Patent Document

This application claims the benefit of U.S. Provisional Application 60/522,133, filed Aug. 19, 2004. 

   BACKGROUND OF THE INVENTION 
   1. Field of Invention 
   The present invention pertains to conveyance devices, and particularly to conveyance devices to bypass a section of a wellbore. 
   2. Related Art 
   Gravel packing is often performed in wells having loose or poorly consolidated formations. The gravel placed in the wellbore serves as a filter to prevent the production of sand or fines from the formations. However, for various reasons the gravel packing operation may leave voids in the gravel pack, leading to the undesired sand production. 
   SUMMARY 
   The present invention provides for a conveyance device to bypass regions within a wellbore that may disrupt the desired distribution of gravel in a gravel pack. 
   Advantages and other features of the invention will become apparent from the following description, drawings, and claims. 

   
     DESCRIPTION OF FIGURES 
       FIG. 1  is a schematic view of wellbore with a service tool therein having a conveyance device in accordance with the present invention. 
       FIG. 2  is a schematic view of an alternative embodiment of the conveyance device of  FIG. 1 . 
   

   DETAILED DESCRIPTION 
   Referring to  FIG. 1 , a wellbore  10  is shown having an upper horizontal section  12  and a lower horizontal section  14 . A casing  16  lines upper section  12  and lower section  14  is shown as an open hole, though casing  16  could be placed in lower section  14  as well. To the extent casing  16  covers any producing formations, casing  16  must be perforated to provide fluid communication between the formations and wellbore  10 . 
   A packer  18  is attached to an upper tubular  20 , and generally run into wellbore  10  until properly positioned and set near the lower end of upper section  12 . When packer  18  is set, it engages and seals against casing  16 , as is well known in the art. Packer  18  has an extension/crossover  21  to which other lower completion equipment such as a conveyance device  22  and a screen  24  can attach. Screen  24  is preferably disposed adjacent a producing formation in lower section  14 . 
   In the embodiment of  FIG. 1 , conveyance device  22  is an inner tubular within an outer tubular forming an annular flow path between the inner and outer tubulars. The inner and outer tubulars may be concentrically or eccentrically aligned axially and held apart using conventional means such as spars or spacers. A partial or total restrictor  23  may be placed between the outer tubular of conveyance device  22  and casing  16  to confine or encourage fluid flow through conveyance device  22 . The inner tubular of conveyance device  22  can comprise various structures including blank pipe, screen on perforated pipe, or screen on unperforated pipe. The outer tubular is preferably unperforated pipe. 
   In an alternate embodiment ( FIG. 2 ), conveyance device  22  may be one or more discreet flow tubes  25  placed around a lower tubular  27 . Again, restrictor  23  may be used to increase flow through the discreet flow tubes  25  of conveyance device  22 . 
   Wellbore  10  often has enlarged regions  26  in various locations within wellbore  10 . For example, region  26  may be the result of washout, where the formation has eroded or collapsed. Region  26  may also be intentionally milled to accommodate a window for a lateral bore, or region  26  may occur when the wellbore diameter is reduced at some depth and casing  16  is not landed completely on the bottom or lower end of the larger diameter portion of wellbore  10 . 
   For example, in subsea wells, it is very common to drill a larger diameter upper section  12  and a smaller diameter lower section  14 . Typically, the larger diameter section  12  is drilled, and casing  16  is set in place with concrete before drilling the reduced-diameter lower section  14 . It is very difficult to land casing  16  exactly on the bottom of upper section  12 , and the concrete may not fill in much below casing  16 . Thus, an enlarged region  26  is created. 
   The enlarged region  26  can be a problem when an operator seeks to gravel pack the annulus between screen  24  and wellbore  10 . The gravel tends to settle out in region  26 , stopping the progress of the gravel pack alpha wave. That can cause the portion of lower section  14  below region  26  not to be packed with gravel. 
   In operation, gravel is normally transported through a central passageway of upper tubular  20  until it reaches crossover  21  just below packer  18 . Gravel exits crossover  21  and tends to pile up and form dunes until it reaches a certain height, depending on slurry speed, sand concentration, and other factors. If restrictors  23  are used, the slurry is discouraged or perhaps even restricted from entering region  26 . Instead, the slurry enters and travels through conveyance device  22  until it emerges below region  26 . In this way slurry is conveyed past the troublesome region  26  and a more complete gravel pack is achieved in lower section  14 . Once lower section  14  is packed with gravel, region  26  may also be filled if sufficient gravel slurry is pumped. 
   Though described in specific terms using specific components, the invention is not limited to those components. Other elements may be interchangeably used, perhaps with slight modifications to account for variations. 
   Although only a few example embodiments of the present invention are described in detail above, those skilled in the art will readily appreciate that many modifications are possible in the example embodiments without materially departing from the novel teachings and advantages of this invention. Accordingly, all such modifications are intended to be included within the scope of this invention as defined in the following claims. It is the express intention of the applicant not to invoke 35 U.S.C. §112, paragraph 6 for any limitations of any of the claims herein, except for those in which the claim expressly uses the words ‘means for’ together with an associated function.

Technology Category: 0