Patent Application
20130206394
The field of this invention is screen assemblies for subterranean use made from a plurality of sections that are threaded together. Shunt tubes extend exterior to the screens to a coupling assembly that uses an internal mandrel spanning the coupling connection for internally manifolding the shunts in an annular path. At least one of the shunts on any joint can have sloping outlets with adjacent standoffs.
Screen assemblies are frequently used in completions in association with gravel packed around the screen sections in the annular space that surrounds the screens. Getting a good distribution of gravel is important for the effectiveness of the gravel pack as an aide in trapping particulates in the produced fluids and thus extending the service life of the screens. Getting the gravel to distribute evenly particularly in horizontal completions has always been an issue. Another issue is the tendency of the gravel to bridge so that gaps over the screens are formed where there is no packed gravel. Apart from the operational issues there are issues with ease of assembly of the joints of screen and connecting the shunts that go through the screens or outside of the screens.
On design that connects the annular spaces between screen and base pipe of adjacent screen sections is shown in U.S. Pat. No. 6,405,800 where a passage from the adjacent annular spaces under adjacent screens goes through an annular passage in a coupling using an internal mandrel that spans the joint with openings at opposed ends to connect the adjacent annular spaces between adjacent screens. Other examples of flow through connectors used with screens are U.S. Pat. Nos. 7,048,061; 6,170, 522; 6,192,924; 6,196,596; 4,508,135; 7,147,003; 6,409,219; 5,082,052; 6,752,207; 5,868,200; 5,476,143; 4,510,996; 6,923,262 and US Publication 2009/0095471.
These designs had various limitations in the areas of ease of assembly, durability or in the limited configurations they made possible. They connected shunts individually across a joint; they had a clamshell design that had to be bolted across a joint; they provided a limited number of shunt orientations before the pattern repeated or they simply connected annular spaces under adjacent screen sections. The present invention addresses these issues in a way that those skilled in the art will appreciate that allows rapid manifolding of shunts across a threaded connection as well as multiple patterns of a shunt with gravel outlets in combination with shunts that have no outlets so as to orient the gravel outlet shunt on a given joint in multiple circumferential orientations without using complex structures such as timed threads or floating shunt tube assemblies, which are free to rotate during make up on the rig floor. These and other aspects of the present invention will be more readily apparent to those skilled in the art from a review of the discussion of the preferred embodiment and the associated drawings while appreciating that the full scope of the invention is to be found in the appended claims.
An assembly of screens made of connected joints with exterior shunts that span the threaded connections among the joints features manifolds for the shunts adjacent joint threaded ends that are connected with a coupling. A mandrel spans from one joint to the next inside the threaded coupling and is sealed to the respective bases pipes on opposed ends of the coupling. At each end of the mandrel the surrounding base pipe has openings from the manifold where the shunts terminate to define an annular flow path between pairs of manifolds. The shunts can have slanted gravel outlet passages or no gravel openings at all. The shunts can span over screen or blank pipe with an option to mount a shroud over the generally parallel shunts.
Referring to
Off to the left end of
Referring to FIGS. 2 and 4-6 it will be seen that the preferred arrangement on any joint with a screen is to have a single shunt such as 44 that has outlet ports 48 and 50 and a lower open end 52. The outlets 48 and 50 have openings with an outlet sloping face 54 to minimize the erosion effects of gravel that flows through. There are opposed parallel standoffs 56 and 58 to promote gravel exit flow by raising the opening from the surrounding wellbore wall.
What is illustrated is a system that is assembled quickly that can connect shunts across a coupling through a passage that is annular and extends within the coupling so that the shunts are manifolded together on opposed ends of the threaded connection. An inserted mandrel with end seals against base pipes on opposed ends of the coupling and ports on the base pipes on opposed sides of the coupling define each annular flow path. Shunts without openings can be used to connect the spaced apart manifolds and the shunts can also be used to span sections of blank pipe. While the shunts are preferably outside the screen sections where the screen is sealed on opposed ends to the outside of the blank pipe, other arrangements are contemplated such as running some or all the shunts under the screen and cutting out parts of the screen for gravel outlets from the shunts. Alternatively some shunts can be over the screen with exit ports while others can be under the screen. While the shunts are shown as extending generally axially they can also be spirally oriented on the base pipes.
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:
