Tools – Wrench – screwdriver – or driver therefor – Machine
Reexamination Certificate
2002-05-06
2004-06-22
Smith, James G. (Department: 3723)
Tools
Wrench, screwdriver, or driver therefor
Machine
C081S057350, C081S057360, C081S057160
Reexamination Certificate
active
06752044
ABSTRACT:
TECHNICAL FIELD
The present invention relates generally to making up and breaking out wellbore tubulars and, more particularly, to apparatus and methods for a simplified self-contained power tong for use in a rig floor environment.
BACKGROUND ART
Power tong systems maybe used to spin, makeup, or connect and breakout or disconnect wellbore tubulars that may have a wide range of diameters. Comparison studies between use of traditional separate tongs and spinners as compared with a self-contained power tong system makeup and breakout tool working under similar conditions have shown cost savings that range from one-quarter of a million to more than a million dollars per well, depending on the well conditions.
Separate, manually operated tongs, spinners, and/or chains are significantly slower and less accurate and consistent in making up and breaking out wellbore tubulars than a single tool or unit that does all such functions. Besides increased speeds of making up and breaking out tubular connections, other time saving advantages of a self-contained power tong unit also include factors such as eliminating the need to redress tongs when changing from drill pipe to drill collars and the integration of spinning with makeup and breakout functions. Due to the high daily cost of drilling rigs, comparison studies show that the time/cost savings can be substantial.
The self-contained power tong system also operates more reliably than separate tongs and spinners and may provide a central torque regulator that connects to and controls all components to assure consistent makeup. This feature prevents thread damage caused by over-tightening and automatically prevents errors that could result in under-torqued connections. Obviously, a single error, when making up hundreds of threaded connections in a drill string, can result in huge costs of time and material, and even loss of a well.
The self-contained power tong system also eliminates accident conditions commonly associated with separately moveable independent tongs which apply high torque and which are located by personnel on the floor. As well, independent tongs have attendant separate cables used to pull on each separate tong, and may also use snatch blocks. Thus, the personnel must work between high tension cables that pull on the tongs and accidents can easily occur under such conditions, e.g., if a tong loses its grip and moves rapidly across the rig floor accelerated by the high tension on the cable. Of course, accidents can slow work progress and significantly increase the costs of drilling.
Safety is also improved because the invention provides a single tool to perform all such functions, rather than separate elements, permits the use of central safety features such as, for instance, a lockout to prevent spinner operation if the tongs are not engaged, a safe location for the operator to stand and work, a design whereby the operator's hands and feet are safely away from moving parts, elimination of spinning chains, and a lockout to prevent operation of the lift cylinder when any tong is engaged.
Because of the great utility of prior art self-contained power tong units to makeup and breakout pipes, and the increasingly expanding market for such devices, it has been found highly desirable to make further improvements. It would be highly desirable to simplify the operation of such devices thereby reducing the number of components necessary for operation of the power tong unit. Consequently, there remains a need for an improved self-contained makeup and breakout unit that reduces the complexity and therefore the costs such as manufacturing costs and maintenance thereof. Those skilled in the art have long sought and will appreciate the present invention which addresses these and other problems.
SUMMARY OF THE INVENTION
The present invention was designed to provide more efficient operation to thereby reduce drilling costs, to improve reliability of making and breaking pipe joints, to permit increased automation to reduce required manpower, to improve safety, and to free other rig equipment for other uses.
Therefore, it is an object of the present invention to provide an improved self-contained power tong unit for making and breaking well bore tubulars.
Another object of the present invention is to provide a self-contained power tong with fewer and more reliable components.
An advantage of the present invention is increased reliability of operation.
Another advantage of the present invention is reduced costs.
Yet another advantage is improved reliability, accuracy, and consistency in making up joints.
These and other objectives, features, and advantages of the present invention will become apparent from the drawings, the descriptions given herein, and the appended claims. However, it will be understood that above-listed objectives and/or advantages of the invention are intended only as an aid in quickly understanding aspects of the invention, are not intended to limit the invention in anyway, and therefore do not form a comprehensive or restrictive list of objectives, and/or features, and/or advantages.
Accordingly, the invention comprises, in one embodiment thereof, a power tong system operable for making and breaking joints between wellbore tubulars. The power tong system may comprise one or more elements such as, for instance, a frame, a spinner secured to the frame that is operable for spinning the wellbore tubulars for the making and breaking of the joints, and/or a first member pivotally connected with respect to the frame such that the first member is rotatable with respect to the frame. The first member preferably defines a bore and/or a slot therein for receiving the wellbore tubulars. Other elements may, for instance, comprise a first plurality of gripping members mounted to the first member which are movable inwardly and outwardly for gripping and releasing the wellbore tubulars, and/or a piston/cylinder assembly comprising a piston slidable within a cylinder. The piston/cylinder assembly may be pivotally mounted with respect to the frame and with respect to the first member such that the first member is rotatable with respect to the frame in response to movement of the piston with respect to the cylinder. Additional elements may comprise a second member mounted to the frame also defining a slot therein for receiving the wellbore tubulars and a second plurality of gripping members mounted to the second member. The second plurality of gripping members may also be movable inwardly and outwardly for gripping and releasing the wellbore tubulars.
The power tong system may further comprise a control arm mounted to the first member, the control arm may be moveable between a first position and a second position, the first member may be rotatable for tightening the wellbore joints in the first position, the first member may be rotatable for loosening the wellbore joints in the second position. Other elements may comprise a fastener for selectively securing the control arm in the first position or the second position. In one embodiment, the fastener further comprises a pin, latch, or other fastening means.
The power tong system may further comprise a pivotal connection between the control arm and the first member and/or a pivotal connection between the control arm and the piston/cylinder assembly.
The plurality of gripping members may comprise a guide member whereby the guide member maybe moveable to a selectable position for a size of the wellbore tubulars. The guide member may then be affixed in the selectable position, and remain affixed, during gripping and releasing of the wellbore tubulars. The guide member cooperates with one or more gripping members that are radially moveable inwardly and outwardly for gripping and releasing the wellbore tubulars. The guide member maybe positioned along the bore through the first member for receiving the wellbore tubulars on an opposite side from the slot.
A method for a power tong system for making and breaking joints between wellbore tubulars are provided that may comprise one or more steps
Frank's International, Inc.
Smith James G.
The Matthews Firm
LandOfFree
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