Abstract:
A particulate exculder tool includes a basepipe having one or more retention features; a screen jacket disposed radially outwardly of the basepipe; one or more end housings at the screen jacket; and a deformable element disposed between a portion of the one or more end housings and one or of the one or more retention features and method.

Description:
BACKGROUND 
     In many downhole fluid production wells, particulate matter production is to be avoided. In view hereof, “sand screens” are often used to exclude particulate matter from fluidic components entering the production apparatus. Sand screens sometimes include a holed base pipe, a filtration medium and a shroud. The filtration medium and shroud are often preassembled as a jacket before installation thereof on the holed base pipe. In order to enhance life of service of the production well and particularly as the wells get deeper, it is common to use higher alloy steels in the base pipe. While this material does indeed present excellent resistance to abrasive degradation, it also promotes an ancillary problem. The problem is related to the method commonly used for attachment of the jacket to the base pipe. Generally, the favored attachment means is by welding. Welding high alloy materials, while being effective from an affixation standpoint, also may cause the high alloy material to corrode more readily. Since wellbore environments are naturally highly corrosive, the drawback associated with welding as noted is particularly detractive. 
     In view of the foregoing, the art would welcome screen jacket coupling methods and apparatus that avoid welding thereby avoiding the foregoing effects and additionally avoiding, generally necessary, heat treating operations after welding to stress relieve and temper the final product. 
     SUMMARY 
     A particulate exculder tool includes a basepipe having one or more retention features; a screen jacket disposed radially outwardly of the basepipe; one or more end housings at the screen jacket; and a deformable element disposed between a portion of the one or more end housings and one or of the one or more retention features and method. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Referring now to the drawings wherein like elements are numbered alike in the several Figures: 
         FIG. 1  is an illustration of a well tool having a screen coupled thereto according to the disclosure herein. 
         FIG. 2  is an enlarged view of a circumscribed portion of  FIG. 1  taken along circumscription line  2 - 2 . 
         FIG. 3  is a view of a longitudinal groove or spline pattern; 
         FIG. 4  is a view of a helical groove pattern. 
     
    
    
     DETAILED DESCRIPTION 
     Referring to  FIGS. 1 and 2  simultaneously, a particulate matter exclusion tool or sand screen  10  is illustrated. 
     The tool  10  includes a base pipe  12  having at least one undercut, and illustrated with retention features such as undercuts  14  and  16  (undercut  14  illustrated in enlarged form in  FIG. 2 ). Each undercut  14  and  16  preferably provides a shoulder uphole and downhole of the undercut. Shoulders  18  and  20  are illustrated in  FIG. 2  for undercut  14  and it shall be understood that similar shoulders are provided at undercut  16 , though not visible without enlargement as in  FIG. 2 . Each undercut is in one embodiment at least about 0.060 deep so that the shoulders bear that measurement. Reasoning for this will become apparent hereunder. It will be appreciated that this is the component of the screen likely to be composed of a high alloy metal and therefore sensitive to welding. 
     Disposed about the base pipe  12  is a screen jacket  22 , (a sand exclusion device) which screen is configured to exclude particulate matter having dimensions greater than a predetermined set of dimensions. Such screen jacket is in one embodiment configured as noted above to have a filter medium  24  and a shroud  26 . The jacket  22  is substantially the same as screen jackets on commercially available sand screens from Baker Oil Tools, Lafayette, La. and therefore requires limited discussion here. 
     The screen jacket disclosed herein includes end housings  28  and  30  that are configured with a first inside dimension at numeral  32  and  34 , respectively, and a second inside dimension at  36  and  38 , again respectively. In each case, the first inside dimension is selected to closely clear an outside dimension of the base pipe  12  while the second inside dimension is selected to be spaced from the outside dimension of the base pipe  12  by an amount sufficient to accept a deformable element (which may in some configurations be both a mechanical attachment and a seal and in other configurations represent less than 360 degrees of contact with the base pipe such that the deformable element acts only as a mechanical attachment)  40  in clearance relationship therewith where the element  40  is in an unactuated condition and in an interference relationship when the element is in an actuated condition. For purposes of clarity of disclosure, the space defined by the second inside dimension of the end housings and the base pipe will be referred to herein as pockets  42  and  44 . Pockets  42  and  44  are to be aligned axially with undercuts  14  and  16 , respectively so that seals  40  disposed within pockets  42 / 44 , when activated, contact each undercut. Further, each end housing  28  and  30  includes a box thread  46  and  48 , respectively, which is to threadably receive a collar  50  and  52 , respectively. Collars  50  and  52  thread into their respective end housings  28  and  30  to reduce the axial dimension of pockets  42  and  44 . By reducing this axial dimension, with the element  40  installed therein, the element is caused to deform both radially inwardly and radially outwardly into contact with undercuts  14  and  16  and, respectively, the second inside dimension of each end housing  28  and  30 . By so deforming the element, the screen jacket  22  is mechanically locked in place without the need for welding to the basepipe. Further the post heat treatment generally required after such a welding operation is avoided saving both cost and time. 
     In one embodiment, the element  40  is a metal element and may be a mini z seal commercially available from Zeroth Technology Limited. 
     As is visible in  FIG. 2 , element  40  is in the activated position and extends into the undercut  14 . Depending upon the amount of axial compression of element  40  from collar  50 , the element may move axially until contacting one of shoulders  18  or  20 , or indeed may be frictionally affixed wherever it made contact with the undercut when activated. Further, in another embodiment, the retention features include the frictional coefficient of the basepipe at the undercuts or at the same location without undercuts. The frictional coefficient may be enhanced by surface preparation thereof such as by knurling (eg. to create grooves), roughening, splining, or other surface treatment as shown in  FIGS. 3-4 . Such treatments will improve not only axial retention of the screen jacket but rotational retention as well. In yet another embodiment, the surface treatment is sufficient to provide the needed retention against the elements  40  so that undercuts are not required. It is also to be understood that the undercuts could be substituted for by an upstruck member at the outside dimension of the base pipe against which the element  40  can bear with the same effect of anchoring the screen providing that a greater clearance at the end housings is provided so that the screen can be installed thereover. 
     While preferred embodiments have been shown and described, modifications and substitutions may be made thereto without departing from the spirit and scope of the invention. Accordingly, it is to be understood that the present invention has been described by way of illustrations and not limitation.