic lifts are fully extended, and pressure is forced upon opposite faces of wall  40  and wall  60 .  FIGS. 5A through 5D  each represent an alternative sealing means. Additional sealing is provided by grease injection and gasket material  55  between inner tank wall  40  and exterior wall  60 . Grease injection nipples  45  may be positioned at regular intervals to allow grease injection. 
         [0035]    As seen in  FIG. 5A , projection  100 , at the bottom and outside of interior tank wall  40 , is sized to fit indentation  110  at the top and inside of exterior wall  60 . Gasket material  55  is positioned between projection  100  and indentation  110 . 
         [0036]    An alternative embodiment of sealing means is shown in  FIG. 5B , in which mating projection  120  at the bottom outside edge of interior tank wall  40  meets the inner edge of mating projection  130  at the top inside edge of exterior tank wall  60  to form a seal. Gasket material  55  is positioned between projections  120 ,  130 . 
         [0037]      FIG. 5C  shows another embodiment of sealing means, wherein dividers  140  at the bottom of inner tank wall  40  form channels  150 . Inflatable rubber hoses  160  run through each channel  150 , and are inflated when the inner tank wall  40  is raised. Between each rubber hose  160  and exterior wall  60  are rubber sealing gaskets  170 . 
         [0038]      FIG. 5D  shows yet a further embodiment of sealing means, in which gasket  55  on pivotable member  180 , is positionable under inner tank wall  40 , after inner tank wall  40  has been raised. Inner tank wall  40  is then sealed using gravity as inner tank wall  40  rests on pivotable member  180  which pivots on hinge  185 . 
         [0039]    Containment tray  70  is positioned around the base  80  of exterior tank wall  60  to contain any leakage that may slip through the seals at the junction of interior tank wall  40  and exterior wall  60 . A built in transfer pump (not shown) may be present to transfer any fluid collected in the containment tray back into the main tank  10 . 
         [0040]    Exterior wall  60  includes a plurality of flanged and valved connection ports (not shown) to allow for liquid transfer from the tank and reception of liquids from other sources. 
         [0041]      FIG. 6  shows an alternative embodiment of tank  10  in which outer wall  200  is raise by hydraulic lifts  50  relative to inner wall  210 . An example of sealing means for this embodiment is shown in  FIG. 7 , in which inward extension  220  at the bottom of outer wall  200  meets outer facing extension  230  of inner wall  210 . Rubber inflatable seal members  240 , as shown in  FIG. 8 , may be positioned on either inward extension  220  or outward extension  230  facing the other extension. When the rubber seal members  240  meet inward extension  220 , members  240  flatten, and may be inflated by air or liquid, creating a seal between inner wall  210  and outer wall  200 . 
         [0042]    Tank floor  90  may be gently sloped and have a liquid outlet at the base  80  to allow for ease of extraction of the liquid therein. Built in pumping systems (not shown) may be present to allow transfer of liquid between tanks  10 , transfer of liquid off site, and circulation of liquid through heaters and pipelines to prevent freezing. Alternatively, the pumping systems may be positioned nearby tank  10 , and in liquid communication with tank  10  via hoses and the like. 
         [0043]    When fracking job is finished, tank  10  is drained, inner tank wall  40  (or outer tank wall  200 ) is lowered to transport height, and tank  10  is winched onto standard high-bed tractor trailer, and can be moved from the site. Typical volume of tank  10  would be 500 m 3 , based on a two tier tank wall design. 
         [0044]      FIG. 9  shows a side cross sectional view of another embodiment of a tank  10  according to the invention. In this embodiment of tank  10 , outer wall  200  is elevatable. Foldable walking platform  215  is positioned around the interior of inner tank wall  210  to allow users access to tank  10 , Outer wall  200  is shown in elevated position in dashed lines, and in unelevated position in solid lines. 
         [0045]      FIG. 10  is a detailed view of C in  FIG. 9 , showing the sealing means. Guide  310  acts as a pinning plate to guide walls  200  and  210  into position. Pins  315  are then used to secure walls  200  and  210 , by passing pins  315 ,  316  through aligned apertures (not shown) in each wall  200 ,  210 . Pin  315  may be fixed in place while pin  316  is removable to allow outer wall  200  to be elevated or lowered. Seal members  240  are secured to the top of inner wall by screws or the like. 
         [0046]      FIG. 11  shows a detailed view of B in  FIG. 9 , showing base  325  of walking platform  215  secured to inner wall  210 . 
         [0047]      FIG. 12A  is a cross sectional top view of elevated outer wall  200  showing links  360 . Links  360  are secured to outer wall  200  by pins  315 ,  316 . 
         [0048]      FIG. 12B  is a detail of A showing the bottom portion of inner wall  210  and outer wall  200 . Drip tray  330  provides secondary liquid containment and has lip  335  extending outwardly from outer wall  200 . 
         [0049]      FIG. 13  is a perspective view of tank  10  showing the frame of the inner wall  210  and outer wall  200 . Extension  400  provides support and stability to tank  10 . Pipes  410  allow for intake or removal of water or another fluid. Ladder  420  allows workers to reach the bottom of tank  10 . 
         [0050]    The bottom of tank  10  is supported by bottom cross beams  430 . Support beams  440  extend vertically to support inner tank wall  210 . Door  450  allows access to the interior of tank  10 , for cleaning, or for a vacuum truck operator. Door  450  may be configured so that it cannot be opened when tank  10  is full to provide safety for workers nearby. 
         [0051]    Outer wall  200  is supported vertically by vertical support beams  460  and upper horizontal cross members  470  and lower horizontal cross members  480 . Upper frame member  490  maintains the shape of outer wall  200 . Tank  10  is generally made of steel, with the exterior of outer wall  200  painted and the interior of inner wall  210  having an anti-corrosion coating. 
         [0052]    Ring  500  surrounds the top of inner wall  210 . Links  360  extend upwardly from ring  500 . Attached to support beams  440  is walking platform  215 . 
         [0053]      FIGS. 14A ,  14 B and  14 C show the process by which outer wall  200  raises.  FIG. 14A  shows outer wall in an unelevated state. Guide  860 , which may be a pipe, has a links  890  at the top and bottom to allow it to be secured to or detached from wall  200 . Wall  200  is positioned in-between guide  860  and guide  880 , and is secured to hydraulic lift  338 . Guide  880  is extendible and may rise with lift  338 . The lower end of guide  880  is fixed in position. 
         [0054]      FIG. 15  shows gusset  390  which is used by hydraulic lift  338  to raise wall  200 . Guides  860  and  880  are on opposite sides of wall  200 . Corners of tank  10  are cured to correspond to the bending of seals  240 , which may not always permit a square corner. 
         [0055]    When inner wall  210  and outer wall  200  are pinned together (i.e. the elevatable wall is not in an elevated position and the walls  200 .  210  are secured by pins), hydraulic lift  338  can expand freely downward and act as a jack to lift the entire tank structure  10 , as shown in  FIG. 14B . This is used for loading and unloading tank  10  onto a trailer. The hydraulic lifts elevate tank  10  so that a trailer can be positioned underneath it. 
         [0056]    Hydraulic lifts  50  also lift outer wall  200  from the inner wall  210 . After tank  10  is unloaded, it is lowered to the ground. The two walls  200 ,  210  are now unpinned. Now when the hydraulic lifts  50  jacks extend, they lift outer wall  200  and separate the two walls  200 ,  210 . 
         [0057]    The above-described embodiments have been provided as examples, for clarity in understanding the invention. A person with skill in the art will recognize that alterations, modifications and variations may be effected to the embodiments described above while remaining within the scope of the invention as defined by claims appended hereto.