Patent Abstract:
Several well bore clean-out apparatus&#39; are disclosed that provides a method of cleaning a well bore while the apparatus&#39; are being deployed into a well forcing well bore fluid into a work string and for moving solids to the surface. A method of cleaning multiple diameters of well casings is also disclosed. A method of circulating or reverse circulating the well at anytime during the deployment of the apparatus&#39; is disclosed.

Full Description:
PRIORITY INFORMATION  
       [0001]    This application claims the benefit of U.S. Provisional Application No. 60/432,418 on Dec. 12, 2002. 
     
    
     
       FIELD OF THE INVENTION  
         [0002]    The field of this invention relates to a method of cleaning a well bore with a tubular wiper and valve arrangement.  
         BACKGROUND OF THE INVENTION  
         [0003]    During the process of drilling and completing a well it is often desirable to remove all solid materials from the mud system in the well bore as well as removal of cement, metal and other materials which may cling to the wall of the tubular or in the case of a deviated well be laying on the side or bottom of the partially horizontal tubular. In many cases it is also desirable to change out the mud system in the well bore to a completion fluid, which is free of solids.  
           [0004]    Currently this process is accomplished by running a tubular (commonly called a “work string”) to or near the bottom of the well. Then circulating fluid through or down this work string and into the annulus between the tubular and well bore. Circulation is accomplished by pumping fluid down the work string and back to the surface through the annulus between the work string and casing.  
           [0005]    To assist in these process mechanical devices such as casing scrapers and brushes are attached near the bottom of the work string to remove the solids that may cling to the casing such as cement, formation debris or metal particles.  
           [0006]    Circulation to remove the solids requires turbulent flow. In most if not all cases sufficient pump capacity is not available to accomplish the required flow rates. The flow area of the annulus is no less than 3 times and more often 5 to 10 times that of the work string. Therefore the flow rate required to maintain turbulent flow in the annulus is at least 3 times that required in the work string. By causing the solid laden fluid to flow to the surface through the work string the solids are more likely to be removed from the well due to the higher velocity fluid stream in the work string. This is particularly true in deviated wells where it is known that the mud system will “channel” and not cover the entire annular area. In these cases the solids remain in the well bore and can cause failure of packers, valves, etc. that are run in the well as a part of the completion process. These solids can also cause formation damage that prevents the well from producing at its maximum or prevents injection into the formation.  
           [0007]    It is therefore evident to those familiar with these processes that it is desirable to move the solids to the surface by forcing them into the highest velocity flow available this being the work string.  
           [0008]    The newest known device that represent this type of well bore clean out method is from Baker Oil Tools titled “The Well Bore Custodian” These devices are run and pulled from the well bore to remove the solids from the casing wall and place them in the mud system. Most devices require circulation to remove the solids; recognizing that circulation alone can not remove the solids, Bakers&#39; device attempts to remove the solids by filtering them from the mud system. This device relies on the filtering system to retain the solids until the device is removed from the well. As seen in the prior art, filtering devices have been tried in the past and found not to remove all of the solids.  
           [0009]    In the past, as illustrated in several patents, there have been a variety of tools and techniques used to remove debris. U.S. Pat. No. 2,782,860 shows the use of reverse circulation into a pickup tube held by a packer inside a tubular. Several devices involve pulling vacuum on the tubular to suck fluid and debris into it. Some examples are U.S. Pat. Nos. 3,775,805; 4,630,691; 5,269,384; 5,318,128; 3,958,651 and 5,033,545 (fluid jet creates a vacuum). U.S. Pat. No. 5,402,850 uses a seal and crossover to force fluid with debris into the annulus around the tubular string for the trip to the surface. Other techniques involve reverse flow into the tubing string, such as: U.S. Pat. No. 4,944,348 and U.S. Pat. No. 5,069,286. Also of interest are U.S. Pat. Nos. 5,562,159 and 5,718,289.  
         SUMMARY OF THE INVENTION  
         [0010]    Multiple embodiments of well bore clean out systems are disclosed. These embodiments remove the solids from the well bore annulus as soon as they are encountered and places them into the tubular being run in the well bore. This will place the solids into the inside of the work string where higher velocities will move the solids to the surface where they can be separated from the mud system. This is made practical by newly patented devices such as those disclosed in patents U.S. Pat. No. 6,390,190 and U.S. Pat. No. 6,415,862.  
           [0011]    The system consists of at least one circulator assembly having a port below a packer cup to divert fluid from the annulus into the work string as the work string is being lowered into the well bore. This system can consist of a circulator assembly for each casing size in the well being cleaned, in other words, multiple circulator devices on one work string with porting to control the flow of fluids.  
           [0012]    Valve assemblies are also be disclosed which selectively open and/or close to direct flow either into the tubular or around the packer cup. This valve assembly provides a path for fluid around the packer cup when the work string and circulator is removed from the well.  
           [0013]    A method comprises of directing the mud above any mechanical cleaning devices and through a port below the packer cup into the tubular immediately below the packer cup.  
           [0014]    A valve assembly is disclosed that selectively opens the very bottom of the work string to allow reverse circulation to the bottom of the work string to thoroughly clean the well bore prior to removing any one of the assemblies from the well bore.  
           [0015]    An arrangement of packer cups is disclosed that assures that annulus fluid between circulators in different casing strings will be directed into the work string. In addition, a process comprises removing solids from the fluid system and casing wall. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0016]    [0016]FIG. 1 is a sectional view of a well showing the apparatus positioned in a well having a single casing.  
         [0017]    [0017]FIG. 2 is a sectional view of a well having a casing and liner of different sizes showing different sizes of the apparatus positioned in each of the casing string and liner.  
         [0018]    [0018]FIGS. 3 and 3A are a sectional view of a mechanically operated apparatus being run into a well showing the port opened and a cup seal to force the fluid in the annulus into the inside of the apparatus. This view also shows a plug in the lower end of the apparatus to force all fluid in the well below the apparatus into the inside of the apparatus.  
         [0019]    [0019]FIGS. 4 and 4A are a sectional view of the apparatus in FIG. 3 showing the port closed so that pressure may be applied to the inside of the apparatus to force the plug out of the apparatus.  
         [0020]    [0020]FIGS. 5 and 5A are a sectional view of the apparatus in FIG. 4 showing the port closed and a passage opened under the cup seal to allow communication of multiple annuli above and below the cup seal. This view also shows a plug in the lower end of the apparatus to force all fluid in the well below the apparatus into the inside of the apparatus.  
         [0021]    [0021]FIG. 6 is a partial sectional view showing detail of the upper latch shown in the apparatus in FIG. 3.  
         [0022]    [0022]FIG. 6 a  is an external view of FIG. 6.  
         [0023]    [0023]FIGS. 7 and 7A are a sectional view of a hydraulically operated apparatus being run into a well showing the port opened and a cup seal to force the fluid in the annulus into the inside of the apparatus. For simplicity, this view also shows the plug in the lower end of the apparatus removed.  
         [0024]    [0024]FIGS. 8 and 8A are a sectional view of the apparatus in FIG. 6 showing the port closed and a passage opened under the cup seal to allow communication of the annulus&#39; above and below the cup seal. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0025]    Referring to FIG. 1, an embodiment A is illustrated that mounts a seal  10  to the work string  12 . Seal  10  can be any one of a variety of styles but a downwardly oriented cup seal is preferred. Not shown in FIG. 1 is the top end of the work string  12  that is connected to a device described in U.S. Pat. Nos. 3,390,190 or 6,415,862 or another surface mounted device that can connect the top of the work string  12  to separation equipment so the debris can be removed prior to the fluid returning to the mud pit. While the seal  10  is advanced downhole, it cleans the debris from the inner wall  14  of the casing  16 . Fluid in the annular space  18  below seal  10  is forced into the work string  12 , through ports  20 . Any suspended debris or debris scraped from the inner wall  14  goes into the work string  12  as a result of advancement of seal  10 . Annulus  2  above seal  10  can have fluid added into it to compensate for the downhole movement of seal  10  and to prevent high pressure from forming across seal  10 , which could retard the further advance of the apparatus A. The displaced fluid and debris that gets into the work string  12  will be directed through a connection apparatus of the type described in U.S. Pat. Nos. 6,390,190 or 6,415,862 or another device into surface separation equipment of known design (not shown) so that the screened fluid can be returned to the mud pit for future use.  
         [0026]    Also shown are ports  30  and  31 , which can be selectively opened or closed with ports  20  or conversely closed or opened to allow circulation or reverse circulation around seal  10  at any time during the deployment of apparatus A. The importance and operation of these ports will be more fully described later.  
         [0027]    Not illustrated are mechanical devices such as brushes and casing scrapers which may be placed below apparatus A to facilitate removal of solids from the casing wall  14   
         [0028]    [0028]FIG. 2 adds a second apparatus A′ to the assembly shown in FIG. 1 for deployment in wells that have more than one casing size. Illustrated is apparatus A being deployed into casing  16  on work string  12  while apparatus A′ is deployed into liner  16 ′ on work string  12 ′. The transition from casing  16  to liner  16 ′ is shown by use of a seal and anchor system  3  which is often a liner hanger.  
         [0029]    Apparatus A will capture fluid and solids in annulus  18  while apparatus A′ will capture fluid and solids in annulus  18 ′.  
         [0030]    It is understood by those familiar with the art that apparatus A will be attached to a work string  12  which will be a length to position apparatus A near the liner hanger  3 , while the length of the work string  12 ′ will be sufficient to place apparatus A′ near the depth of the liner  16 ′.  
         [0031]    Also shown are ports  30 ,  30 ′,  31  and  31 ′, which can be selectively opened or closed with ports  20  and  20 ′ or conversely closed or opened to allow circulation or reverse circulation around seals  10  and  10 ′ at any time during the deployment of apparatus A and A′. The importance and operation of these ports will be more fully described later.  
         [0032]    Again not illustrated are mechanical devices such as brushes and casing scrapers may be used below apparatus A and A′ to facilitate removal of solids from the casing walls  14  and  14 ′.  
         [0033]    [0033]FIGS. 3 and 3A show one of the preferred embodiments being run into the well casing  16 . The top sub  32  of the apparatus is threaded to the work string  12 . The top sub  32  is threaded to a mandrel  33 , which runs through the apparatus and terminates in a threaded connection to the bottom sub  41 . The top sub  32  and bottom sub  41  are sealed at the mandrel  33  connection with seals  42  and  45  respectively.  
         [0034]    A sleeve  11  is threaded to sleeve  35 . These sleeves have mounted on their exterior, cup seals  10  and  22 , which are supported by thimbles  10 B and  22 B. Though both cup seals, in FIG. 2, are shown facing downward it is apparent either of these seals can be positioned so that at lease one is facing upward. This can be important if circulation around the exterior of the seals is not wanted or if the fluid pressure in the annulus above the seals is higher than the pressure of fluid below the seals.  
         [0035]    These cup seals  10  and  22  are held firmly to the sleeves  11  and  35  by use of the threaded connection  54  between sleeves  11  and  35  so that rotation of mandrel  33  will not rotate sleeve  11  or  35 . The cup seals  10  and  22  are also separated by use of a cup sleeve  10 A.  
         [0036]    Sleeves  11  and  35  are held in an upward position and prevented from rotating by frictional forces between the cups  10  and  22  and the casing wall  14 . As the work string  12  is lowered the mandrel  33  will be urged downward with respect to the cups  10  and  22  until the sleeve  35  shoulders on the lower end  56  of the top sub  32 .  
         [0037]    Should it be anticipated that fluids of a higher pressure may be above the upper cup (one of the cup seals will then be facing upward), the sleeves  11  and  35  may be held in this upward position by threaded fingers  58  on collet  15  (FIG. 6) which is mounded to the mandrel  33  and has threaded fingers  58  (FIG. 6A) engaged into the internal mating threads  15 B (FIG. 6). Should there not be fluids of a higher pressure in the upper annulus there is no need to use the collet  15 .  
         [0038]    It is apparent to those familiar with the art that several apparatus may be run into a well on the same work string as indicated in FIG. 2. Each apparatus would have the same or similar porting arrangement as illustrated in FIGS. 3, 3A.  
         [0039]    As the apparatus is being run into the casing  16  fluid and solids below the seal  22  flow into ports  23  of the sleeve  35  and into ports  25  in the mandrel  33  then to the interior of the mandrel  18  where they flow to the surface where they flow directly to the mud system or separator and filtering equipment (not shown). Seal  42  located on the mandrel  33  isolates ports  19  and  17 . If this is the lowest apparatus in the work string as shown by apparatus A′ in FIG. 1, fluid is prevented from entering the lower end of the apparatus by plug  29  which is sealed to the interior of the mandrel  33  at seal  27  and is held in position by shear screws  37  mounted between the plug  29  and mandrel  33 . Plug  29  assures that all flow is through the ports  23  and  25  to maintain the highest velocity possible in annulus  34 . This will prevent solids from collecting and plugging the annulus  34 . This can be important where a casing scraper and or brushes (not shown) are used below the apparatus. The higher flow will help keep the solids moving through and around this equipment. Should this not be the lowest apparatus in the work string, plug  29  would not be used since flow from the lower apparatus&#39; must move through the work string and all apparatus above and plug  29  would prevent this.  
         [0040]    A collet  40  is also shown at the lower end of the mandrel  33  the purpose of which will be explained later.  
         [0041]    Other devices such as scrapers, brushes, magnets, filters, plug catchers, work string, etc can be attached below the apparatus at threaded connection  49 .  
         [0042]    Referring now to FIGS. 4 and 4A, the apparatus is now shown as it would reach its lower most position in the well bore. At this time it would be desirable to reverse circulate the fluid that is in the work string to the surface since this fluid would contain solids swept from the well as the apparatus is deployed. Reverse circulation defined as moving fluid down the annulus  9  and up the inside of the tubular  18  as shown in FIGS. 5 and 5A.  
         [0043]    To reverse circulate it is necessary to close the ports  23  and  25  and open port  17 . This is accomplished by picking up on the work string  12  at the surface so that the mandrel  33  moves upward relative to sleeves  11  and  35 . In this position seal  37  will isolate ports  25  from  23  closing them and port  17  moves below seal  42  thereby opening port  17 . This will open an annular space  50  located between sleeves  11  and  35  and mandrel  33  forming a flow path between the upper annulus  9  and the lower annulus  34  to allow fluid above the apparatus to flow below the apparatus freely.  
         [0044]    Should the latch  15  be used it would be necessary to rotate the work string  12  as it was being raised to unscrew latch  15  from the mating threads  16  (FIG. 6) in sleeve  11  to allow the mandrel  33  to move upward relative to sleeves  11  and  35 . The same is true for latch  15 ′ except that the work string is rotated as it is being lowered to unscrew latch  15 ′ from mating threads  16 ′ (FIGS. 4 and 4A) in sleeve  35 .  
         [0045]    It is apparent that latches  15  and  15 ′ are not necessary for operation of the apparatus but serve the purpose of locking the apparatus in one of its two positions.  
         [0046]    When the mandrel  33  moves upward until the bottom sub  41  contacts sleeve  35  latch  15 ′ also engages mating latch threads  16 ′ at the lower end of sleeve  35 . This will hold sleeve  35  so that the tool remains in the reversing position. It is understood that the tool can be shifted back to the previous position by lowering the work string  12  while rotating to disengage the latch  15 ′ from its mating threads  16 ′. This will close port  17  and open ports  23  and  25  and engage latch  15  with mating threads  16  as shown in FIG. 6.  
         [0047]    To provide a flow path through the apparatus with ports  23  and  25  closed it is necessary to remove plug  29 . Pressure can now be applied to the interior of the work string  12 . This pressure will apply a force to plug  29  shearing screws  37  thereby releasing plug  29  from mandrel  33  and forcing plug  29  to the bottom of the work well or into a plug catcher sub located at the end of the tool assembly mounted below the apparatus, thus opening the work string.  
         [0048]    Referring now to FIGS. 5 and 5A, the apparatus is now shown in the reverse circulating position. Fluid can now be pumped into annulus  46  (at the surface) through port  17 , through the annular area  50  between mandrel  33  and sleeves  11  and  35 , out port  19  through annulus  34  then into the interior of the tool string  18  back to the surface. Reverse circulating will completely flush all fluid from the well bore replacing it with fluid that is pumped into the annulus at the surface. Again it is understood that there can be other assemblies below the apparatus.  
         [0049]    The arrangement of the sleeves  11  and  35  along with the friction of the cup seals  10  and  22  with the casing  16  provides a method of shifting the tool from the run in position to the reversing position at will.  
         [0050]    In addition the use of the latches  15  and  15 ′ with mating threads  16  and  16 ′ in sleeves  11  and  35  provides a method of not only shifting from one position to the other but locking the apparatus in either of the positions at will.  
         [0051]    Referring again to FIG. 2, should this be the upper assembly A in a tool string such that the fluid moving through the annulus  9 ,  9 A and  28  will progress to the bottom assembly A′ then into the interior of the work string  12 .  
         [0052]    Referring now to FIGS. 7 and 7A, another embodiment is shown with a top sub  51  attached to the work string  12 . Inside the top sub  51  is a sleeve  52  sealed in the top sub  51  by seals  53  and  54 . A shifting sleeve  55  is located inside the sleeve  52  and is sealed in the sleeve  52  by seals  56  and  57 . The shifting sleeve  55  is also secured to the sleeve  52  and by shear screws  77 . Annulus pressure is vented through port  60  to an annular space  61  between top sub  51  and sleeve  52 , this pressure is then vented to the annular space  63  through port  62  where it operates on surface  59  of shifting sleeve  55 .  
         [0053]    This upper portion of the apparatus forms a hydraulic system with pressure inside the work string  12  operating on the upper portion of the shifting sleeve  55  at surface  58  and pressure in the annulus  9  working on the lower side of the shifting sleeve at surface  59 .  
         [0054]    Top sub  51  is attached to mandrel  64 . A number of cup seals  65 , 66 , and  67  are mounted on mandrel  64  and supported by thimbles  68 , 69  and  70  and held in place by cup spacers  71  and  72  while being secured to the mandrel by cup sleeve  73 . The cup seals, thimbles, cup spacers and cup sleeve components are secured by the bottom sub  74 , which is connected to the lower end of the mandrel  51 .  
         [0055]    If this is the lower apparatus such as A′ in FIG. 2 a plug  29  can be secured to the bottom sub  74  by shear screws  37 . Seal  27  also seals the plug  29  inside the bottom sub  74 .  
         [0056]    Other devices such as scrapers, brushes, magnets, filters plug catcher subs etc can be attached below the apparatus at threaded connection  49 .  
         [0057]    As indicated by arrows  28 , as this apparatus is lowered into the casing  16  by the work string  12  solids adhering to the casing wall  14  and fluids below the cup seals are directed into the work string  12  through ports  75  and  76  located in the cup sleeve  73  and mandrel  64 . Fluid is prevented from entering annular space  78  located between mandrel  64  and shifting sleeve  55  by seals  79 . Thus fluid is directed through the work string  12  to the surface where it can flow to the mud or filter system.  
         [0058]    After reaching the desired depth, application of surface pressure to the interior of the work string  12  will first shear screws  27  forcing plug  29  out the bottom of the assembly to the bottom of the well or into a plug catcher sub (not shown) located at the end of all devices below the lowermost apparatus in the work string (this apparatus), secondly this pressure will shear screws  77  allowing shifting sleeve  55  to move downward until it contacts bottom sub  74 . As this movement occurs seals  79  are moved below port  76  opening ports  75  and  76  to the annular space  78  between the mandrel  64  and shifting sleeve  55  thereby opening a path through port  80  to the annulus above the upper cup seal  65 . Prior to the shifting sleeve  55  contacting the bottom sub  74  surface  83  of the shifting sleeve will open “C” ring  84 . When shifting sleeve  55  contacts bottom sub  74  “C” ring  84  will snap into grove  82  of shifting sleeve  55 . This “C” ring  84  will hold shifting sleeve in this position. With this arrangement the shifting sleeve once shifted cannot be returned to its original position.  
         [0059]    Now referring to FIGS. 8 and 8A, as shown by arrows  81  reverse circulation can now occur by pumping fluid into the annulus between the casing  16  and work string  12  at the surface. This fluid will then be directed through ports  80 , annular spaces  78  and ports  75  and  76  of all such devices in the well to the lower most end of all devices where it will enter the interior of the work string  12  to be directed to the surface and back to the mud or filter system.  
         [0060]    The foregoing disclosure and description of the invention are illustrative and explanatory thereof, and various changes in the size, shape and materials, as well as in the details of the illustrated construction, may be made without departing from the spirit of the invention.

Technology Classification (CPC): 4