Abstract:
An intermodal container for transporting frac proppant, such as frac sand, and/or other types of granular material is disclosed. The intermodal container is designed to receive frac sand from a quarry or other frac sand supply source. Once the container is filled with material, the container is loaded onto a transportation device and transported to a well site. Once received at the well site, the containers can be stacked and the frac sand stored until needed. Once the frac sand is needed, the containers are placed on a base unit and the container discharges its contents onto a conveying system formed as part of the base unit. The conveying system directs the frac sand to a blending location. The empty intermodal containers can be removed from the base unit and loaded onto a transportation device to be refilled at a mine site.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    The present application is based on and claims priority to U.S. Provisional Patent Application Ser. No. 61/811,493 filed Apr. 12, 2013. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The present disclosure generally relates to an intermodal container and base unit having a conveyor for transporting, storing and distributing a frac proppant, such as sand, from a product source to a well site. The intermodal containers and base unit allow a relatively large volume of frac proppant to be stored at a transport terminal or well site and subsequently distributed for use in hydraulic fracturing (herein abbreviated “fracking”). 
       BACKGROUND 
       [0003]    At a fracking well site, a granular-containing fluid is pumped through a well bore and to targeted regions to create “fractures” within the underlying hydrocarbon formations. The granular material used in the mining fluid is referred to as a proppant. In many cases, the proppant is a specialized type of sand (natural, man-made or modified), referred to generally as frac sand. 
         [0004]    Frac sand must be transported to the well site, which is often a significant distance away from the source of the fracking sand. Presently, the frac sand is trucked to the well site and discharged from the storage truck into a relatively small storage area at the well site. Since large volumes of sand and water must be continuously provided to the well site by trucks, traffic issues arise, which can interrupt the supply of either the water or frac sand. If the supply of either the water or frac sand is disturbed, such a disruption can result in the inefficient use of the well drilling equipment. If well drilling equipment is shut down because of the lack of supply of either sand or water, the cost to the well drilling company can be significant. 
       SUMMARY 
       [0005]    The present disclosure relates to a system and method to provide complete proppant storage, transloading and well pad delivery within unitized intermodal containers. The system and method utilizes an intermodal container that receives a granular material, such as frac sand, from an excavation site. Once the intermodal containers are loaded with frac sand, the containers may be transported to a transloading terminal using ships, rail cars or trailer trucks, or a combination of the three. When the intermodal containers are received at the well site loaded with frac sand, the containers are stacked in a storage location on or near the well site. This allows the well site operator to store sand in the same intermodal containers that were used to transport the sand to the well site. 
         [0006]    As needed, the intermodal containers are positioned on a base unit and the contents of the intermodal container are emptied onto a conveyor belt supported below a support frame of the base unit. Each of the intermodal containers is designed such that the container can empty the entire contents of the container onto the conveyor belt within approximately five minutes. 
         [0007]    Once the container has been emptied of its contents, the container is removed from the base unit and either returned to the storage location or placed on a transportation device, such as a trailer truck, for removal from the well site. The intermodal containers will typically be returned to the proppant source for refilling and retransportation back to the well site. The proppant source could be a mine or other locations that include a supply of the proppant, such as a terminal silo, sea port or other storage location. 
         [0008]    The base unit that supports multiple containers allows the containers to be emptied onto a conveyor belt such that the conveyor belt can distribute the frac sand to a blending location. The base unit remains in a fixed position and the series of intermodal containers are placed on the base unit to deliver the frac sand as desired 
         [0009]    As can be understood by the above description, the same intermodal container is used to receive sand at the sand mine, transport the sand to the well site either on a rail car, ship or truck, store the sand at the well site until the contents of the container are needed and finally discharge the sand onto a conveying system. The use of a single container for initial loading, transportation, storage and discharge reduces the amount of time and transportation cost needed to deliver frac sand to a well site. 
         [0010]    Various other features, objects and advantages of the invention will be made apparent from the following description taken together with the drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]    The drawings illustrate the best mode presently contemplated of carrying out the disclosure. In the drawings: 
           [0012]      FIG. 1  is a perspective view of a well site including a storage location having a series of stacked intermodal containers and two discharging locations in which the frac sand from the intermodal containers is discharged; 
           [0013]      FIG. 2  is a perspective view of two rows of intermodal containers supported on a base unit including a conveyor belt; 
           [0014]      FIG. 3  is a top perspective view of one of the intermodal containers including a closed top hatch; 
           [0015]      FIG. 4  is a top perspective view similar to  FIG. 3  with the top hatch open; 
           [0016]      FIG. 5  is a side, top perspective view illustrating the opening of a load door for loading of the intermodal container; 
           [0017]      FIG. 6  is a magnified view showing the operation of the manual slide gate for the intermodal container; 
           [0018]      FIG. 7  is a front view of the intermodal container; 
           [0019]      FIG. 8  is a side view of the intermodal container; 
           [0020]      FIG. 9  is a top perspective view of the base unit; 
           [0021]      FIG. 10  is a magnified side view showing the orientation of a clam shell gate; 
           [0022]      FIG. 11  is an end view of the base unit; 
           [0023]      FIG. 12  illustrates the positioning of multiple containers on a rail car; 
           [0024]      FIG. 13  illustrates the positioning of multiple containers on a trailer; 
           [0025]      FIG. 14  illustrates the stacking of multiple containers by forklift or similar equipment; 
           [0026]      FIG. 15  illustrates the transportation of empty intermodal containers utilizing a truck and trailer; and 
           [0027]      FIG. 16  is a schematic illustration of a control system for the actuators and the base unit. 
       
    
    
     DETAILED DESCRIPTION 
       [0028]      FIG. 1  illustrates a well site  10  that includes a well pad  12 . The well pad  12  includes a blender  14  that receives the supply of proppant, such as frac sand, which is then combined with water and distributed through the well bore to carry out the fracking process. Throughout the present disclosure, the term “frac sand” will be used to generally refer to various types of frac proppants, which may include sand, resin coated sand, ceramic sand and yet to be developed proppant materials. 
         [0029]    In accordance with the present disclosure, a relatively large number of intermodal containers  16  can be stacked on rig mats in a storage location  18  on the well pad  12 . In the embodiment shown in  FIG. 1 , the storage location  18  includes twelve rows of intermodal containers  16  stacked four deep and two high, which results in  96  individual intermodal containers  16  being contained at the storage location  18 . A forklift  20  or other similar device can be used to transport each of the individual intermodal containers  16  from the storage location  18  to one of two discharge locations  22  also on the well pad. Each of the discharge locations  22  feeds a conveyor  24  that receives the frac sand from a base unit  26  to supply the frac sand to the blender  14 . In the embodiment shown in  FIG. 1 , each base unit  26  is located in a fixed position and is sized to support five individual intermodal containers  16  on a first level and possibly another five intermodal containers  16  on a second level. Thus, ten of the intermodal containers  16  can be supported by each of the base units  26 . 
         [0030]    Once any one of the intermodal containers  16  has been emptied, the forklift  20  removes the container  16  from the base unit and places the empty container either back in the storage location  18  or onto the trailer/transportation truck  28 . Although ninety six containers  16  are shown in the storage area  18 , it should be understood that the number of storage containers contained in the storage area  18  could be expanded, depending upon the area available at the well site. 
         [0031]      FIG. 2  is a perspective view of the base unit  26  with seven individual intermodal containers  16  supported by the base unit  26 , five in a first row and two in an upper, second row. The base unit  26  includes a series of stabilizer legs  30  that can be hydraulically adjusted to compensate for uneven ground. Each stabilizer leg  30  includes a base  31  that moves relative to a steel base  32 . The base unit  26  supports an upper and lower run of a conveyor belt (not shown) to transport the discharged frac sand along the length of the base unit  26  from a first end  33  to a second, discharge end  34 . The base unit  26  includes a series of lower support brackets  36  that support the upper run of the moving conveyor belt that directs the frac sand to the discharge end  34 . The discharge end  34  includes a pair of support arms  38  that are angled upward to direct the flow of material to the blender, as illustrated in  FIG. 1 . 
         [0032]    Referring back to  FIG. 2 , the base unit  26  is shown in the illustrated embodiment as supporting five individual intermodal containers  16  on a first row and a possible five additional intermodal containers on a second, upper row. When two rows of intermodal containers  16  are stacked as shown in  FIG. 2 , the upper intermodal containers  16  feed material into the lower intermodal containers. The lower intermodal containers are each aligned with one of five discharge chutes  40  that are selectively controlled to discharge material from the lower intermodal container  16  onto the moving conveyor belt. Further details of the intermodal container  16  and the base unit  26  will be described in detail below. 
         [0033]      FIGS. 3 and 4  illustrate one configuration for the intermodal container  16 . The intermodal container  16  includes a storage body  42  that is formed from eleven gauge steel and supported within a support frame  44 . The support frame  44  generally includes four spaced vertical posts  46  that are joined to each other at their bottom ends by a series of lower rails  48 . A series of top rails  50  connect the top ends of the posts  46  to provide a stable frame for the storage body  42 . As illustrated in  FIGS. 3 and 4 , each corner of the support frame includes an intermodal corner connector  52 , which are standard components and are used to join the intermodal containers to each other and to the base unit  26  when the containers are mounted as shown in  FIG. 2 . 
         [0034]    Referring back to  FIGS. 3 and 4 , the frame  44  further includes a pair of forklift tubes  54  that are mounted across the front and back lower rails  48 . The tubes  54  are sized to receive tines of a forklift such that a forklift can be used to lift and move the entire intermodal container  16 . 
         [0035]    In the embodiment illustrated, the entire intermodal container  16  has a preferred length of ten feet, a preferred height of eight feet, and a preferred width of eight feet, which is a standard size for intermodal containers used to transport other types of materials. The container has an empty weight of approximately 3500 lbs. and a weight of fifteen tons when fully loaded with frac sand. 
         [0036]    As illustrated in  FIGS. 3 and 4 , the storage body  42  has a top wall  56  that extends between the series of top rails  50 . The top wall  56  includes a load door  58  connected to the top wall by a series of hinges  60 . As illustrated in  FIG. 5 , the load door  58  can pivot to an open position that provides access to a loading opening  61  to the storage body  42 . When the load door  58  is in the position shown in  FIG. 5 , frac sand can be easily loaded into the open interior  62  of the storage body  42 . It is contemplated that the load door  58  would be moved to this open position when the container  16  is initially loaded with frac sand. 
         [0037]    The load door  58  includes a central opening  64  that allows material to be transferred into the storage body  42  when the load door  58  is in the closed position. The central opening could be used when initially loading the container or when transferring frac sand from an upper container positioned above a lower container. The central opening  64  has a diameter of twenty inches, although other dimensions are contemplated. 
         [0038]    Referring back to  FIGS. 3 and 4 , in the embodiment illustrated, the central opening  64  of the load door  58  can receive either a top hatch  66  or a filler cone  68 . When the top hatch  66  is positioned above the central opening  64 , the top hatch  66  prevents material from entering into the storage body  42 . In the embodiment shown in  FIG. 4 , the top hatch  66  is mounted to the top surface of the load door  58  by a hinge and can be pivoted to a storage position. The filler cone  68  is also mounted to the top surface of the load door  58  by another hinge and can be pivoted to its usage position in which it is aligned with the central opening  64 . The filler cone  68  helps to guide material into the storage body  42 , as will be described in greater detail below. 
         [0039]    Referring now to  FIGS. 7 and 8 , the storage body  42  of the intermodal container  16  includes a lower discharge portion  70  that is defined by a pair of sloped end walls  72  and a pair of sloped sidewalls  74 . The sloped end walls  72  and sloped sidewalls  74  are each formed from steel and meet with each other at a lower end to define a discharge opening for the container  16 . The discharge opening allows frac sand to be discharged from the storage body, which is controlled by a manually operated slide gate. In the embodiment shown in  FIG. 7 , the sloped end walls  72  extend at an angle A of approximately 35° relative to horizontal while the sidewalls  74  shown in  FIG. 8  extend at an angle B of approximately 43° relative to horizontal. The angles A and B are chosen to direct the flow of material from within the storage body to the discharge opening through only the force of gravity. The specific angles selected allow the storage body to be emptied of the entire supply of frac sand is less than five minutes. 
         [0040]    Referring now to  FIG. 6 , the slide gate  76  is shown in its closed position. The slide gate  76  can be manually operated to move a control plate  78  between a fully open position and a fully closed position. The control plate  78  includes a moving mounting block  80  having a threaded receiving opening  82  coupled to an externally threaded control rod  84 . The control rod  84  extends through a front support bracket  88  and includes a drive nut  86  that can receive a tool that can be used to manually rotate the control rod  84 . As the control rod  84  rotates, the mounting block  80  moves along the length of the threaded control rod. Since the mounting block  80  is connected to the plate  78 , rotation of the control rod  84  moves the plate  78  relative to the discharge opening of the intermodal container. 
         [0041]      FIG. 3  illustrates the slide gate  76  in the closed position while  FIG. 4  illustrates the slide gate  76  in the open position. In the open position, the mounting block  80  has moved toward the support bracket  88  such that the control plate  78  is moved from beneath the discharge opening of the intermodal container  16 . In this manner, the slide gate  76  can be used to control the discharge of material from within the storage body  42 . 
         [0042]    Referring back to  FIG. 2 , after one of the intermodal containers  16  on the lower row is positioned on the base unit  26 , the top hatch  66  is removed and the filler cone  68  moved into position in which it is aligned with the top opening. Once the filler cone  68  is in position, a second intermodal container can be mounted on top of the first intermodal container as illustrated. Prior to such mounting, an intermodal pin  90  is positioned in each of the corner connectors  52 . The intermodal pin  90  is then received within a mating corner connector on a second intermodal container mounted to the lower intermodal container. 
         [0043]    Once the intermodal container of the top row is positioned on top of an intermodal container of the bottom row, the slide gate for the upper intermodal container is manually opened such that material begins to discharge from the upper container into the lower intermodal container through the top opening of the lower container. If the lower intermodal container is full, the frac sand is prevented from passing from the upper row to the lower row. However, if the lower intermodal container is empty or partially full, sand begins to flow from the upper container to the lower container. In this manner, the material from the upper row of intermodal containers can be discharged into the lower row of intermodal containers for ultimate delivery from the lower container onto the conveyor belt of the base unit  26 . 
         [0044]      FIG. 9  illustrates the base unit  26  of the present disclosure. As described previously, the base unit  26  supports a conveyor belt that transports the frac sand material from a first end  33  to the discharge end  34 . The base unit  26  includes a pair of spaced support rails  94  connected by a series of cross supports  96 . Each of the cross supports  96  includes a connector block  98  having an intermodal pin  100 . The intermodal pins  100  are received within the intermodal corner connectors contained on each of the intermodal storage containers mounted to the base unit  26 . In the embodiment illustrated, the base unit  26  includes five different mounting locations  92  that each include a discharge chute  40  that are each positioned between a pair of the cross supports  96 . The mounting locations  92  each can receive one or more stacked containers  16 , as shown in  FIG. 2 . Referring back to  FIG. 9 , the discharge chutes  40  each include a gate  102  that is selectively controlled to a user selected position between a fully closed and fully opened position. The discharge chutes  40  can thus be controlled to selectively discharge material from one of the intermodal containers when the intermodal containers are positioned above the discharge chutes, as illustrated in  FIG. 2 . 
         [0045]    As shown in  FIG. 9 , each of the support rails  94  includes a series of stabilizer legs  30  that each can be independently hydraulically adjusted to level the base unit  26  when the base unit  26  is positioned on uneven ground. 
         [0046]    Referring now to  FIG. 10 , the discharge chute  40  includes a clam shell gate  102  that is connected to an actuator  104 . In the embodiment illustrated, the actuator  104  is a hydraulic cylinder having a control rod  106  that is movable into and out of a main body  108 . When the control rod  106  is retracted within the body  108 , the clam shell gate  102  pivots in a clockwise direction to open the discharge chute  40  and allow material to pass through the chute  110  and fall onto the conveyor belt  112 . The conveyor belt  112  is supported by a series of support brackets  36  that each extend beneath the support rail  94 . Although the actuator  104  is shown as being a hydraulic cylinder, it is contemplated that the actuator  104  could be an electrical motor or similar component that is operable to move the clam shell gate  102 . 
         [0047]    When the operator wishes to supply a larger volume of sand onto the conveyor belt  112 , the actuator  104  is energized which causes the clam shell gate  102  to move in a clockwise direction and supply additional sand to the conveyor belt  112 . If the operator wishes to reduce the amount of material directed onto the conveyor belt  112 , the actuator  104  is energized in the opposite direction to extend the control rod  106  and move the clam shell gate  102  in a counterclockwise direction until it reaches the fully closed position shown in  FIG. 10 . 
         [0048]    As illustrated in  FIG. 9 , each of the discharge chutes  40  includes its own actuator  104  and clam shell gate  102 . Each of the actuators  104  can be independently operated and electronically controlled by a central controller  114 , as schematically illustrated in  FIG. 16 . The controller  114  can be mounted at any location at the well site as long as the controller is in communication with each of the actuators  104 . In one embodiment, the controller is positioned in a protective housing on the base unit and is in wired communication with the actuators  104  such that the controller  114  can issue command signals to control the movement of the chute actuator in either direction. However, it is contemplated that the controller  114  could also be located remotely from the base unit and be in wireless communication with the chute actuators  104  through conventional wireless communication techniques, such as Bluetooth. 
         [0049]    In the embodiment shown in  FIG. 16 , the actuator  104  is a hydraulic cylinder. It is contemplated that the controller  114  can selectively open and close electronically controlled hydraulic valves to control the flow of hydraulic fluid to the cylinder body of the actuator  104 . It is contemplated that the actuator  104  could take other forms, such as an electronically actuated motor or other similar component. In either case, the controller  114  sends control signals that selectively control the movement of the actuator  104  to move the clam shell gate to open and close the discharge chute leading from the intermodal container. 
         [0050]    As illustrated in  FIG. 16 , the controller is coupled to a user input device  116 , such as a keyboard, such that the user can enter control commands into the controller  114 . It is contemplated that the user input device  116  could take many different forms, such as a keyboard, a mobile device, such as a smartphone or tablet, or any other type of device that can communicate to the controller  114 . The communication between the user input device  116  and the controller  114  can be a wired connection or a wireless connection, such as but not limited to Bluetooth. It is contemplated that if the user input device  116  is a mobile device, an operator could control the operating conditions of the base unit  26  from any location within the wireless communication range of the controller  114 . 
         [0051]    In addition to controlling each of the chute actuators  104 , the controller  114  can also control the drive unit or the conveyor belt, as shown by block  118 . The controller  114  can also be connected to a display  120  that visually displays the operating parameters for the entire base unit. The display  120  could be located at or near the base unit or could be part of the user input device  116 . 
         [0052]    Referring now to  FIG. 11 , each of the support brackets  36  supports a series of rollers  122  that allow the lower run of the conveyor belt  112  to be supported and move along the length of the base unit. The conveyor belt  112  has a width of twenty-four inches in the illustrated embodiment. Each of the rollers  122  is mounted to a lower support plate  124 , which in turn is connected to the side brackets  126 . A series of braces  128  provide additional strength and stability to support the conveyor belt  112  when the conveyor belt  112  is loaded with material. 
         [0053]      FIG. 12  illustrates the use of a rail car  130  to support five separate intermodal containers  16  for initial loading from a pit conveyor  132 . The pit conveyor  132  can be located at a sand pit or other location where sand is mined and loaded for distribution. 
         [0054]      FIG. 13  illustrates the same intermodal containers  16  mounted on one or more trailers  134  pulled by a cab  136 . As in the embodiment shown in  FIG. 12 , each of the containers  16  can be loaded with sand from a pit conveyor  132  while supported on toe trailer  134 . 
         [0055]      FIG. 14  illustrates the use of a crane  135  that is located at the well site and used to stack the containers  16 . Once the containers are empty, the crane and/or the forklift  20  can be used to load the empty containers back on the trailer or rail car. The empty containers can then be returned to the mine or loading facility on the trailers  134  pulled by the cab  136  shown in  FIG. 15 . 
         [0056]    As most clearly understood in  FIG. 1 , the transportation, stacking and unloading of the individual intermodal containers  16  allows a well site operator to store a large volume of sand at a well site. Once each of the individual containers  16  has been emptied, the container can be loaded onto a trailer and hauled back to the mine for reloading with frac sand. Since the intermodal containers  16  can be loaded onto conventional trailers and rail cars, the intermodal containers provide the frac proppant provider with the flexibility of utilizing the same containers for shipping, storage and distribution of the sand at the well site. The intermodal containers are designed to be stacked in the manner illustrated in  FIG. 1 , and can be moved around the well site utilizing various different types of equipment, such as forklifts and cranes. 
         [0057]    This written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to make and use the invention. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims.