Patent Application
20090188676
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.
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.
Note that in
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.
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.
Optionally, flow control valve 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
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
