Abstract:
A press comprising a body, the body containing a chamber interposed between a ram and an end wall, the ram connected to a piston to compact material against the end wall to generate a pressed object, the chamber comprising an opening for loading the material into the chamber, and a series of perforations to enable liquid contained in the material to be expelled from the chamber during advancement of the piston towards the end wall.

Description:
[0001]    This application claims priority to U.S. Provisional Patent Application No. 62/105,568 filed on Jan. 20, 2015, the contents of which are incorporated herein by reference. 
     
    
     TECHNICAL FIELD 
       [0002]    The following relates to a method and apparatus for pressing drill cuttings to remove drilling mud and prepare the drill cuttings for disposal. 
       DESCRIPTION OF THE RELATED ART 
       [0003]    Drilling processes used in various industries such as oil and gas and mining use drilling fluids to lubricate and cool the drill bit, and to carry drilled cuttings out of the bore hole. Drilling fluids can also be used to drive downhole mud motors. Drilling fluids, also known as “mud” can be expensive. Solids control systems are often incorporated into the drilling process to remove solids in an effort to reuse at least some recovered mud in subsequent drilling operations. 
         [0004]    For example, shale shakers are well known machines that are often used as the primary solids separation equipment on a drilling site. A mixture of drilling fluid and drill cuttings that is brought to the surface during the drilling operation flows into one or more shale shakers to be processed. Once processed, recovered mud is fed to a mud tank for further processing to remove finer solids before being reused by the drilling equipment. The solids removed by the shale shaker are discharged for further treatment or disposal. The shale shaker separates the mud from the cuttings using a shaker basket having a screen that allows mud to collect in the mud tank as the mud and cuttings are fed over the screen while the shaker basket is vibrated. 
         [0005]    The drill cuttings that are discharged from the shale shaker typically need to be treated to meet environmental or other regulations, as well as to make them suitable for transporting away from the drilling site. For example, drill cuttings can be mixed with wood shavings to create a dry enough product to be hauled away for disposal. 
       SUMMARY 
       [0006]    In one aspect, there is provided a press comprising a body, the body containing a chamber interposed between a ram and an end wall, the ram connected to a piston to compact material against the end wall to generate a pressed object, the chamber comprising an opening for loading the material into the chamber, and a series of perforations to enable liquid contained in the material to be expelled from the chamber during advancement of the piston towards the end wall. 
         [0007]    In another aspect, there is provided a system for recovering drilling fluid from drill cuttings, the system comprising: a first collection tank for collecting drill cuttings output from a shale shaker; a conveyance system for conveying the drill cuttings to a press; the press comprising a body, the body containing a chamber interposed between a ram and an end wall, the ram connected to a piston to compact the drill cuttings against the end wall to generate a pressed object, the chamber comprising an opening for loading the drill cuttings into the chamber, and a series of perforations to enable drilling fluid contained in the drill cuttings to be expelled from the chamber during advancement of the piston towards the end wall; and a second collection tank for collecting the pressed objects. 
         [0008]    In yet another aspect, there is provided a method of recovering drilling fluid from drill cuttings, the method comprising: collecting drill cuttings in a chamber, the chamber being interposed between a ram operated by a piston and an end wall of a press; advancing the piston towards the end wall to compact the drill cuttings; reversing the piston after the drill cuttings are compacted to generate a pressed cutting; opening an end cap comprising the end wall; and advancing the piston towards the pressed cutting to expel the pressed cutting from the chamber. The method can also include reversing the piston and closing the end cap. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0009]    Embodiments will now be described by way of example only with reference to the appended drawings wherein: 
           [0010]      FIG. 1  is a schematic diagram of a drilling fluid recovery system; 
           [0011]      FIG. 2  is a schematic elevation view of a drill cuttings press integrated with a shale shaker; 
           [0012]      FIG. 3  is a flow chart illustrating a process for operating the drill cuttings press shown in  FIG. 2 ; 
           [0013]      FIGS. 4( a ) to 4( f )  are sectional schematic views illustrating operation of a drill cuttings press; and 
           [0014]      FIG. 5  is a plan view of a drill cuttings press having multiple processing chambers. 
       
    
    
     DETAILED DESCRIPTION 
       [0015]    Additional mud can be extracted from drill cuttings and the drill cuttings can be processed into a transportable form, without mixing in additional materials, by pressing “wet” drill cuttings processed by a shale shaker in a press having perforations at a compaction end. In this way, the press squeezes excess drilling mud from the wet cuttings to further improve mud recovery while removing moisture from the cuttings. At the same time, the cuttings are compacted into a block to facilitate disposal. It has been found that the resulting block is dry enough for immediate transport, i.e., without needing to be mixed with additional materials such as wood shavings. The additional mud that is squeezed from the press can also be fed back into the mud system for further processing if necessary before being reused in the drilling system. 
         [0016]    Turning now to  FIG. 1 , a drilling fluid recovery system  10  is shown, which can be operated with a mud system  12  used in a drilling process. The mud system  12  operates to provide lubrication, cooling, and even propulsion for down hole drilling equipment such as a drill bit, mud motor, etc. As the drilling fluid or “mud” circulates through the drilling system, drill cuttings produced by the drilling process are carried back up to surface. The mud system  12  therefore generates a mixture of mud and drill cuttings  14  that need to be treated and/or disposed of. 
         [0017]    As discussed above, it is typical to use a shale shaker  16  as a primary solid recovery tool in a drilling process. The mixture of mud and cuttings  14  flows into the shale shaker  16  to separate recoverable mud  18  from generally “wet” cuttings  20  (i.e. cuttings that are at least in part containing some drilling fluid). The recoverable mud  18  may require further processing to remove finer particulate, and can be fed into a mud system return  26  in order to be reused. 
         [0018]    It has been recognized that rather than mixing the wet cuttings  20  with materials such as wood shaving to enable transport, the wet cuttings  20  can be further processed to remove the remaining mud  18  by pressing the wet cuttings  20  in a cuttings press  22 . The cuttings press  22  squeezes the wet cuttings  20  to further extract recoverable mud  18  and therefore increase the amount of mud  18  that is reused by the mud system  12 . Furthermore, the pressed cuttings  24  are found to be dry enough for transport, which can save an additional processing step to dry out the material. For example, the pressed cuttings  24  can be deposited directly into a container for removal, transport, etc. 
         [0019]      FIG. 2  illustrates an example of a configuration for the cuttings press  22  when integrated with a shale shaker  16 . Mud and cuttings  14  are fed into a hopper  32  via a flow line  30 . The hopper  32  feeds the mud and cuttings  14  onto a screen bed  34 , which is operated by a vibrator (not shown) to separate mud  18  from drill cuttings  20  as is known in the art. In this example configuration, the separated mud  18  flows through a mud return  36  to a main mud system return line  26 . 
         [0020]    The wet cuttings  20  that exit the shale shaker  16  typically proceed down a shale slide  38 , and are collected in a cuttings collection tank  40 . A conveyance system  42  such as a series of augers is used to convey the wet cuttings  20  from the collection tank  40  up and towards an opening  44  in the press&#39;s body, which allows the wet cuttings  20  to collect within a chamber  46 . A cylinder  48  houses a piston  90  and operates a ram  92  (see  FIG. 4 ) to press the collected cuttings  20  within the chamber  46  and towards an end cap  50 . Near the end cap  50 , the chamber  48  includes a series of holes or perforations to provide a screen for mud  18  to be squeezed from the wet cuttings  20  and exit the chamber  48 . For example, 1/16 inch holes have been found to be suitable. The squeezed mud  18  is collected in a fluid collection tank  54 . The squeezed mud  18  can then be fed into the mud system return  26 , e.g., for further processing using a centrifuge (not shown) or other equipment used to remove finer particulate matter so that the squeezed mud  18  can be reused. The pressed cuttings  24  are then discharged, as discussed in greater detail below, into a cuttings disposal tank  56 . It has been found that a piston  90  that can deliver 62 tonnes of pressure, and a 14 ½″ inside diameter for the chamber  48  are suitable for extracting the additional mud  18  in the configuration shown herein, although other operating pressures and chamber sizes are possible within the principles discussed herein. 
         [0021]      FIG. 3  illustrates operations that can be performed in order to press wet cuttings  20  and generate pressed cuttings  24  and additional mud  18  using the configuration shown in  FIG. 2 . At  60 , wet cuttings  20  are collected from the shale shaker  16  in the cuttings collection tank  40 . Once cuttings  20  have accumulated in the cuttings collection tank  40 , the auger or other conveyance system  42  is started at  62  to begin conveying the cuttings  20  into the cuttings press chamber  46  at  64  (with the piston  90  and ram  92  retracted). After the chamber  46  has been loaded with at least enough cuttings  20  to form a pressed cutting  24 , the auger is stopped at  66 . The chamber  46  therefore includes a pile of wet cuttings  20  therewithin as shown in  FIG. 4( a ) . As also shown in  FIG. 4( a ) , the cylinder  48  houses a piston  90 , which drives a ram  92  to compress the wet cuttings  20  within the chamber  46 . The piston  90  is driven at  68  to press the cuttings as shown in  FIG. 4( b ) . This operation continues until it is determined at  70  that the pressing operation is done. As the piston  90  presses the wet cuttings  20  to form a pressed cutting  24 , excess mud is squeezed out of the press  26  through the perforations  52  to be collected in the fluid collection tank  54 . When the compaction operation is complete (i.e. after at least some fluid has been expelled from the press  26 ), as shown in  FIG. 4( c ) , the piston  90  can be reversed at  72 , which is also illustrated in  FIG. 4( d )  to release pressure on the end cap  50 . The end cap  50  is then opened at  74 , as shown in  FIG. 4( e ) , which enables the piston  90  to be advanced at  76  to discharge the pressed cutting  24  as shown in  FIG. 4( f ) . The piston  90  is then reversed again at  78  to a start position (e.g., fully retracted), and the end cap  50  is closed at  80  to allow for the process to be repeated by starting the auger again at  62  to convey more wet cuttings  20  into the press chamber  48 . 
         [0022]    While a particular configuration is shown in  FIGS. 2 and 4 , and exemplary operations are shown in  FIG. 3 , various modifications are possible. For example, while shale shakers  16  are typical solid removal tools using in drilling processes, the press  22  described herein can be used with any suitable machine that generates wet cuttings  20  that are capable of being pressed. For example, the press  22  could be used instead of a shale shaker  16 . Similarly, while a conveyance system  42  such as an auger is herein illustrated, manual methods for loading the wet cuttings  20  into the cuttings press  22  are equally possible. Moreover, the end cap  50  and its operation illustrated in  FIG. 4  is only one way to remove the pressed cuttings from the press  22 . For example, the pressed cuttings  24  can be manually removed without relying on operation of the piston  90 . The end cap  50  can also be hinged at the bottom of the cuttings press  22 , or a top or bottom release hatch (or other access mechanism) could be used, without departing from the principles described herein. The perforations  52  shown in  FIGS. 2 and 4  are also illustrative only and may be implemented in other patterns and consume varying amounts of the outer surface of the cuttings press  22 . 
         [0023]      FIG. 5  illustrates a multi-chamber cuttings press  22 ′. In the example shown in  FIG. 5 , the conveyance system  42  feeds wet cuttings  20  into a first opening  44   a  and a second opening  44   b  to load a first chamber  46   a  and a second chamber  46   b.  First and second pistons  90  and rams  92  can be operated in tandem or independently to generate a pair of pressed cuttings  24  that can be discharged from a single end cap  50 . It can be appreciated that a single end cap  50  as shown in  FIG. 5  is only one option, i.e. multiple end caps  50  can also be employed. Moreover, more than two chambers  46  can also be used within the same system  10 . 
         [0024]    Although not shown in the figures, a control system can also be incorporated into the system  10  to automate the loading and pressing of the wet cuttings  20 . Such a control system can be manually controlled or pre-programmed to cycle through stages of loading material, pressing material, and expelling pressed material, e.g., by turning augers on or off, and opening the end cap  50  using a servo-motor or other electromechanical device. For example, such a control system can be programmed to control the system  10  substantially as shown in  FIG. 3 . That is, at least some of the operations shown in  FIG. 3  can be adapted for automated control using computer executable instructions. 
         [0025]    It will be appreciated that for simplicity and clarity of illustration, where considered appropriate, reference numerals may be repeated among the figures to indicate corresponding or analogous elements. In addition, numerous specific details are set forth in order to provide a thorough understanding of the examples described herein. However, it will be understood by those of ordinary skill in the art that the examples described herein may be practiced without these specific details. In other instances, well-known methods, procedures and components have not been described in detail so as not to obscure the examples described herein. Also, the description is not to be considered as limiting the scope of the examples described herein. 
         [0026]    The examples and corresponding diagrams used herein are for illustrative purposes only. Different configurations and terminology can be used without departing from the principles expressed herein. For instance, components and modules can be added, deleted, modified, or arranged with differing connections without departing from these principles. 
         [0027]    The steps or operations in the flow charts and diagrams described herein are just for example. There may be many variations to these steps or operations without departing from the principles discussed above. For instance, the steps may be performed in a differing order, or steps may be added, deleted, or modified. 
         [0028]    Although the above principles have been described with reference to certain specific examples, various modifications thereof will be apparent to those skilled in the art as outlined in the appended claims.