Patent Application
20150337628
The field of the invention is mechanically actuated valves that are used to balance flow or isolate flow among producing or injection zones and more particularly where the valves can be adjusted into multiple open positions and a closed position.
In the drilling and completion industries it is often desirable to affect tools or formations at a great distance from a surface located facility such as a rig, production facility, or wellhead. One example of an operation intended to affect a formation production is manipulation of a downhole choke to adjust flow rates from or into various zones or reservoirs segments. In order to perform such an operation, a choking mechanism can be actuated either hydraulically, electrically or the combination of these means. In the art, using these types of control generally require a number of control lines run from the surface through the wellhead related to changing the choke sizes at discrete locations in the wellbore. Such tools increase expense initially and generally create other issues to be overcome during well construction and completion operations. Where multiple choking locations are contemplated, generally control lines must pass through packers and other wellbore devices to allow a choking system be installed and administered correctly for it to work. Since choke adjustment happens infrequently the system of control lines is rarely used and only complicates well construction and completion operations.
Instead a far simpler system is contemplated where each valve has a unique profile for engagement by a shifting tool so that axial movement of the shifting tool will actuate a j-slot to rotate a pin extending from a sleeve that is in registry with a shaft having a reversing screw profile. Operation of the j-slot moves the pin in the track of the profiled shaft. The profiled shaft is constrained against rotation but is free to move axially in opposed direction. The choke valve member is tied to the translating profile shaft to allow the choke to move between fully open and fully closed and into positions in between. The profile shaft reverses direction at the fully open and fully closed positions of the choke to accomplish the closed, full open and part open positions that are in between.
Reversing screws are known and described in U.S. Pat. No. 4,998,576 in the context of a window mechanism. Typically the profile shaft is fixed against lateral movement and its rotation on its own axis drives a follower in opposed directions. The operation in the present invention is reversed in that a j-slot drives the follower along the profile on the profile shaft that is restrained against rotation so that rotational movement of what has traditionally been the follower in effect causes the profile shaft to move axially in opposed directions within a predetermined travel range.
A series of chokes accessible to a tool that engages unique profiles make it possible to balance flows from or into zones or to completely close off zones as desired. The system is economical as compared to systems that require control lines or power to drive motors at various locations. Other aspects of the present invention will be more readily apparent to those skilled in the art from a review of the description of the preferred embodiment and the associated drawings while recognizing that the full scope of the invention is to be determined from the appended claims.
A series of independently operated chokes, using a shifting tool in registry with a profile unique to each choke, have a tubular valve member that aligns or misaligns openings for the fully open or closed positions for the choke and for intermediate positions as the valve opens or closes. The valve member is actuated axially using a reversing screw and a j-slot. A shifting tool latches a unique profile to operate the j-slot to cause a sleeve to rotate in place. The sleeve has a pin in registry with a profile on a profile shaft. The profile shaft can move axially in opposite direction but is restrained against rotation. The profile is shaped so that continuous j-slot operation causes the registered pin to move in the profile to then axially drive the profile shaft which is connected to the valve member.
Axial manipulation of profile 20 and the presence of the j-slot pattern 26 causes pin 24 to rotate. Pin 24 sits in the self-reversing profile 28 of shaft 30 that is enabled to move axially in the directions of arrow 22. However shaft 30 is keyed to prevent rotation by a key that is not shown but that engages in elongated slot 32. Thus in order for the pin 24 to progress in helical reversing profile 28, the shaft 30 has to translate in the directions of arrow 22. Axial movement of shaft 30 causes a similar tandem movement in valve member 16. There is a return bias 34 that can be a spring or pressurized compressible gas that provides a force in the direction of arrow 36. The j-slot assembly 28 defines angular movement increments of pin 24 along the profile 28, which, in turn, defines a predetermined axial movement of shaft 30 and valve member 16 either toward alignment or misalignment of opening 18 with opening 14.
Each such tool 10 can be operated with the shifting tool T when a different profile is fitted. In such a manner the flows from the formation in production or into the formation when injecting can be balanced to get the desired result of controlling water or sand production, for example. Particular zones can be closed entirely. The shifting tool can carry multiple profiles with a facility to expose different profiles for engagement with mechanical or hydraulic inputs such as to shift cover sleeves away from designated profiles so that more than one tool 10 can be shifted in a single trip into the borehole. The tools 10 are independently mechanically operated taking away the need for control lines or power cables to actuating motors that increase expense encountered by the prior designs that used hydraulic or electric motor drivers.
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:
