Patent Application
20110303294
In the drilling and completion industry and for example in hydrocarbon exploration and recovery operations, a variety of components and tools are lowered into a borehole for various operations such as production operations, for example. Some downhole tools utilize ball-seat assemblies to act as a valve or actuator. Ball-seat assemblies are used with, for example, hydraulic disconnects, circulating subs and inflatable packers.
Actuation of a ball-seat assembly generally includes releasing a ball or other plug into a fluid conduit and allowing the ball to drop onto the ball seat and restrict fluid flow therein. The impact between the ball and the ball seat can produce pressure waves, which can cause wear and/or damage to components of the assembly.
An apparatus for restricting fluid flow includes: a ball receiving element disposed in a fluid conduit and configured to receive a ball that has been advanced through the fluid conduit and at least partially restrict fluid flow; and at least one feature disposed on at least one of the fluid conduit and the ball seat configured to reflect pressure waves generated by an impact between the ball and the ball seat.
A method of restricting fluid flow includes: releasing a ball into a fluid conduit and receiving the ball in a ball receiving element disposed at the fluid conduit and at least partially restricting fluid flow; and partially reflecting one or more pressure waves resulting from an impact between the ball and the ball seat by at least one feature disposed on at least one of the longitudinal conduit and the ball seat.
The following descriptions should not be considered limiting in any way. With reference to the accompanying drawings, like elements are numbered alike:
The apparatuses, systems and methods described herein provide for the mitigation of pressure waves caused by actuation of a ball-seat assembly. A downhole assembly includes a conduit having a longitudinal component to guide a ball released into the conduit to a receiving element such as a ball seat. The conduit and/or the ball seat includes one or more features configured to reflect pressure waves caused by, for example, the impact between the ball and the seat. The reflected pressure waves destructively interfere with incident pressure waves to reduce the amplitude of the incident pressure waves and reduce damage and/or wear on downhole components such as the ball and the ball seat.
Referring to
The ball seat 16 may be an annular component connected to the conduit 14, or any other device or configuration providing a restriction in the diameter or cross-sectional area of the conduit 14 sufficient to prevent the ball 18 from passing therethrough. In one embodiment, the ball seat 16 is directly disposed on and/or attached to the inner surface of the conduit 14 or is formed from a reduced diameter portion of the conduit 14. In one embodiment, the ball seat is disposed on or is part of a movable component such as a sliding sleeve for use, for example, as an actuator or valve.
Referring to
The features 20 may be any configuration or mechanism configured to provide reflecting surfaces within the conduit 14 and within fluid flowing through the conduit 14. The features 20 may protrude radially inwardly to reflect the pressure waves 22. In one embodiment, the features 20 are built into the inner surface of the conduit 14 or sleeve. For example, the features 20 may be an integral component of the conduit construction.
In one embodiment, the features 20 include periodic or random contours in the inner surface of the conduit 14. For example, the inner surface may be roughened or otherwise have discontinuities at selected portions of the conduit 14. Other examples of features include saw tooths, baffles, wire screens, and/or macro roughness that is disposed on or part of the interior surface of the conduit 14. In one embodiment, the features 20 include one or more moveable and/or articulated reflecting surfaces such as baffles that are mechanically (via a linkage mechanism) or electrically (making use of a relative movement between a magnet and an electrical conductor) actuated upon the ball-seat impact. In one example, the pressure waves 22 generated by the impact can be utilize to trigger the features 20.
The downhole tool 10 is not limited to that described herein. The downhole tool 10 may include any tool, carrier or component that includes a ball seat assembly. The carriers described herein, such as a production string and a screen, are not limited to the specific embodiments disclosed herein. A “carrier” as described herein means any device, device component, combination of devices, media and/or member that may be used to convey, house, support or otherwise facilitate the use of another device, device component, combination of devices, media and/or member. Exemplary non-limiting carriers include borehole strings of the coiled tube type, of the jointed pipe type and any combination or portion thereof. Other carrier examples include casing pipes, wirelines, wireline sondes, slickline sondes, drop shots, downhole subs, bottom-hole assemblies, and drill strings. In addition, the downhole tool 10 is not limited to components configured for downhole use.
In the first stage 41, in one embodiment, the tool 10 is disposed at a downhole location, via for example a borehole string or wireline. In the second stage 42, the ball-seat assembly is actuated by releasing the ball 18 into the conduit 14, for example by dropping the ball 18 into the conduit 14 and/or pumping the ball 18 through the conduit 14. The ball 18 advances through the conduit 14 and impacts the ball seat 16. In the third stage 43, reflecting features 20 at the ball seat 16 and/or the conduit 14 partially reflect pressure waves 22 resulting from the impact. In the example shown in
In one embodiment, the reflective features 20 are actuateable features such as baffles. The features 20 may be actuated as part of the third stage 43 by a mechanism triggered by the ball seat 16. For example, the triggering mechanism may include a magnetic material in the ball 18 or the ball seat 16 that moves upon actuation of the assembly and/or impact, causing an electrical signal in a conductor that can be used to trigger a baffle or other articulated mechanism to move reflective surfaces into the conduit 14.
The systems and methods described herein provide various advantages over existing processing methods and devices. The net reduction in pressure surge on the ball-seat assembly can enable the use of a wider range of construction materials and reduce the complexity of ball-seat design, for example by reducing the need for relatively complex ball seat designs to reduce impact. In addition, the apparatuses can allow for the ball seat to have a larger inner diameter due to the reduced contact stress.
While the invention has been described with reference to exemplary embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications will be appreciated by those skilled in the art to adapt a particular instrument, situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention.
