1. Field of the Invention
Embodiments of the present invention generally relate to packer cups for use in a wellbore.
2. Description of the Related Art
The following descriptions and examples are not admitted to be prior art by virtue of their inclusion within this section.
Packer cups are often used to straddle a perforated zone in a wellbore and divert treating fluid into the formation behind the casing. Packer cups are commonly used because they are simple to install and do not require complex mechanisms or moving parts to position them in the wellbore. Packer cups seal the casing since they are constructed to provide a larger diameter than the casing into which they are placed, thereby providing a slight nominal radial interference with the well bore casing. This interference, “swabbing,” or “squeeze,” creates a seal to isolate a geologic zone of interest and thereby diverts the treating fluid introduced into the casing into the formation.
Packer cups were developed originally to swab wells to start a well production. In recent years, packer cups have been used in fracturing or treatment operations carried out on coiled tubing or drill pipe. Such operations require higher pressures and may require multiple sets of packers or isolations across various individual zones. The demand on the sealing performance of the packer or isolation elements is high and their integrity is critical. Thus, packer cups that are capable of withstanding the high differential pressures encountered during fracturing or treatment operations are desired. Furthermore, a cup configuration that is capable of traversing equipment or irregularities in the borehole, such as casing collars, perforation burrs, minor restrictions or wellbore damage or any other type of wellbore obstruction, with minimal cup damage is also desired.
It is with respect to the above referenced considerations and others that embodiments of the invention have been made.
Various embodiments of the invention are generally directed to a packer cup for use inside a wellbore. In one embodiment, the packer cup includes a body, a support member disposed inside the body, and one or more support layers disposed against an inside diameter of the support member.
In another embodiment, the packer cup includes a body and a support member disposed inside the body. The support member includes a plurality of curved wires.
In another embodiment, the packer cup includes a body and a support member disposed inside the body. The support member includes a plurality of slats.
In yet another embodiment, the packer cup includes a body and a support member disposed inside the body. The support member is made of a composite material.
In still another embodiment, the packer cup includes a body and one or more support layers disposed inside the body. The support layers are made from a fabric material.
Other embodiments of the invention are directed to a method for straddling a perforated zone in a wellbore. The method includes attaching a packer cup to a straddling tool. The packer cup includes a body, a support member disposed inside the body, and one or more support layers disposed against an inside diameter of the support member. The method further includes deploying the straddling tool to a desired location and increasing fluid pressure inside the packer cup to squeeze the fluid into a wellbore formation, thereby isolating the perforated zone.
The claimed subject matter is not limited to implementations that solve any or all of the noted disadvantages. Further, the summary section is provided to introduce a selection of concepts in a simplified form that are further described below in the detailed description section. The summary section is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter.
So that the manner in which the above recited features of the present invention can be understood in detail, a more particular description of the invention, briefly summarized above, may be had by reference to embodiments, some of which are illustrated in the appended drawings. It is to be noted, however, that the appended drawings illustrate only typical embodiments of this invention and are therefore not to be considered limiting of its scope, for the invention may admit to other equally effective embodiments.
Once the straddle tool 10 is in position adjacent the selected formation zone 18, the straddle tool 10 may be operated from the earth's surface to deploy anchor slips 24 to lock itself firmly into the casing 20 in preparation for fracturing or treating the selected formation zone 18. The straddle tool 10 may include one or more packer cups 26. When pressurized fracturing or treating fluid is pumped from the earth's surface through the string of coiled or jointed tubing 16 to the straddle tool 10, the pressure of fluid exiting the straddle tool 10 may force the packer cups 26 to engage the casing 20 proximate one or more treating ports 28. The open ends 29 of the cup packers 26 may be arranged to face each other and straddle an interval 30 of the wellbore 12 between the packer cups 26.
When the packer cups 26 have fully engaged the casing 20, the formation zone 18 and the straddled interval 30 between the packer cups 26 will be pressurized by the incoming fracturing or treating fluid. Upon completion of fracturing or treating of the formation zone 18, the pumping of fracturing or treating fluid from the earth's surface may be discontinued, and the straddle tool 10 may be operated to dump any excess fluid, thereby relieving the pressure in the straddled interval 30.
Packer cups are generally configured to seal against extreme differential pressure. Packer cups should also be flexible in order to run into a well without becoming stuck and durable so that high differential pressure can be held without extrusion or rupture. As such, packer cups have historically been constructed from strong and tear resistant rubber materials. Examples of materials that have been used in the past include nitrile, VITON, hydrogenated nitrile, natural rubber, AFLAS, and urethane (or polyurethane). A typical elastomer is less flexible when steps are taken to improve its tensile strength. For example, a more cross-linked nitrile rubber may have higher durometer hardness and tensile strength, but it is more likely to experience high friction forces and be damaged when the rubber must flex around an obstruction in a well bore. A material that possesses the flexibility of a soft nitrile rubber but has the tear strength and tensile strength of a much harder rubber would both improve the ease with which the cup may be transported into a well bore and also improve the capability of the cup to withstand high differential pressure.
In another embodiment, the support layers 430 may be disposed outside the support member 420, as shown in
While the foregoing is directed to embodiments of the present invention, other and further embodiments of the invention may be devised without departing from the basic scope thereof, and the scope thereof is determined by the claims that follow. Although the subject matter has been described in language specific to structural features and/or methodological acts, it is to be understood that the subject matter defined in the appended claims is not necessarily limited to the specific features or acts described above. Rather, the specific features and acts described above are disclosed as example forms of implementing the claims.
This application is a continuation-in-part of co-pending U.S. patent application Ser. No. 11/093390 entitled Carcass for Open Hole Inflatable Packers, filed Mar. 30, 2005, which is herein incorporated by reference.
Number | Date | Country | |
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Parent | 11093390 | Mar 2005 | US |
Child | 11291010 | Nov 2005 | US |