Abstract:
An outlet member is preferably made from a hardened material and is cut from a tubular shape at an angle of preferably 5 degrees. At its upper end it is cut away so that slurry flow can exit ports in a hardened sleeve and impinge directly onto the upstream portion of the insert. The impingement changes the flow stream angle as the flow continues through a fully tubular middle segment of the insert that leads out to an elongated exit ramp whose downstream end sits preferably flush with the outer housing wall so as to protect the insert from mechanical shocks and retain the insert axially when slurry flows through it. Other external details aid in fixation when in use.

Description:
FIELD OF THE INVENTION 
     The field of this invention is completion tools for subterranean use and more particularly those tools used in gravel packing and fracturing subterranean locations and designs to minimize erosion damage from slurries flowing through and entering an annular space around the tool. 
     BACKGROUND OF THE INVENTION 
     Well completions that need sand control involve a series of screens with an isolation packer above and a crossover tool that extends through a bore in the packer mandrel that allows gravel slurry to be delivered through the tubing and ultimately into the annular space around the screens as the carrier fluid returns to the surface through the crossover tool and up the outer annulus above the production packer. The path for the delivered gravel slurry is through a first series of ports to get out through the tubing and then into an annular space defined around the tubing by the packer skirt or lower extension assembly. The slurry then exits ports in the packer skirt to get to the annulus around the screens in the producing zone. The erosive nature of the gravel slurry causes excessive wear at the ports both at the tubing and at the packer skirt opening. 
     Prior efforts at controlling such damage from erosion included placing of hardened inserts in openings in softer metal components to protect the edges of the openings in the softer metal as shown in U.S. Pat. No. 6,491,097. Earlier a hardened sleeve with ports that overlay ports in a weaker surrounding housing were used to prevent erosion of the openings in the surrounding housing as shown in U.S. Pat. No. 5,636,691. Other solutions attempted to configure the flowing stream into a circular or helical pattern to reduce the erosion from impact of slurry that exited ports in a housing. This feature can be seen in U.S. Pat. No. 7,185,704. Other designs used a pivoting baffle plate that responded to slurry flow stream impact to redirect it away from an opposing casing wall as shown in U.S. Pat. No. 7,559,357. Other designs to reduce erosion involved a spinning member that received impact of the slurry flow and was caused to spin to take the energy out of the flowing slurry stream while protecting the housing wall behind the spinning member as described in U.S. Pat. No. 7,096,946. A stationary component with a spiral ridge or projection to induce swirl in the slurry flow is shown in US Publication 20090301710 A1. 
     Some of the offered designs in the past had moving parts that presented mechanical reliability issues in slurry service. Others put openings in hardened sleeves or hardened inserts directly adjacent to openings in the softer metal housings in an effort to protect the edges of the softer metal by making smaller holes in the hardened sleeve or inserts in the openings in the wall of the softer metal. This also caused resistance to flow so that higher slurry velocities occurred or the drift diameter through the tool was reduced. To avoid the issues with the above described prior designs, the present invention seeks to provide in a design with no moving parts a path for the slurry that redirects its flow direction in the course of spacing apart the soft metal components from the hardened flowpath that reorients the slurry stream. By getting the slurry to travel along the insert in a nearly parallel orientation, the housing walls are protected from any severe erosion as opposed to the prior efforts described above where the slurry exited in intimate contact with the edges of openings in the softer metal of a surrounding housing. Applications for a crossover housing and a subsequent outlet to an annular space around the screens are contemplated. These and other aspects of the present invention will become more readily apparent to those skilled in the art from a review of the description of the preferred embodiment and the associated drawings while appreciating that the full scope of the invention is determined by the appended claims. 
     SUMMARY OF THE INVENTION 
     An outlet member is preferably made from a hardened material and is cut from a tubular shape at an angle of preferably 5 degrees. At its upper end it is cut away so that slurry flow can exit ports in a hardened sleeve and impinge directly onto the upstream portion of the insert. The impingement changes the flow stream angle as the flow continues through a fully tubular middle segment of the insert that leads out to an elongated exit ramp whose downstream end sits preferably flush with the outer housing wall so as to protect the insert from mechanical shocks and retain the insert axially when slurry flows through it. Other external details aid in fixation when in use. Applications in a crossover housing and in a surrounding housing before reaching the annulus outside of a screen assembly are contemplated. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a section view of the inserts assembled around a hardened sleeve; 
         FIG. 2  is a view of a single insert; 
         FIG. 3  is an exterior view of a mounted insert under a cover sleeve and extending beyond the cover sleeve; 
         FIG. 4  is a section view from within the hardened sleeve to show the upstream end of the insert; 
         FIG. 5  is an exterior housing view at the discharge end of the insert showing that end protected in a housing recess; 
         FIG. 6  is a part section close up view of the inlet of the insert showing various fixation devices to hold the inlet in place; and 
         FIG. 7  shows the tubularly shaped transition portion of the insert. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring to  FIG. 2  the insert  10  has an inlet portion  12  leading to a transition portion  14  and ending with an outlet portion  16 . The insert  10  starts as a tubular shape or a block and then is preferably cut into the illustrated shape using wire EDM techniques after sintering the carbide or simply grinding before sintering. It can be one piece or in several pieces. The slant cut is preferably at 5 degrees but a range of angles is contemplated that is controlled primarily by the space available, as seen in  FIG. 1 , along and below the hardened sleeve  18  that preferably has axial rows of openings  20  that are circumferentially spaced with each insert  10  positioned so that its inlet portion  12 , which comprises a portion of the formerly tubular or block shape located in radial juxtaposition to a row of openings or slots or any other shape or shapes  20 . The size and mounting angle of the insert  10  is also dependent on the thickness of housing  32 . The flowing stream through the insert  10  is preferably on an axis that is no more than 5 degrees from the axis of the housing  32  although other ranges from a few degrees, such as 2 degrees to the slant of the openings or ports  20  is contemplated. In the preferred embodiment the openings  20  in a given row are themselves cut on an axis of about 20 degrees, although a broader range such as about 10-45 degrees is contemplated. Alternatively, the openings  20  can be radial if the inlet portion is made thick enough to withstand nearly perpendicular slurry impact flow. The inlet portion  12  has an arcuate or flat or another shape or shapes inner wall  22  with one of its side edges  24  and  25  visible in  FIG. 6  and both inner edges  24  and  25  visible in  FIG. 6 . If the insert is made from an initial solid rectangular block the profile of wall  22  does not need to be arcuate. It can have other shapes such as flat. While  FIG. 6  shows a clearance from edges  24  and  25  to the sleeve  18  to facilitate assembly, a close fit is also envisioned such as a clearance fit or even a small amount of interference. The opposite side edge that is not seen is on an opposite side of a row of openings from edge  24  such that the exiting flow of slurry represented by arrow  26  goes through the rows of openings  20  where the hardened material of the sleeve  18  protects the edges  28  that define the openings  20 . The opposed edges  24  and  25  span a row of openings  20  and then by the nature of the angular cut to the original tube or block that formed the insert  10 , converge toward each other as the transition portion  14  is reached. While rows of openings  20  are illustrated, elongated slots can be used in the alternative. This is best shown in  FIG. 6 . However, in the region of the row of holes  20  the opposed edges of the insert  10  at the inlet portion  12  are further apart than the hole dimension so that a passage  30  is defined outside the sleeve  18  as the transition potion  14  is reached, as best seen in  FIG. 2 . 
     The housing  32  has a series of parallel ribs  34  that are on the outside of the sleeve  18  and located between rows of holes  20 . These ribs have lower end shoulders so that a pair of ribs  34  presents spaced locating shoulders  36  and  38  on which the inlet portion  12  is supported. Ribs  34  have an outer ridge  40  to serve as a travel stop for cover sleeve  42 . Ribs  34  also have an external groove  44  in which sits an o-ring or clamp, snap ring or other fastener  46  that abuts the outer wall  48  of inlet segment  12 . This is best seen in  FIGS. 3 and 7 . 
     Slant cut  50  is on the transition portion and it is put there to allow the transition portion  14  to fit up to the inside surface of the cover sleeve  42  as compensation for the slant mounting of the insert with respect to the axis of the housing  32 . The transition portion  14  is further defined by a 360 degree structure along a plane defined by the outlet surface  52 . The top  54  of surface  52  is preferably located axially even with or below the lower end of sleeve  42  but not further out radially than sleeve  42  so that the exiting slurry flow will not directly impact the sleeve  42  even if there are small eddy streams as the main body of the flow continues toward the outlet portion  16 . 
     Referring to  FIG. 4  it is noted that that lowermost outer location  51  of the transition portion  14  extends radially further from the axis  55  of the assembly than the lower end  53  of the insert  10  outlet  16 . With this configuration, the flowing slurry stream has the ability to fan outwardly after passing location  51  so as to lessen the impact on the surrounding tubular or casing while still affording protection to the housing exterior at  70  which is disposed parallel or near parallel to the contact surface  72  on the outlet portion  16  better seen in  FIG. 2 . The transition portion extends at the lower end to a plane through location  51  that is perpendicular through the flow axis  57 . The other end of the transition portion is through location  59  where the insert  10  is closest to the sleeve  18  near the uphole end of the surface  72  and also in a plane perpendicular to axis  57 . 
     Depending on the position of the lowermost opening  20  with respect to the transition  56  of edges  24  and  25  it may or may not be possible for a flow stream to go straight out of the opening defined by surface  52  without making a turn. Preferably, the lowest hole  20  is far enough above the transition  56  so that all flow out of the openings  20  impacts the inlet portion  12  and turns to align with the opening defined by surface  52  at the transition portion  14 . 
     The exit portion  16  continues from transition portion  14  with opposed edges  58  and  60  that end at lower end  62 . Lower end  62  is in a recess  64  that has a lower end  66  and acts as a lower travel stop for the insert  10 . As seen in  FIG. 4 , the upper portion  12  is up against vertical flat surface  68  between ribs  34  as also seen in  FIG. 6 . The o-ring  46  also wedges the upper portion against shoulders  36  and  38  using the cover sleeve  42 . It is preferred that the lower end  62  does not protrude radially out of recess  64  to protect it against mechanical shocks but some radial extension is acceptable at lower end  62  since the cover sleeve  42  is close by and has a larger dimension. Cover sleeve  42  is radially smaller than stops  40 , below, and some portion of the housing  32 , above. Housing  32  has a taper  70  that preferably aligns the taper with the inner curved, flat or some other shape or shapes of wall  72  of the outlet portion  16 . What slurry impingement occurs at this location is at such a slight angle that the erosion in that location does not affect the performance of housing  32 . 
     Sleeve  18  has a non-hardened extension sleeve  74  so that the two can be shifted in tandem to close the slurry openings in the housing  32  by positioning the sleeve  74  opposite the ribs  34 . 
     In the preferred application of the insert  10  an array is located around a hardened sleeve  18  which defines an annulus around the exit of a crossover tool for gravel packing. The housing  32  is part of the lower extension sleeve of a packer also not shown but the arrangement of these accessory components is known to those skilled in the art. An array of inserts  10  is disposed under the cover  42  of the housing  32 . In another application the array of inserts  10  can be located in wall openings of a crossover housing. 
     The construction of the insert allows for a gravel or other slurry exit path that avoids impinging softer surrounding surfaces as the insert  10  has an inlet portion  12  that collects the slurry stream exiting hardened openings and defines a hardened path about said openings  20  to funnel the slurry flow through the transition portion  14  where the angle of the flow with respect to the surrounding housing  32  axis is very small and preferably in the range of about 5 degrees but can vary from about 2-20 degrees. While the passage size and housing dimensions can dictate the length of the insert  10  its slope with respect to the housing axis of housing  32  should not exceed the slope of the cut for the openings  20 . The slight angular exit from the inserts  10  and the presence of the outlet portion  16  further protects the soft components of housing  32  from impingement of the slurry stream and what impingement there is occurs at such a small angle of contact that even high slurry flows such as 70 barrels per minute, with flow variable depending on the application size, do not create erosion that is of any concern. Thus the outlet from the surrounding housing such as  32  is spaced apart from the openings  20  in the interior structure  18  such that the insert can be shaped to create a flowpath that is resistant to erosion while reorienting the flowing slurry stream. Using the outlet portion  16  the exterior structure such as surface  70  is protected from erosive action because the slight angular exit angle of the insert  10  allows the slurry flow to be nearly parallel to the outer housing so that the impact angle is at a minimum and further directs the slurry into the annulus and down to the region of the gravel screens without significant erosive contact with a surrounding casing when it is a cased hole that is being gravel packed or fractured. When used in an application such as a crossover housing the small exit angle can reduce or eliminate the need for a blast liner in a surrounding housing as the erosive effects will be attenuated or even eliminated. While the preferred application is screen frac packing for sand control, other subterranean applications are contemplated where the flowing stream is capable of erosion. 
     The preferred material for the insert  10  is tungsten carbide although other hard materials that resist erosion from slurries are contemplated. 
     The above description is illustrative of the preferred embodiment and many modifications may be made by those skilled in the art without departing from the invention whose scope is to be determined from the literal and equivalent scope of the claims below.