Patent Application
20110030965
The field of the invention is active flow control devices that can be associated with a well screen such as a sand screen for selective operation of the screen and more particularly where the valve feature is offset from a single screen section so as to be able to control its flow without reducing drift diameter.
In completions that span multiple zones, an array of screens is frequently positioned in each of the zones. The zones are typically isolated with packers and are individually fractured and gravel packed generally in a downhole to uphole direction. In the past a given zone could be long enough to warrant using multiple screen sections. Typically, each of these screen sections had a base pipe under the screen material and a valve, typically a sliding sleeve, associated with each screen section. The annular space between the screen material and the base pipe for each screen section was sealed at opposed ends on a given screen section and the only access into the base pipe for flow of production to the surface was the sliding sleeve valve in each of the sections.
This configuration required multiple sliding sleeve valves that had to be operated and created issues of flow distribution within a given zone. This lead to the concept of connecting the annular spaces between adjacent screens through the use of ported couplings. This in essence made the various stand alone screens function more akin to a single screen. Several U.S. Patents illustrate the jumper path between the annular flow areas between the screen and its respective base pipe and they are 6,405,800 and 7,048,061. U.S. Pat. No. 6,752,207 shows a way to hook together shunt tubes outside of screen sections through couplings. U.S. Pat. Nos. 6,464,006 and 5,865,251 show gravel packing systems that use screens with sliding sleeves that can close them off such as when a wash pipe with a shifting tool is pulled out of the screen assembly. U.S. Pat. No. 7,451,816 uses base pipe openings in screens that can be covered as an aide to gravel deposition in a surrounding annulus.
Despite the various designs that connected annular spaces in screens through jumper lines and couplings between the screen sections, the base pipes continued to hold the sliding sleeves so that there was still as many sliding sleeves to operate as before to fully open a zone. The other lingering issue of the prior designs was that the location of the sliding sleeves inside the base pipe flow bore and directly under the screen assembly that covered the base pipe was that the resulting flow area or drift dimension of the screen section was diminished which limited the size of tools that could get through a given screen as well as created flow constrictions that could limit production or require the use of artificial lift techniques that consume additional power and create other costs for procurement and installation.
Some screen assemblies included passive valves that would respond to changing well conditions to move between open and closed positions. Illustrative of this concept are U.S. Pat. Nos. 7,409,999 and 7,290,606.
Those skilled in the art will appreciate that the present invention provides for effective control of the flow through a screen section without reducing the drift diameter. One way this is accomplished is to axially offset the location of the valve that is preferably a sliding sleeve in a recess that is not aligned with the screen and the base pipe that passes below the screen. In that manner greater advantage can be taken of the ability to modify the wall thickness in a region offset from the screen assembly so that the placement of the sliding sleeve can be such that the drift diameter through the overall screen assembly is not reduced. These and other advantages of the present invention will be more apparent to those skilled in the art from a review of the description of the preferred embodiment and the associated drawing while recognizing that the full scope of the invention is to be determined by the appended claims.
A screen assembly for downhole uses features screen sections that have a valve associated with the screen base pipe. Flow through the screen has to go into an annular space to reach one or more ports on the base pipe over which is located a sliding sleeve. The sliding sleeve is preferably located at an axially spaced location from the screen and its underlying base pipe to allow the presence of the sliding sleeve to be located in a recess avoiding a drift diameter reduction in the screen assembly.
A screen assembly 10 is welded at 12 to a base pipe 14. Threads at a lower end 16 can be used to connect another screen section (not shown). It should be noted that there are no openings in the base pipe 14 under the screen assemblylo directly into the flow path 18 that runs to the surface. Instead there is an annular space 20 that is in part defined by the screen assembly 10 and the base pipe 14 and is further defined by an outer housing 22 that is mounted over a flow control device 24 that can be a tortuous path or some other flow control technique for equalizing flow among different screen assemblies with only one being shown in
Thread 28 can be used to secure the base pipe 14 to the sliding sleeve housing 26 or alternatively those components can be welded together. A flow passage 30 extends from annular space 20 to an end 32 near the sliding sleeve 34. Sliding sleeve 34 has a passage 36 to provide flow access in the
Profiles 38 and 40 are located near opposed ends of the sleeve 34 so that a shifting tool (not shown) but known in the art can grab the sleeve 34 an use each of the profiles to move sleeve 34 in opposed directions. It should be noted that sleeve 34 can be either translated or rotated to align or misalign end passage or passages 32 with passage or passages 36. The operation of the sleeve 34 can be surface controlled in a variety of ways including a localized motor or control lines leading to an operating piston to name a few examples.
The sliding sleeve housing 26 has a pair of opposed travel stops 42 and 44 that are radial shoulders that define a recess 46 that is deeper than the thickness of the sliding sleeve 34 so that the presence of sleeve 34 in recess 46 does not decrease the drift dimension of the passage 18 that leads to the surface. It is the placement of the sliding sleeve 34 in an axially offset location from the screen assembly 10 that allows the placement of the sleeve 34 in a manner where the drift diameter of passage 18 is not reduced. The housing 26 can simply be made thicker to retain its pressure rating on its outer dimension and still not extend radially outwardly beyond the adjacent screen assembly 10.
Connection 48 is for attaching more screens and eventually a packer and a string that extends to the surface. The inflow control device 24 is optional and can be omitted. The housing 26 can be integral to the base pipe 14 in a single joint of pipe or it can be a separate structure joined to the base pipe that comprises a stock length of tubular. In the latter case the housing 26 can be a separate coupling attached to the base pipe 14 in a variety of ways but preferably threading.
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:
