Abstract:
Embodiments disclosed herein provide an apparatus that includes a container configured to store and transport drilling waste, a lid coupled to the container, and at least one arm coupled to the lid and configured to lift or lower the lid when moved, wherein the at least one arm comprises a counterweight. Disclosed embodiments also provide a method of opening and closing an apparatus. The method includes moving at least one arm coupled to a lid of the apparatus to an open position, wherein the apparatus is configured to store and transport drilling waste, disposing drilling waste in the apparatus, and moving the at least on arm coupled to the lid of the apparatus to a closed position. Disclosed embodiments also provide a method of modifying a mud skip that includes coupling at least one arm to a lid of the mud skip configured to store and transport drilling waste, wherein the at least one arm comprises a counterweight.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]     This application, pursuant to 35 U.S.C. § 119(e), claims priority to U.S. Provisional Application Ser. No. 60/778,787, filed Mar. 3, 2006. That application is incorporated by reference in its entirety. 
     
    
     BACKGROUND OF INVENTION  
       [0002]     1. Field of the Invention  
         [0003]     Embodiments disclosed herein relate generally to containers for storing and transporting drilling waste. More specifically, the present invention relates to skips for storing and transporting drill cuttings and substances produced in the course of offshore drilling operations.  
         [0004]     2. Background Art  
         [0005]      FIG. 1  shows a typical offshore drilling rig  100  having a derrick  102 , a floating platform  104 , and a riser  106  that extends from the offshore drilling rig  100  down to the seabed  110 . In drilling operations, particularly in the drilling of oil and gas wells large amounts of waste material is generated when drilling a wellbore  108  in an earth formation. The waste material generated is also known as drill cuttings. Drill cuttings may comprise, for example, rock, dirt, shale, and other debris. Drilling fluid (“drilling mud”) is often pumped downhole for a number of different purposes, such as lubrication of the drill string within the riser  106 , prevention of corrosion, and transport of drill cuttings to the surface. Drilling fluid may be oil or water-based, although oil-based drilling fluids are preferred in lower sections of bore, and are also generally less costly than water-based drilling fluids.  
         [0006]     Once the drilling fluid is returned to the surface, it is passed through screens, vibratory separators, or other filtering arrangements to separate the waste material and drill cuttings from the drilling fluid. The drilling fluid may then be sent to a reservoir or returned to the system and reused. Drilling cuttings processed by filtering arrangements may contain approximately 10% to 20% moisture (oil, water) by weight. Because the waste material and drill cuttings contain contaminants, such as chemicals, hydrocarbons such as oil and other components hazardous to the environment, environmental regulations require that the waste material and drill cuttings be processed and disposed of in an environmentally acceptable manner. Contaminated waste material and drill cuttings recovered from an offshore drilling rig typically require removal from the rig or wellbore for treatment on land to decontaminate them before they can be safely disposed.  
         [0007]     The waste material and drill cuttings are collected and stored on the drilling platform  114  or vessel in small containers, also known as mud skips, skips, or cuttings boxes, before being transported onshore for processing. The skips may be lifted by a crane  112  and loaded on a ship  116 , or supply boat, for transportation to a shore base facility. The skips typically have about a five ton capacity and a typical drilling operation may produce up to 800 ton of drilling waste. Many skips are necessary on a typical drilling rig to handle the large amounts of drill cuttings generated. Dedicated crews are necessary to handle the skips on the drilling and at the shore base facility, cleaning crews are necessary to clean the skips after each use, and crews are needed to address safety and environmental concerns in each operation handling the skips.  
         [0008]      FIGS. 2 and 3  show examples of typical mud skips  220  having a lid  222  coupled to the top  224  of the tank  220 . A plurality of lifting eyes  228  are coupled to the tank  220 . The lifting eyes  228  are configured to receive a hook (not shown) for lifting the tank  220  with a crane  112  ( FIG. 1 ). Additionally, the tank  220  has slots  230  that allow the tank  220  to be lifted or transported by, for example, a forklift. The lid  222  is coupled to the top  224  of the tank  220  by one or more hinges  226  (also shown in  FIG. 4 ). As shown in  FIGS. 3 and 5 , the lid  222  is manually opened by standing on the top  224  of the skip  220  and lifting on the on the side  230  opposite the hinged  226  side.  
         [0009]     As shown in  FIG. 6 , after the lid  222  on the skip  220  is manually opened, waste material and drill cuttings separated from the drilling fluid are discharged from a separator  232  into the skip  220 . The separator  232  may be disposed in a structure  234  that allows the separator to be positioned above the skip  220 . Once the skip  220  is full, as viewed through, for example, a portal  236  disposed on the top  224  of the skip  220 , the lid  222  may be closed and moved to a storage location on the drilling platform  114  ( FIG. 1 ) or to a ship  116  ( FIG. 1 ) for transportation onshore. Corresponding locks  238  on the lid  222  and the top  224  of the skip  220  secure the lid in the locked position to prevent leaks or spills of the drill cuttings during transportation.  
         [0010]     Typically, mud skips for offshore drilling rigs range in size from 15 barrel (bbl) containers to 25 bbl containers. The skips may be comprised of galvanized steel that is internally coated for corrosion resistance. A skip, when empty, may range in weight from approximately 3000 lbs (1300 kg) to 4500 lbs (2000 kg) or more. The size of a skip may also vary based on the space available on a drilling platform for storage and the amount of drill cuttings produced. For example, a skip may vary in size from approximately 7.5 ft long by 4.5 ft wide by 4 ft high to 8 ft long by 8 ft wide by 4 ft high or larger. Accordingly, the gross total weight and capacity of each skip varies due to the variation in empty weight and size of the skip. The lids of the skips are also extremely heavy so as to provide a greater seal of the skip opening. Typically, a lid may weigh several hundred pounds or more. The heavy weight of the lids and the position of the operator atop the skip often present a safety concern for personnel when opening and closing the lids. Further, the lids are typically only safely secured in a fully open or fully closed position.  
         [0011]     Accordingly, there exists a need to effectively and safely seal and store drill cuttings and waste material in mud skips.  
       SUMMARY OF INVENTION  
       [0012]     In one aspect, embodiments disclosed herein relate to an apparatus comprising a container configured to store and transport drilling waste, a lid coupled to the container, and at least one arm coupled to the lid and configured to lift or lower the lid when moved, wherein the at least one arm comprises a counterweight.  
         [0013]     In another aspect, embodiment disclosed herein relate to a method of opening and closing an apparatus, the method comprising moving at least one arm coupled to a lid of the apparatus to an open position, wherein the apparatus is configured to store and transport drilling waste, disposing drilling waste in the apparatus, and moving the at least one arm coupled to the lid of the apparatus to a closed position.  
         [0014]     In another aspect, embodiments disclosed here relate to a method of modifying a mud skip, the method comprising coupling at least one arm to a lid of the mud skip configured to store and transport drilling waste, wherein the at least one arm comprises a counterweight.  
         [0015]     Other aspects and advantages of the invention will be apparent from the following description and the appended claims. 
     
    
     BRIEF DESCRIPTION OF DRAWINGS  
       [0016]      FIG. 1  shows a conventional offshore drilling rig.  
         [0017]      FIG. 2  shows a conventional mud skip.  
         [0018]      FIG. 3  shows another conventional mud skip.  
         [0019]      FIG. 4  shows a hinge of lid of a mud skip.  
         [0020]      FIG. 5  shows a hinged lid of a mud skip.  
         [0021]      FIG. 6  shows a conventional mud skip being filled.  
         [0022]      FIG. 7  shows a side view of a mud skip in accordance with an embodiment of the invention.  
         [0023]      FIG. 8  shows a front view of a mud skip in accordance with an embodiment of the invention.  
         [0024]      FIG. 9  shows a top view of a mud skip in accordance with an embodiment of the invention.  
         [0025]      FIG. 10  shows a side view of a mud skip in accordance with an embodiment of the invention.  
     
    
     DETAILED DESCRIPTION  
       [0026]     In one aspect, embodiments disclosed herein relate to a storage container for drilling waste. In particular, disclosed embodiments provide an arm coupled to a lid of a mud skip for moving and securing the lid. Additionally, disclosed embodiments provide a method for modifying a mud skip to include an arm for moving and securing the lid of a mud skip. In one embodiment, an arm coupled to the lid of the mud skip allows the operator to open and close the lid while standing beside the mud skip. In one embodiment, the arm comprises a counterweight that reduces the amount of force or weight necessary to move the heavy lids open or closed. In another embodiment, the arm, in conjunction with an arm lock, secures the lid in open or closed positions by varying increments. Accordingly, embodiments of the present invention provide a safer and more effective mud skip.  
         [0027]      FIGS. 7-9  show an embodiment of a mud skip  730 . The mud skip  730  comprises a container  728  and a frame  729  that provides support and mobility to the mud skip  730 . A lid  732  is coupled to the top  734  of the mud skip  730 . The container  728  and the lid  732  may be formed from any material known in the art for forming containers for storing drilling waste. For example, in one embodiment, the container  728  and the lid  732  may be formed of galvanized steel. Further, the container  728  may be internally coated with a corrosion resistant material. The lid  732  may be coupled by any means known in the art.  
         [0028]     For example, at least one hinge  944  ( FIG. 9 ) may couple the lid  732  to the top  734  of the mud skip  730 . At least one arm  736 , or lid key, is coupled to the lid  732  on the hinged side  738  of the lid  732 . A second arm  736   a  may be coupled to the lid  732  of the mud skip  730  on the side opposite the arm  736  and oriented in a similar manner as arm  736 .  
         [0029]     The arm  736  may be coupled to the lid  732  by any method known in the art for safely securing two load bearing pieces together. For example, in one embodiment the at least one arm  736  may be bolted to the lid  732 . Alternatively, the at least one arm  736  may be welded to the lid  732 . In yet another embodiment, the at least one arm  736  may be releasably coupled to the lid  732 . In this embodiment, the at least one arm  736  may be coupled to the lid  732  to lift or lower the lid  732  and then released and removed from the lid  732  when not in use. In this example, the at least one arm  736  used to lift and lower the lid  732  of a first mud skip may be removed and used to lift and lower a lid of a second mud skip. Additionally, the releasable coupling of the at least one arm  736  with the lid  732  allows the operator to remove the at least one arm  736  from lid  732  of the mud skip  730  to prevent interference of or damage to the arm  736  when mud skips are transported or stacked on top of one another.  
         [0030]     The at least one arm  736  may comprise at least two sections  750 ,  752  (shown in  FIG. 8 ) that may be integrally or separately formed, so long as the first section  750  and the second section  752  form a rigid junction. In the embodiment shown in  FIGS. 7, 8 , and  9 , the first section  750  of the at least one arm  736  extends out laterally from the mud skip  730  along the axis of the hinged side  738  of the lid  732  and past the outer side edge  942  of the container  728 . The second section  752  of the at least one arm  736  extends downwardly towards the base  740  of the mud skip  730 . One of ordinary skill in the art will appreciate that the at least one arm  736  may be formed so that a first section extends across the width of the lid  732  past both sides of the container and two side sections may be disposed on either side of the container and formed in the same manner as the second section  752  of the at least one arm  736 . The second section  752  may extend downwardly at an angle “A” defined between the axis of the second section  752  of the at least one arm  736  and an axis formed perpendicular to the axis of the first section  750  of the at least one arm  736 . In one embodiment, angle A may be between 0 and 90 degrees. For example, when the lid  732  is in the closed position, the second section  752  of the at least one arm  736  may extend downwardly at an angle A of approximately 50 degrees.  
         [0031]     In one embodiment, the second section  752  of the at least one arm  736  may comprise a counterweight that accounts for the weight of the lid  732 . In this embodiment, the weight of the counterweight is such that when the second section  752  of the at least one arm  736  is moved forward, as indicated at F, the lid  732  may be lifted open, indicated at O. Accordingly, the second section  752  may be moved backward, indicated at B, to close the lid  732 . In one embodiment, the counterweight may be integrally formed with the second section  752 . For example, the second section  752  of the at least one arm  736  may be formed of a dense material in a selected size and shape, thereby providing sufficient weight to reduce the force or weight required to open the lid  732 . The arm  736  may be formed of any material known in that art such that the arm may withstand the weight and movement of the lid  732 . Alternatively, additional masses or weights may be coupled to the second section  752  of the at least one arm to provide sufficient weight to reduce the force or weight required to open the lid  732 .  
         [0032]     In an alternative embodiment, a second section  1052  of the at least one arm  736  may extend upwardly away from the base  740  of the mud skip  730 , as shown in  FIG. 10 . In this embodiment, the second section  1052  of the at least one arm  736  may be moved backward, indicated at B, thereby moving the lid  732  open, indicated at O. To close the lid  732 , the second section  1052  may be moved forward, indicated at F. In this embodiment, at least one groove or notch (not shown) may be formed on the bottom  1066  of the container  728  to accommodate the upwardly extending second section  1052  of the at least one arm  736  when multiple skips are stacked on top of one another. The second section  1052  disposed in the groove of a skip stacked on top of the mud skip  1030  may also prevent the stacked skip from moving or sliding off of the base skip  1030 . Alternatively, the at least one arm  736  may be releasably coupled to the lid  732  and removed when stacking or transporting mud skips.  
         [0033]     In this alternative embodiment, the second section  1052  of the at least one arm  736  may comprise a counterweight that accounts for the weight of the lid  732 . In this embodiment, the weight of the counterweight is such that when the second section  1052  of the at least one arm  736  is moved backward, as indicated at B, the lid  732  may be lifted open, indicated at O. Accordingly, the second section  1052  may be moved forward, indicated at F, to close the lid  732 . In one embodiment, the counterweight may be integrally formed with the second section  1052 . For example, the second section  1052  of the at least one arm  736  may be formed of a dense material in a selected size and shape, thereby providing sufficient weight to reduce the force or weight required to open the lid  732 . The arm  736  may be formed of any material known in that art such that the arm may withstand the weight and movement of the lid  732 . Alternatively, additional masses or weights may be coupled to the second section  1052  of the at least one arm to provide sufficient weight to reduce the force or weight required to open the lid  732 .  
         [0034]      FIGS. 7-9  show an embodiment of the mud skip  730  further comprising an arm lock  754 . In this embodiment, at least one arm  736  may be engaged with the arm lock  754  at pre-selected locations, thereby securing the lid  732  open or closed at corresponding varying increments. In one embodiment, the arm lock  754  may comprise a plate  758  coupled to the outer side wall  760  of the container  728 . In this embodiment, several locking holes  756 , for example, threaded holes, may be formed in the plate  758  so as to provide pre-selected locking locations. As at least one arm  736  is moved forward F, the operator may lock the at least one arm  736  into a selected location  756  by securing a locking device (not shown), for example, a bolt, screw, or other similar structure, through the arm  736  and into the location  756 , thereby securing the lid  732  open or closed at a corresponding increment. In this embodiment, the plate  758  may be curved so as to maintain alignment with the locking device coupled to the arm  736 . One of ordinary skill will appreciate that other arm locks coupled to the at least one arm  736  for securing the at least one arm  736  at pre-selected locations, thereby securing the lid  732  open or closed at varying increments may be used without departing from the scope of the invention.  
         [0035]     Similarly,  FIG. 10  shows an embodiment of the mud skip  1030  further comprising an arm lock  1054 . In this embodiment, at least one arm  736  may be engaged with the arm lock  1054  at pre-selected locations, thereby securing the lid  732  open or closed at corresponding varying increments. In one embodiment, the arm lock  1054  may comprise a plate  1058  coupled to the top  734  of the container  728 . In this embodiment, several locking holes  1056 , for example, threaded holes, may be formed in the plate  1058  so as to provide pre-selected locking locations. As at least one arm  736  is moved backward B, the operator may lock the at least one arm  736  into a selected location  1056  by securing a locking device (not shown), for example, a bolt, screw, or other similar structure, through the arm  736  and into the location  1056 , thereby securing the lid  732  open or closed at a corresponding increment. In this embodiment, the plate  1058  may be curved so as to maintain alignment with the locking device coupled to the arm  736 . One of ordinary skill will appreciate that other arm locks coupled to the at least one arm  736  for securing the at least one arm  736  at pre-selected locations, thereby securing the lid  732  open or closed at varying increments may be used without departing from the scope of the invention.  
         [0036]     Typically, an operator must stand on top of the mud skip  730  to lift the lid  732 . To lift the lid it may take 140 lbs (65 kg) of weight or more, as may be determined by a mechanical suspended scale. In contrast, embodiments disclosed herein, for example, shown in  FIGS. 7-9 , allow the operator to stand next to the mud skip  730  and push at least one arm  736  forward to lift the lid  732  open with less force or weight than required to lift the lid separately. For example, wherein the weight of the lid  732  would typically require 140 lbs (65 kg) to lift in the conventional manner, in the embodiment shown in  FIG. 7 , the weight required to move the arm  736  forward, and thereby open the lid  732 , is approximately 10 lbs (5 kg). In another embodiment, two operators may be positioned on opposite sides of the mud skip  730  and each push an arm  736 ,  736   a  forward, thereby lifting the lid  732  open and reducing the force or weight necessary to lift the lid  732 .  
         [0037]     Embodiments of the present invention may advantageously provide a mud skip with an arm for lifting a lid of the mud skip. Embodiments of the present invention may reduce the risk of injury to personnel while operating mud skips. Further, embodiments of the invention allow for a more securely positioned lid, in both the open and closed positions. Embodiments of the present invention may prevent movement of skips when multiple skips are stacked.  
         [0038]     While the invention has been described with respect to a limited number of embodiments, those skilled in the art, having benefit of this disclosure, will appreciate that other embodiments can be devised which do not depart from the scope of the invention as disclosed herein. Accordingly, the scope of the invention should be limited only by the attached claims.