Patent Publication Number: US-7721810-B2

Title: Large inside diameter completion with position indication

Description:
FIELD OF THE INVENTION 
   The field of this invention relates to downhole completion assemblies and more particularly to those that place the position locaters for through packer assemblies above the packer to reduce restriction presented by position locators traditionally placed below a completion packer. 
   BACKGROUND OF THE INVENTION 
   Gravel pack systems allow many downhole procedures to take place in a single trip. A gravel pack assembly typically contains sections of screen that extend from a packer. An inner string that includes a crossover tool is movable with respect to the set packer for selective sealing relation with a polished bore in the packer. In this manner fluids can be circulated when the assembly is run in and gravel can be deposited outside the screens while return fluids can come up through the screens and up a wash pipe. These return fluids can then pass through a valve in an uphole direction and go through the crossover and back to the surface through the annulus above the set packer. Alternatively, the crossover can allow the gravel to be deposited with fluid squeezed into the formation in a procedure called a frac pack. The crossover is simply positioned with respect to the packers and seal bores in a manner where no return port through the wash pipe and back to the surface is open. 
   Regardless of whether the gravel is deposited with fluid returns to the surface or whether the fluid is forced into the formation when the gravel is deposited outside the screens, the excess gravel in the string leading down to the crossover has to be removed, typically by a process called reversing out. In this step the crossover is repositioned so that fluid pumped from the surface in the annular space above the packer is allowed into the tubing above the packer so that the excess gravel can be brought to the surface. It is the locating of these positions downhole that is vital to the correct operation of the tool. Performing this procedure can build pressure near the crossover and a risk of fluid loss to the formation with this built up pressure is a possibility. Fluid loss to the formation can diminish its productivity and excessive fluid loss to the formation may inhibit or prevent reverse circulating of the excess gravel from the workstring. For these reasons a fluid loss control valve in the wash pipe extending into a packer seal bore from the crossover has been used. These fluid loss control valves are illustrated in patents relating to gravel packing operations such as U.S. Pat. Nos. 7,290,610; 7,128,151; 7,032,666 and 6,983,795. 
   As an introduction to an understanding of the preferred embodiment, a brief discussion of the prior designs and the issues it presented will be undertaken in a summary form.  FIG. 1  shows a common prior art assembly for gravel packing. A wellbore  20  has a string  22  with a packer  24  shown in a set position. A crossover tool  26  with a wash pipe  28  extends through a screen assembly  30  that is properly located by a formation  31  using a tubular spacer  29 . The screen assembly  30  has profiles  32  on which a collet  34  that is connected to the wash pipe  28  can be landed to provide the desired flow configurations for the gravel packing operation. In order to direct fluid flow it is necessary that the packer  24  sealing bore  38 ′ be compatible with the crossover tool  26 , such that the crossover tool seals in the seal bore. In the  FIG. 1  position a fluid loss control valve  36  is locked in the open position. The  FIG. 1  position allows circulation with flow coming down the string  22  and going through the crossover tool  26  to emerge outside the screen assembly  30 . Flow then goes through the screen assembly  30  and into the wash pipe  28  and through the flow control valve  36  and back through the crossover tool  26  to the annulus above packer  24  and around the string  22  to the surface. 
   Note that in  FIG. 1  the collet  34  is set down on one of the profiles  32  to define a circulating position. In  FIG. 2  the collet  34  is back to the same position as in  FIG. 1  to define a position for delivering gravel  27  either by circulation or by what&#39;s called a frac pack where the returns in the annulus  44  above the packer  24  are shut off at the surface. After that, further string manipulation in  FIGS. 3 and 4  allows the collet  34  to indicate in different locations and directions on profiles  32  so as to place the internal assembly in position to evacuate excess gravel from the crossover tool  26  in  FIG. 3  and from the string above the packer  24  in  FIG. 4 . 
   With this prior art configuration and the crossover tool  26  sealing in the packer  24  sealing bore  38 ′ it was necessary to have the profiles  32  smaller than the packer  24  sealing bore  38 ′. As a result when the well is put on production, the profiles present resistance to production flow through the screen assembly  30 . 
   The present invention is directed at finding an alternative location for these profiles and the preferred location is in a region above the packer where the profiles can be larger since the annulus above the packer need not be as large as below it since only screened returns pass through that annulus. These and other aspects of the present invention will become more apparent from a review of the description of the preferred embodiment and the associated drawing while recognizing that the appended claims define the literal and equivalent scope of the invention. 
   SUMMARY OF THE INVENTION 
   A completion assembly has a packer for zone isolation and indicating shoulders incorporated into a sleeve mounted uphole of the packer. Locating the indicating shoulders above the packer allows them to be larger than placement below the packer where the assembly generally has to neck down to create sealing points and a sufficiently large annular space to permit operations such as gravel packing. Placement above the packer makes the indicating shoulders less restrictive to subsequent production flow or for passage of tools further down the wellbore. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a section view of a gravel packing assembly known in the art in a circulating position; 
       FIG. 2  is the view of  FIG. 1  with the assembly in a frac pack mode; 
       FIG. 3  is the view of  FIG. 2  with the assembly in position to reverse out excess gravel from the crossover tool; 
       FIG. 4  is the view of  FIG. 3  with the assembly in position to reverse out excess gravel from the string above the crossover; 
       FIG. 5  is a section view of the present invention showing the indicating shoulders above the packer. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     FIG. 5  shows the packer of  FIGS. 1-4  and now labeled  24 ′ as a quick way to understand the difference from the prior technique, described above in a gravel packing context, and the present invention applied to the same technique to illustrate one application of the present invention. The collet  34 ′ is the same but it is now positioned above the packer  24 ′ and still on string  22 ′ which continues to the surface (not shown). A setting tool  100  is part of the string  22 ′ and incorporates a sleeve  102  with preferably integrated landing shoulder assemblies  104 ,  106  and  108 . The collet  34 ′ can land on an upper surface such as  110  or a lower surface  112  on any of the landing shoulder assemblies. The crossover tool  26 ′ is shown adjacent the packer  24 ′. In the  FIG. 5  position, the crossover tool  26 ′ is landed on the packer  24 ′. While such a position defined in the previous sentence could be accomplished in the design of  FIGS. 1-4 , there are multiple positions required to execute a procedure such as a frac pack or gravel pack and a single landing position of the crossover tool  26 ′ on the packer  24 ′ is not sufficient. Screen  30 ′ is mounted below packer  24 ′ with no indicating shoulders located between the packer  24 ′ and screen  30 ′. 
   Optionally, flow control valve having a sleeve  200  to selectively cover a port  202  such as an RB valve offered by Baker Oil Tools can be placed in the sleeve  102  to control fluid flow into the formation. Setting sleeve  102  can set the packer by relative movement with respect to string  22 ′ in a known manner. After performing the needed downhole operation the string  22 ′ can be pulled taking with it the setting tool  100 . A production string (not shown) can then be tagged into packer  24 ′. The profiles  32  shown in the prior design in  FIGS. 1-4  are now larger than they were in the traditional gravel packing operation. For that reason they do not restrict the passage below the packer  24 ′ as they used to do. 
   As an example the sleeve  102  can have an outside diameter of 8.125 inches while the peak  118  can have an inside diameter of 6.625 inches, which is larger than the seal bore  38 ′ in the packer  24 ′. In the prior art location below the packer the peaks of the indicating shoulders  32  would be smaller than the packer seal bore  38  forcing a smaller string to be set in a sealing relationship with the packer  24  than in the present invention shown in  FIG. 5  where the full seal bore diameter in the packer can be used without restriction from shoulder assemblies  104 ,  106  and  108  after the string  22 ′ is pulled and a production string (not shown) is inserted.