Abstract:
A permeable material compacting method includes, forming a cavity between a membrane and a structure, porting fluid to or from the cavity, positioning permeable material adjacent the membrane, generating a differential pressure across the membrane, deforming the membrane, and decreasing volume of the permeable material

Description:
BACKGROUND 
       [0001]    Gravel packing is a process used in the downhole industry to fill an annulus with gravel. Gravel packed by such a process is permeable to fluid while providing support to walls of a wellbore in an earth formation, for example. The support prevents erosion and other damage to the formation walls that could result if the gravel support were not present. Recent developments replace the gravel pack with permeable space conforming materials that can expand to fill an annulus after being deployed therein. Such materials, as those described in U.S. Pat. 7,828,055 granted to Willauer et al. on Nov. 9, 2010, in U.S. Pat. 5,049,591 to Kaisha on Sep. 17, 1991 and methods as described in U.S. Pat. 7,644,773 to Richard on Jan. 12, 2010, the entire contents of which are incorporated herein by reference, require compaction or compression prior to being deployed. Methods and systems for compacting such materials are well received in the art. 
       BRIEF DESCRIPTION 
       [0002]    Disclosed herein is a permeable material compacting method. The method includes, forming a cavity between a membrane and a structure, porting fluid to or from the cavity, positioning permeable material adjacent the membrane, generating a differential pressure across the membrane, deforming the membrane, and decreasing volume of the permeable material. 
         [0003]    Further disclosed herein is a permeable material compacting apparatus. The apparatus includes, a structure, and a membrane in operable communication with the structure defining a cavity therebetween. The membrane is deformable to allow a differential pressure to be built thereacross to cause a volume of the cavity to change, the membrane is also configured such that permeable material positioned adjacent the membrane can be compressed to a smaller volume in response to deformation of the membrane. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0004]    The following descriptions should not be considered limiting in any way. With reference to the accompanying drawings, like elements are numbered alike: 
           [0005]      FIG. 1  depicts a partial cross sectional view of a permeable material compacting apparatus disclosed herein; and 
           [0006]      FIG. 2  depicts a partial cross sectional view of an alternate embodiment of a permeable material compacting apparatus disclosed herein. 
       
    
    
     DETAILED DESCRIPTION 
       [0007]    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. 
         [0008]    Referring to  FIG. 1 , an embodiment of a permeable material compacting apparatus disclosed herein is illustrated at  10 . The permeable material compacting apparatus  10  includes a structure  14 , shown in this embodiment as a mandrel or tubular, and a membrane  18 . The membrane  18  is sealably attached to the structure  14  at ends  22  and  26  defining a cavity  30  between the membrane  18  and the structure  14 . A fitting  34  fluidically connects a conduit  38  to the membrane  18  so that fluid can be pumped into and out of the cavity  30 . It should be noted that the fitting  34  could alternately be positioned in the structure  14  thereby allowing fluid transfer to and from the cavity  30  through the structure  14 . Permeable material  42  placed within the cavity  30  can be compacted in response to a vacuum being pulled in the cavity  30  through the conduit  38  that creates a differential pressure across the membrane  18  and urges the membrane  18  to deform and the volume of the cavity  30  to decrease. Heating the permeable material  42  before compaction and cooling the permeable material  42  after the compaction can aid in increasing the percentage of volume reduction of the permeable material  42  and maintaining it in the reduced volume condition until volumetric expansion is again desired. 
         [0009]    It should be understood that the term permeable material as used herein covers any material that could serve as a filter to remove unwanted particulates from fluid passing therethrough. This filtration can be via flow through pores, cells or interstices, for example and as such, materials employable as the permeable material  42  include porous or cellular materials as well as membranes, mats and foams. 
         [0010]    Referring to  FIG. 2 , an alternate embodiment of a permeable material compacting apparatus disclosed herein is illustrated at  110 . The permeable material compacting apparatus  110  is similar to that of apparatus  10  and as such like elements are identified with the same reference characters. A primary difference between the apparatus  110  and  10  is the addition of an autoclave  146  configured to house at least the permeable material  42 , the membrane  18  and the structure  14 . The autoclave  146 , in this embodiment, includes a cylindrical portion  150  with end caps  154  sealably attached thereto, but may in practice be any pressure vessel structure with appropriate closures. One or more fittings  158  (with two being illustrated) provide fluidic access to a cavity  162  defined between the vessel  146  and the membrane  18  and the structure  14 . The structure  14  of this embodiment includes fluid tight end caps  166  with the fitting  34  connecting the conduit  38  through one of the end caps  166 . The conduit  38  also sealably extends through the end cap  154  through a fitting  36 . The conduit  38  may just as well pass through the wall  150  of the autoclave  146 , using fittings or connectors similar to fitting  36 , for example. Additionally, one or more ports  170  in the structure  14  provide fluidic communication between the cavity  30  and a cavity  32  and thence to the conduit  38 . 
         [0011]    The autoclave  146  allows pressure to be built therewithin to assist in or singly provide the differential pressure across the membrane  18  that causes deformation of the membrane  18  and compression or compaction of the permeable material  42 . Stated another way, the apparatus  110  can employ one or both of pressure in the cavity  162  and vacuum in the cavity  32  to create the desired pressure differential across the membrane  18 . In applications wherein the only pressure is built within the cavity  162 , the ports  170  serve as a vent to allow fluid within the cavity  30  to escape when volume of the permeable material  42  is being reduced. This vented fluid from the cavity  30  can flow into the cavity  32  and then to the ambient atmosphere through the conduit  38 . 
         [0012]    By at least two of the fittings  158  providing fluidic access to the cavity  162 , fluid, such as water or oil, for example, at temperatures different than that of the permeable material  42  can be pumped into and out of the vessel  146  to expedite transferring heat to and from the permeable material  42 . As such, temperatures of the permeable material  42  can be adjusted before and after creation of differential pressure across the membrane  18  and subsequent compaction of the permeable material  42  takes place. While some materials usable as the permeable material  42  are preferably heated before compaction and cooled after, as discussed above, for other materials the heating and cooling order are reversed. Some high-loft materials, which, as initially assembled, are largely void, such as high-loft fiber mat, for example, in order to serve their purpose downhole must be consolidated or compacted into a more dense layer. Additionally, some materials, while held in the consolidated or compacted arrangement require that the temperature of the fiber be raised to a determined temperature. Such materials are sometimes referred to as heat fusible mats. These materials may be compacted while cold, and then heated to a determined temperature to fuse them. 
         [0013]    Additionally, some materials, when placed in the cavity  30  for subsequent compaction, achieve a non-uniform surface configuration, with greatly varying thickness from place to place. This is especially the case when the structure  14  and the permeable material  42  are both cylindrical. One way to improve geometric uniformity during this process is to prepare the permeable material  42  by placing a tension film  19  over the material after installing it on structure  14  and before covering it with the membrane  18 . The film  19  material is chosen to provide compressive stress on the permeable material  42  from its initial configuration to its final configuration. In one embodiment, a natural rubber membrane capable of stretching to 3-7 times its initial length is chosen for the film  19  material. The film  19  is wrapped around the permeable material  42  while the film  19  is stretched 3-7 times its initial length. The film  19  is then fixed in position using adhesive tape or other means. The membrane  18  is placed around the film  19  and the process described above is performed. The residual tension in the film  19  influences the permeable material  42  to take a more uniform cylindrical shape in lieu of hills and valleys that tend to form when membrane  18  is used alone. 
         [0014]    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.