Patent Application
20080311776
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The present invention relates to well completions including signal or control lines and more particularly to a self orienting connector system for connecting an upper portion of a signal or control line to a lower portion thereof while installing a well completion.
Wells are drilled into the Earth to explore for and produce hydrocarbons and other fluids. If hydrocarbons are to be produced, the well must be completed. Completing a well typically includes setting and cementing casing in at least an upper portion of a well and installing other equipment to facilitate, control and monitor production of fluids. Such equipment may include a gravel packing assembly to restrict the production of sand with the desirable fluids. Temperature and pressure sensors are commonly installed to monitor conditions, especially in the lower completion, i.e. in and near productive zones. Valves, and actuators to control the valves, may be installed to control the flow of fluids. Signal and control lines are desirably provided from the downhole equipment to the surface location of the well to allow sensor outputs to be read and recorded and to allow control signals to be sent to the downhole equipment.
A lower completion typically includes equipment extending from the cased and cemented portion of the well down to and through producing formations. The basic structural component of a lower completion is a tubing or flow line through which fluids produced from the Earth are flowed up the well. The upper end of a lower completion typically includes a packer that provides an annular seal between the upper end of the flow line and the inner surface of the casing. The lower completion is installed before the upper completion, and may be installed weeks or months before the upper completion is installed, especially in the case of a sub-sea well. The lower completion normally contains signal and control lines needed for the sensors, valves, etc. included in the lower completion.
An upper completion includes a flow line that extends from the surface location of the well down to the packer where it is connected to the upper end of the lower completion to form a continuous flow path from the productive zone to the surface of the Earth. The upper completion may also include signal and control lines that extend from the surface of the Earth down to the packer for connection to the upper ends of the signal and control lines that were installed as part of the lower completion.
In prior art completions, signal and control lines forming part of a lower completion are terminated above the packer. Upon installation of the upper completion, the connections to the portion of the signal and control lines forming part of the upper completion are made above the packer. This prior art arrangement requires that a separate conduit or interior flow path be provided through the packer, normally through the packer mandrel, for the signal and control line or lines. The primary conduit or interior flow path through a packer is used for the production tubing and is desirably as large as possible. If one or more additional interior flow paths is required for signal or control lines, the size of the primary flow path must be reduced.
A well completion system includes a lower completion comprising a packer, a first length of production tubing having an upper end coupled to the packer, and a lower signal line connector positioned below the packer. An upper completion includes a second length of production tubing and an upper signal line connector, the upper completion adapted to make operative connection between the upper signal line connector and the lower signal line connector below the packer.
In an embodiment, the upper completion includes an orientation lug and the lower completion includes an orientation sleeve having a scooped profile, whereby upon movement of the upper completion into the lower completion, the orientation lug follows the scooped profile and rotates the upper completion relative to the lower completion to align the upper connector and lower connector.
In an embodiment, the upper completion includes an alignment nose and the lower completion includes a complementary alignment recess. When the upper completion is lowered into the lower completion, the alignment nose enters the alignment recess and further aligns the upper and lower connectors.
In an embodiment, the upper completion includes a cylindrical outer surface on its lowermost end and the lower completion includes a complementary cylindrical bore. When the upper completion is lowered into the lower completion, the lowermost end of the upper completion enters the complementary bore and further aligns the upper and lower connectors.
In the present disclosure, a first element may be described as upper, above, or uphole relative to a second element, which second element may be described as lower, below or downhole relative to the first element. The top of a well is at the surface of the Earth, which may be below water in a sub-sea well, and the bottom is the end of the well opposite the top, even though the bottom may not be directly below the top and may be horizontally displaced by a substantial distance. Portions of a well may be slanted or even horizontal. In a horizontal well, the first element would still be referred to as uphole or above the second element because it is closer to the surface end of the well.
A general description of an embodiment is provided with reference to
A lower completion 22 has been installed in the well 10 extending downhole from packer 18. The packer 18 may be installed with and as part of the lower completion 22. The lower completion 22 includes a length of tubing 24 which extends down well 10 to one or more productive zones from which fluids may be produced. The produced fluids are desirably produced or flowed uphole through the tubing 24. The lower completion 22 also includes sensors 26, e.g. temperature, pressure, and/or flow rate sensors, and actuators 28 which may, e.g., open and close valves. The sensors 26 and actuators 28 may be connected to one or more signal lines 30 for transmitting sensor 26 outputs uphole and/or transmitting control signals downhole to the sensors 26 and/or actuators 28. The upper end of signal line 30 terminates in a connector 32. In the prior art, the connector 32 was positioned above the packer 18, which packer would include a separate interior flow path for the signal line 30. In this embodiment, the connector 32 is carried on the lower completion 22 and is positioned below the packer 18, so that no separate interior flow path through packer 18 is required for the signal line 30 or connector 32.
On the upper end of tubing 24 is formed an enlarged portion 34, which may be a separate element attached by threaded connections as are typically used to connect oil field tubular elements, e.g. tubing, casing, liners, etc. The portion 34 is referred to herein as the lower carrier or lower connector carrier, because it carries the connector 32 which is part of the lower completion 22. In this embodiment, connector 32 is a female signal line connector or receptacle, for example the female portion of an optical fiber connector system having part number DHCE-B36-BB-01P-000-00 sold by Tronic, Limited. The upper end of the lower connector carrier 34 is connected to an internal flow path 36 through packer 18 mandrel 38 by a threaded connection, although it could be welded to, or formed as an integral part of, the packer 18 mandrel 38.
An upper completion 40 includes a length of tubing 42 which extends from the surface location of well 10 down to the packer 18 and the lower connector carrier 34. An upper signal line 44 is carried on the tubing 42 and also extends from the well 10 surface location down to the lower completion 22 where it needs to be operatively connected to the lower completion signal line 30. On the lower end of the tubing 42 is formed or attached an upper connector carrier 46 which, in this embodiment, carries a male connector 48. The upper connector 48 is connected to the lower end of upper signal line 44 and is adapted for making an operative connection with the lower connector 32, thereby allowing signals to pass between the signal lines 30 and 44. In this embodiment, the upper connector is the male portion of an optical fiber connector system.
The upper carrier 46 includes at least one enlarged portion, or seal body, 50 having seals, e.g. O-rings, on its outer surface and adapted to form a fluid tight seal with an inner surface, or seal bore, of the lower carrier 34. When such a seal is formed, a continuous fluid flow path is formed between the lower completion tubing 24 and the upper completion tubing 42. As illustrated, the enlarged portion 50 also includes a conduit through which the signal line 44 passes. Sealing means, e.g. O-rings or a cured-in-place material such as epoxy or elastomer, is provided between the signal line 44 and the enlarged portion 50 to restrict fluid flow past the portion 50.
Also illustrated in
More details of an embodiment are shown in the following figures. Such details include elements which automatically align the upper connector 48 with the lower connector 32 as the upper completion 40 is lowered into operative engagement with the lower completion 22.
With reference to
The enlarged portion 62 includes several elements which operate to automatically position the upper connector 48 in proper alignment with the lower connector 32 as the upper completion is installed in the well 10. An orientation key or lug 74 is carried in a recess 76 and pivots on a cap screw 78. A spring, not shown, urges the lug 74 to its extended position as shown in
With reference to
With reference to
A lower portion 104 of the mandrel 98 has a larger inner diameter 106 than the upper portion 100. Carried within lower portion 104 is an orientation sleeve 108 having a scooped profile 110 adapted for engaging the orientation lug 74 on upper carrier 46 and rotating the upper carrier 46 into proper alignment with the lower carrier 34 as the upper carrier 46 is lowered into the lower carrier 34.
A collar 112 is attached to the lower end 104 of mandrel 98 by a threaded connection 114 and seal 116. Collar 112 includes a bore 118 within which is carried the lower connector 32. The bore 118 extends through a wall of the collar 118 so that the connector 32 may be connected to the signal line 30 which is carried on the outside of the lower completion. The lower signal line 30 extends from the connector 32 down the tubing 24 as shown in
As illustrated best in
With reference to
In operation, the lower carrier 34 is assembled as shown in
When it is desired to place the well 10 on production, the upper completion 40 must be installed to complete a flow path from the producing zone or zones to the surface. In operation, the upper carrier 46 is assembled as illustrated in
As the upper carrier 46 exits the lower end of the protective sleeve 52, it passes through the packer 18 and enters the upper end of the lower carrier 34. After the orientation key 74 has exited the protective sleeve 52 and passed through the packer 18 and seal bore 102, its spring causes it to deploy into the extended position shown in
As the upper carrier 46 continues moving downhole, two other alignment arrangements precisely align the upper connector 48 with the lower connector 32. The tubing extension 88 enters the upper portion 122 of the collar 112 and provides radial alignment of the connectors 48 and 32. The nose profile 86 surrounding the male connector 48 enters the complementary recess 119 in the collar 112. The nose profile 86 and recess 119 are preferably machined to close tolerance to provide a precise final rotational alignment of the upper connector 48 with the lower connector 32.
Downward movement of the upper carrier 46 relative to lower carrier 32 stops when the face 80 of the upper carrier 46 contacts a surface 113 (
The commercially available connectors 48 and 32 include internal compartments filled with fluid, typically grease, which are adapted to flush away any foreign material as the connectors mate. In this downhole application, the well is normally filled with drilling or completion fluid which may be water or oil based and may include produced fluids such as crude oil, brine, etc. It would normally not be desirable for any conventional well fluids to enter or remain in the connectors 48 and 32. The fluid carried in the connectors will flush the undesirable fluids out as connection is made.
As noted above, the tubing extension 88 on the bottom of upper carrier 46 has an outer diameter that forms a close fit with the inner bore 122 on the upper end of the collar 112. While this is a close fit, it is not a fluid tight fit. At about the same time as the extension 88 enters the area 122, the seal body 50 on the upper end of upper carrier 46 enters the seal bore 102 on the upper end of lower carrier 34 and forms an essentially fluid tight fit, in part because of seals such as O-rings 51. Fluid located between the face 80 and nose area 86 of the upper carrier and the upper end of collar 112 is therefore forced to flow through the close space between the extension 88 and the bore 122 as the upper carrier moves further downward. As the upper carrier 46 moves down, the resistance to flow increases. This arrangement provides fluid damping of the downward motion of the upper carrier 46 as it reaches its lowermost position. This damping reduces the chance of mechanical damage which might be caused by a sudden impact of the upper carrier 46 with the lower carrier 34. The connectors 48 and 32 are relatively delicate as compared to the typical oil field tubulars that form most of the upper and lower completions and this damping of downward motion reduces the risk of damage. As the fluid is flushed out in this final damping of the relative motion, it may also assist in flushing undesirable materials from the connectors 48 and 32 just before they make initial contact.
In the disclosed embodiments, the signal lines 30 and 44 are optical fiber cables. Electrical cables have been used in downhole applications and connectors for electrical cables are available. Electrical cables and connectors may be used in place of or in addition to the optical fiber cables and connectors. Hydraulic lines have also been run downhole for operating downhole valves, motors, etc. and quick disconnects are available for hydraulic systems and may also be used in place of or in addition to the disclosed optical fiber cables and connectors. If desired, more than one set of connectors could be carried on the carriers so that more than one type of signal line may be connected downhole. Multiple types of connectors could be used side by side or in tandem. The present invention is directed primarily to the alignment mechanism which provides precise alignment between the connectors so that they may be properly connected without damage in the severe downhole environment, and not to the particular type of signal lines and connectors.
In some wells, downhole pressures may be able to provide sufficient upward force on the upper completion 40 to lift it up relative to the lower completion 22. If the amount of upward movement should exceed the compression of the spring 72, the connectors 48 and 32 might lose their operative connection. In such wells, it would be desirable to include a releasable latch between the upper carrier 46 and the lower carrier 32. Such a latch would preferable include a shear pin in the upper carrier 46 which would release the latch in response to sufficient upward force on the tubing 42. If the upper completion needs to be removed from the well, the shear pins can be replaced to put the upper completion back in original configuration for running back into the well.
In this embodiment, the upper carrier 46 carries a male connector and the lower carrier 34 carries a female connector. A reason for this choice is that in commercially available fiber optic connector systems, the female connector is larger in diameter than the male connector. As can be seen from the drawings, the upper carrier connector is carried outside the tubing 56 that forms the production flow path and the whole upper carrier must fit through the interior flow path 36 in the packer 18 mandrel 38. As the upper carrier connector size increases, the available production flow path is reduced in size. It is desirable that the upper carrier 46 connector be as small as possible, to provide the largest possible production flow path. Since the lower carrier connector 32 is attached below the packer 18 before installation, it does not have a limiting effect on the production flow path through the packer 18.
In alternate embodiments, the upper connecter 48 may be carried at least partially within the tubing 56 of the upper carrier in the run in configuration. Such an arrangement would permit a larger diameter for the production flow path through tubing 56 for a given diameter of interior flow path 36 through the packer 18 mandrel 38. The upper connector 48 could then be deployed axially after the upper carrier 40 has passed through the packer 18. This alternate embodiment would be more complex than the preferred embodiment, would be more expensive and would have a greater risk of damage and failure. This alternate embodiment would also include the alignment mechanisms of the disclosed embodiment. For these various reasons, the disclosed embodiment maintains the upper connector 48 in a fixed position relative to the upper carrier 46 throughout the run in and connection steps.
While the present invention has been illustrated and described with respect to particular embodiments, it is apparent that various modifications, substitutions, and additions may be made within the scope of the invention as defined by the appended claims.
