Method and apparatus for catching darts and other dropped objects
a technology of throwing objects and methods, applied in the direction of drilling casings, drilling pipes, borehole/well accessories, etc., to achieve the effect of not breaking or bending during us
Inactive Publication Date: 2015-10-29
BLACKHAWK SPECIALTY TOOLS
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- Description
- Claims
- Application Information
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Benefits of technology
[0020]In the preferred embodiment of the present invention, the collet fingers of the present invention are cut at an angle—that is, not radially outward from the central bore of the collet seat. As the collet fingers of the present invention spread or expand outward, said fingers push against each other but do not create gaps that can catch or tear dart fins.
[0021]As with other embodiments of the present invention, this embodiment of the present invention comprises a downhole dart catcher receptacle to catch drill pipe wiper darts. When such a dart is seated within said collet seat of the dart catcher receptacle, flow is restricted through said dart catcher receptacle. As a result, fluid (primarily pump) pressure from above creates a pressure differential across the seated dart, resulting in a pump pressure increase observable at the surface when each dart lands in the tool. The modular design of the collet and mating darts allows multiple darts to be utilized with a single tool.
[0022]Collet fingers of the present invention can beneficially flex, but always overlap one another to prevent any gaps between said fingers. The darts of the present invention have body sections small enough to fit through the expanded collet seat, yet strong enough not to break or bend during use. Dart passage pressure through said collet seat can be modified by adding / removing c-rings to the outer diameter of the collet seat, or by machining the collet fingers to have desired material characteristics.
[0024]In all embodiments, the dart catcher receptacle of the present invention provides sufficient clearance to allow a minimum equivalent flow diameter substantially the same as drill pipe (i.e., no flow restriction) and allow both forward and reverse flow through said tool. A catcher tube has enough bypass ports to allow minimum equivalent flow diameter as drill pipe (i.e., no flow restrictions) per foot and allow both forward and reverse flow through the tool. Flow slots are positioned such that reverse flow is possible even if a dart is pushed back up and covers the inlet to said catcher tube.
Problems solved by technology
However, it is to be understood that such terminology is not intended to be, nor should it be construed as, limiting in any manner.
Method used
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[0038]FIG. 1 depicts a perspective view of a first embodiment of a wiper dart 100 equipped with the shearable sleeve 110 of the present invention. As depicted in FIG. 1, wiper dart 100 embodies a typical configuration of a conventional wiper dart, in that it comprises substantially cylindrical central stem member 101, as well as fin members 102 that extend radially outward from said central stem member 101. Said fin members 102 are flexible and can beneficially partially collapse or fold; in certain applications, said fin members 102 can be used to contact and wipe internal pipe surfaces, while being capable of passing through restrictions that may be encountered in such pipe.
[0039]Still referring to FIG. 1, wiper dart 100 comprises dart nose 104. Although the specific design of said nose 104 can vary, in the dart embodiment depicted in FIG. 1, said nose 104 includes tapered surface 103. Shearable sleeve 110 having tapered shoulder surface 111 is disposed on said nose 104. Said shea...
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A dart or other dropped object having a rigid nose is dropped or launched down hole, typically during cementing operations, until it lands on a resilient seat within a dart catcher receptacle. By increasing a pressure differential across the landed dart to a predetermined amount, the dart extrudes through the seat and passes into a ported catcher sub. The seat member can be constructed of engineered composite material that does not yield in response to passage of the dart and returns to its original size following such passage.
Description
CROSS REFERENCES TO RELATED APPLICATIONS[0001]This application is a continuation of U.S. patent application Ser. No. 13 / 665,422, filed Oct. 31, 2012, currently pending, which claims priority of U.S. Provisional Patent Application Ser. No. 61 / 554,255, filed Nov. 1, 2011, all incorporated herein by reference.STATEMENTS AS TO THE RIGHTS TO THE INVENTION MADE UNDER FEDERALLY SPONSORED RESEARCH AND DEVELOPMENT[0002]NoneBACKGROUND OF THE INVENTION[0003]1. Field of the Invention[0004]The present invention pertains to a method and apparatus for performing cementing operations in oil and / or gas wells. More particularly, the present invention pertains to a method and apparatus for catching darts or other objects dropped or launched during such well cementing operations.[0005]2. Brief Description of the Prior Art[0006]Conventional rotary drilling rigs typically comprise a supportive rig floor, a substantially vertical derrick extending above said rig floor, and a traveling block, top drive uni...
Claims
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IPC IPC(8): E21B33/12
CPCE21B33/12E21B33/16
InventorJORDAN, J. CHRISTOPHERGROESBECK, BRAD
OwnerBLACKHAWK SPECIALTY TOOLS