Patent Publication Number: US-2012031611-A1

Title: Erosion Migration Arrangement, Erodable Member and Method of Migrating a Slurry Flow Path

Description:
BACKGROUND 
     A known issue that occurs along a slurry flow path is erosion of components. For example, the flow of gravel slurry during downhole gravel packing operations in the downhole completion industry have been known to erode completely through a wall of a casing. Operators have employed various techniques to minimize such erosion including use of hardened shields in the most erosion prone locations. Such methods may successfully address the erosion concern, however, positioning the hardened shields often comes at a cost premium. Other drawbacks may also be encountered, such as difficulty in properly positioning the shields, for example. Operators are therefore always interested in new devices and methods to address undesirable erosion. 
     BRIEF DESCRIPTION 
     Disclosed herein is an erosion migration arrangement that includes a tubular having a window therein. A body positioned within a portion of the window is configured to sacrificially erode in response to a slurry flowing through the window to thereby migrate a location of impact on a member positioned downstream of the window. 
     Further disclosed is a method of migrating a slurry flow path including constructing at least one portion of a border of a window of a tubular from an eroded material, flowing slurry through the window; eroding the at least one portion at a faster rate than a remaining border of the window; and migrating a flow path of the slurry. 
     Further disclosed is a sacrificially erodable member which includes a core configured to easily erode in a target environment, and a shell in operable communication with the core configured to protect the core from eroding until fracture thereof. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The following descriptions should not be considered limiting in any way. With reference to the accompanying drawings, like elements are numbered alike: 
         FIG. 1  depicts a cross sectional view of an erosion migration arrangement disclosed herein prior to being eroded; 
         FIG. 2  depicts the cross sectional view of the erosion migration arrangement of  FIG. 1  after being partially eroded; and 
         FIG. 3  depicts an erodable body disclosed herein. 
     
    
    
     DETAILED DESCRIPTION 
     A detailed description of one or more embodiments of the disclosed apparatus and method are presented herein by way of exemplification and not limitation with reference to the Figures. 
     Referring to  FIGS. 1 and 2 , an erosion migration arrangement is disclosed generally at  10 . The erosion migration arrangement  10  includes, a tubular  14  having at least one window  18  through a wall  20  thereof, and a body  22  positioned within a portion of the window  18 . The body  22  is configured to erode in response to a slurry flowing through the window  18  at a faster rate than portions of the window  18  that do not include the body  22 . The erosion of the body  22  thereby causes a flow path  26  of the slurry to migrate in a direction of the erosion. This migration has a beneficial effect of lessening a depth of erosion of a surface  30  positioned downstream of the window  18  by moving an area of impingement  34 . This affect is illustrated by the positional change (in a rightward direction in the Figures) observed between the area of impingement  34  shown in  FIG. 1  and that shown in  FIG. 2 . In this embodiment, erosion of the body  22  has caused a longitudinal dimension  38  of the window  18  to increase from that shown in  FIG. 1  to that shown in  FIG. 2 . In a downhole gravel packing application, for example, the erosion migration of the surface  30  of a casing can prevent eroding completely through a wall  42  thereof. 
     The body  22 , as described, sacrificially erodes to intentionally alter the area of impingement  34  on the downstream surface  30 . Specifically selecting certain design parameters can influence this intentional sacrificial erosion. For example, a border location of a portion of the window  18  having the body  22  can influence the rate of erosion thereof. Positioning the body  22  on a downhole portion of the border will assure that more of the particulates in the slurry directly impact the body  22  and with greater force than if the body  22  is placed elsewhere along the border. Alternately, the body  22  can have an altered geometry that is susceptible to erosion, such as a thinner wall, for example. Additionally, the body can be made of a material that erodes more easily than a material from which the tubular  14  is made. Alternately, the body  22  could be made of the same material as the tubular  14  but be processed in differently. For example, the body could be foamed or heat-treated resulting in a different strength and hardness. 
     Referring to  FIG. 3 , an alternate embodiment of a body  50  disclosed herein is illustrated. The body  50  includes a core  54  encapsulated by a shell  58 . The shell  58  can be made of a stronger material than the core  54  thereby allowing erosion to accelerate once the shell  58  has fractured. In some embodiments the core  54  can be a material that disintegrates when exposed to certain environments. For example, materials that disintegrate when exposed to changes in temperature or pressure or to specific fluids, could be employed to accelerate degradation of the material properties and quicken a rate of erosion. In downhole applications reactive metals such as Mg, Al, Zn, Sn and alloys including at least one of the foregoing, can react with wellbore fluids to control a rate of disintegration or corrosion. The shell  58  in such an application may be a micro or nano-scale coating consisting of metallic, intermetallic, ceramics, oxides, carbides and nitrides, for example, to provide further control over exposure of the core  54  and subsequent disintegration thereof. Additionally, micro or nano reinforcing particulates can be dispersed within the core  54  to provide a further level of erosion control. In these cases, the shell  58  prevents any premature disintegration of the core  54  by limiting exposure of the core  54  to the environment until slurry flow has begun and the shell  58  has been breached. The slurry also could include chemicals, such as an acid, for example, that will accelerate degradation of the core  54  as well as the shell  58 . 
     While the invention has been described with reference to an exemplary embodiment or embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the claims. Also, in the drawings and the description, there have been disclosed exemplary embodiments of the invention and, although specific terms may have been employed, they are unless otherwise stated used in a generic and descriptive sense only and not for purposes of limitation, the scope of the invention therefore not being so limited. Moreover, the use of the terms first, second, etc. do not denote any order or importance, but rather the terms first, second, etc. are used to distinguish one element from another. Furthermore, the use of the terms a, an, etc. do not denote a limitation of quantity, but rather denote the presence of at least one of the referenced item.