BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a section view of the tool with a seated first ball and the circulation port closed;
FIG. 2 is the view of FIG. 1 with the first ball released, the port open and the second seat now supported to accept a second ball as big as the first;
FIG. 3 is the view of FIG. 2 with the second ball landed on the second seat; and
FIG. 4 is the view of FIG. 3 with the second seat shifted, releasing the second ball and the port closed.
DEATAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
FIG. 1 illustrates the position of one module of the present invention after run in and the dropping of a ball 10 to land on a seat 12. Seat 10 is formed of a series of abutting collet heads 14 that are supported in bore 16. The collet heads 14 are mounted to a series of collet fingers 18 that extend from piston 20. Piston 20 comprises a ring 22 with a solid sleeve 24 extending down from it. In the run in position, a flow port 26 is covered by sleeve 24 and is closed because seals 28 and 30 straddle port 26. An upper segment 32 is connected to ring 22 for tandem movement. It has a larger internal diameter 34 that is initially opposed to collet heads 36 in a manner that preferably gives them no support so that ball 10 can readily pass through collet heads 36 in the FIG. 1 configuration without getting hung up. Upper segment 32 has a reduced diameter 38 shown in FIG. 2 that can come into position behind the collet heads 36 to give them full support, as will be described later.
Sleeve 24 is initially secured to the housing 40 by a shear pin 42 or by equivalent devices. The presence of pin 42 allows pressure to build on seated ball 10 in the FIG. 1 position to operate some downhole tool (not shown) such as a packer or liner hanger, for example. If pressure on ball 10 exceeds a predetermined value, which happens after some other tool is actuated, then the shear pin 42 breaks and the ring 22 moves down taking with it sleeves 24 and 32, as shown in the FIG. 2 position. This movement puts collet heads 14 in recess 44 letting loose the grip on ball 10. Sleeve 32 has a series of elongated openings 46 that now straddle port 26 while seals 28 and 30 on sleeve 24 are well below port 26. Reduced diameter 38 is defined by sleeve segments that surround the elongated openings 46 to allow in FIG. 2 the sleeve 32 to now provide support for collet heads 36. Those skilled in the art will appreciate that collet heads 36 allowed ball 10 to pass in the FIG. 1 position are, in the FIG. 2 position able to catch another ball 48, shown in FIG. 3, that is the same size or smaller than ball 10. Thus far, in FIGS. 1 and 2, a downhole tool has been operated and the circulation valve has been opened while the ball 10 has been released from collet heads 14. The shifting of the assembly 20 has also now provided support to collet heads 36 so that they can receive a ball of a size they formerly let pass.
FIG. 3 shows a ball 48 landed on collet heads 36 so that pressure can now be built up on ball 48 to break shear pin or equivalent 50, after actuating some downhole tool, so that piston 52 with seals 54 and 56 can slide down to the FIG. 4 position until it butts up against ring 22, which at this point is stationary. FIG. 4 shows the seals 54 and 56 straddling port 26 so as to close it off because piston 52 is a solid sleeve. Furthermore, collet heads 36 have been moved down with piston 52 due to pressure on ball 48 so that they are now in alignment with larger diameter surface 34 once again as they were in FIG. 1. Now the ball 48 can pass by collet heads 36 as well as collet heads 14 now unsupported because of their alignment with groove 44.
The motions that a single modular housing 40 can undergo have been illustrated in the context of a circulation valve. A bottom hole assembly can employ multiple modules that work identically as circulation valves but are deployed at different depths. Alternatively, a single module can also comprise sufficient components to open and close a circulation port more than once. In yet another variation the module can accomplish other downhole operations rather than opening or closing a valve. The pressure operation made possible by the device can also simply allow other tools to be operated with a series of objects that do not need to be successively larger as has been the case in the prior art. Indeed, the modular housing 40 does not need to have a port such as 26 if it is not being used as a circulation valve.
There are many unique features of the present invention that should be mentioned. One is that successive objects, preferably spheres, can be used in succession where subsequent objects are no larger than the previously inserted objects. The release of one inserted object sets up the receipt of another no larger object on a different seat. That seat can subsequently release the later inserted object. The multiple seats allow operations of various tools and no significant drift restriction after the inserted objects are passed by the device. Apart from letting other downhole tools be operated in a desired sequence, the shifting or loss of support for the seats can also be deployed to operate a circulation valve or yet other tools whose operation can be wholly independent of the pressurization function on the seated balls.
Yet another optional feature of the present invention is that collet fingers 18 down to heads 14 can be lined with a material that stretches and is compatible with downhole conditions. This material can be in the form of a sleeve 60 that is secured to the inside of the collet fingers to effectively block the spaces between fingers 18 thus acting as a debris barrier. It can be preferably made of rubber but other materials compatible with downhole conditions can be used. It can be a solid sleeve or a coating on the inside surfaces of the collet fingers or any condition in between. The material 60 can go down to the collet heads 14 so that when the ball 10 arrives, it seals against the material as opposed to a line contact on the sphere 10 with the associated collet heads 14. Similarly, the same treatment can be applied using the material 64 on collet fingers 62 and on down to the associated collet heads 36. The function and operation is the same as described above.
The above description is illustrative of the preferred embodiment and many modifications may be made by those skilled in the art without departing from the invention whose scope is to be determined from the literal and equivalent scope of the claims below.
Patent Application
20080093080
