Wells – With electrical means
Reexamination Certificate
2001-07-05
2003-05-13
Pezzuto, Robert E. (Department: 3671)
Wells
With electrical means
C166S338000, C439S191000, C439S140000, C439S201000
Reexamination Certificate
active
06561268
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to underwater or severe environment well installations, connectors and electrical connectors.
In the offshore oil and gas industry it is known to provide at the top of a subsea well a so-called subsea tree. This consists of a vertically extending tubing hanger at the base of the tree, and a valve block connected on top of the tubing hanger. In such known systems, the main oil and gas production bore extends up the well and into the central region of the tubing hanger. In a horizontal subsea tree the production line exits the tubing hanger horizontally and in a vertical subsea tree the production line continues vertically through the valve block. It is usual for the connection of the valve block to the tubing hanger to be made when the latter is already installed subsea.
Any electrical or optical supply lines, for example to carry signals or transmit power to downhole equipment such as electrical submersible pumps, are located in the radially outer region of the tubing hanger, in view of the presence of the production line in the central region. Typically, one or more electrical lines are arranged to extend parallel to and spaced from the longitudinal axes of the tubing hanger and valve block respectively. A pin and socket electrical connector in axial alignment with the respective electrical lines is provided to form an electrical connection between the electrical lines when the tubing hanger and valve block are connected together. Thus, one half of the connector is located on the tubing hanger and the other half on the valve block, and both are positioned laterally spaced from the longitudinal axes of the tubing hanger and the valve block. Consequently, the tubing hanger and valve block must be accurately rotationally aligned to ensure that the two halves of the electrical connector can mate to establish an electrical connection. Such rotational alignment can be difficult in view of the substantial size and weight of the valve block and the fact that the connection is being made on the seabed.
SUMMARY OF THE INVENTION
The present invention seeks to overcome this problem by providing, in one aspect, a well installation which can provide an electrical connection without the need for accurate rotational alignment of the parts of the installation.
Viewed from a first aspect, the present invention provides an underwater or severe environment well installation, comprising first and second installation parts having respective longitudinal axes and being connectible with each other with their longitudinal axes in alignment, a first electrical contact portion on the first installation part, and a second electrical contact portion on the second installation part, the contact portions being laterally spaced from the respective longitudinal axes of the installation parts and being arranged to make electrical contact with each other when the first and second installation parts are connected, such electrical contact being achievable at a plurality of different relative rotational positions of the first and second installation parts about their longitudinal axes, and the first and second installation parts further comprising a well production line extending along their aligned longitudinal axes when they are connected with each other.
Thus, rotational alignment of the installation parts to a single predetermined relationship before connection is not required in order to make the electrical contact between the contact portions, even though they are laterally spaced from the longitudinal axis. In some embodiments, only coarse rotational alignment is required, to one of the plurality of available relative rotational positions. In other embodiments, no rotational alignment is required and the electrical contact can be made irrespective of the relative rotational positions of the first and second installation parts about their longitudinal axes. Both types of embodiment are discussed further in this specification.
The lateral spacing of the electrical contact portions from the longitudinal axes of the well installation parts (which may for example comprise a valve block and a tubing hanger of a subsea tree) leaves a central region thereof free for the production line. This is advantageous in the case of a vertical subsea tree, where the production line continues from the tubing hanger vertically through the valve block. Thus, in one specific use of the invention, the first installation part is a valve block and the second installation part is a tubing hanger and an oil or gas production line is provided on the longitudinal axis of the installation.
The first and second installation parts could take various forms, but preferably at least one of the installation parts comprises an annular member for engagement with the other installation part. It is possible for the other installation part to have any suitable configuration for such engagement, and it may therefore not comprise a complete annulus. It is however preferred for both installation parts to comprise “endless” annular members for engagement with each other. Preferably one of the installation parts comprises an axial projection on which a respective electrical contact portion is provided and the other installation part comprises an annular socket in which the axial projection is engageable. The axial projection may be in the form of a pin or the like which may engage in the annular socket at any point around its circumference. Preferably however the axial projection is an annular projection.
In one preferred embodiment, the first and second installation parts are each made up of four or more radial segments consisting alternately of electrical contact segments and insulative material segments. Thus, where four segments are provided, a two way electrical connection will be formed when at least a partial overlap is formed between each electrical contact segment of the first connector part and a respective electrical contact segment of the second connector part. Some coarse rotational alignment will be required to achieve the partial overlap of the contact segments which are to make electrical contact with each other.
Still more preferably however, the respective electrical contact portions will extend about the longitudinal axis to the extent necessary to ensure that electrical contact will be established irrespective of the relative rotational positions of the first and second connector parts. For example, an endless annular contact portion on one connector part can make contact with a contact portion (or portions) on the other connector part of relatively short annular extent. In the embodiment described above, where one of the installation parts comprises an annular projection and the other installation part comprises an annular socket in which the annular projection is engageable, the respective contact portions may be provided continuously or intermittently about the annular projection and annular socket respectively. In a currently preferred embodiment, the electrical contact portion of each connector part comprises a respective annular contact ring. These rings may for example have laterally extending faces arranged to make contact with each other, or longitudinally extending faces arranged to make contact with each other.
A region is preferably provided in the annular socket where, in the connected state of the well installation, the respective contact portions are in electrical contact. Preferably, the annular socket is sealed from the outside environment when the installation is both in the disconnected state and in the connected state. Sealing means for the annular socket is thus provided. This may comprise a resilient e.g. elastomeric seal which is closed when the installation parts are disconnected and is split open or pushed away by the axial, e.g. annular, projection when it is inserted into the annular socket. As a means of closure, this type of seal may be subject to the problem of “compression set”, preventing full closure upon disconnection after being deformed to
Alix Yale & Ristas, LLP
Beach Thomas A.
Pezzuto Robert E.
Tronic Limited
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