Communications: electrical – Wellbore telemetering or control – Pulse or digital signal transmission
Reexamination Certificate
1998-11-17
2001-06-26
Horabik, Michael (Department: 2635)
Communications: electrical
Wellbore telemetering or control
Pulse or digital signal transmission
C340S855500, C340S855300, C375S229000, C375S219000, C375S233000
Reexamination Certificate
active
06252518
ABSTRACT:
BACKGROUND
The invention relates to communications systems having multiple nodes used in wells.
After a wellbore has been drilled, various completion operations may be performed in the wellbore, in which equipment including packers, valves, flow tubes, and other devices may be set to control fluid production from one or more zones in the well. With advances in technology, sensing and control devices may be placed downhole to monitor and to adjust conditions downhole as needed.
An example system that monitors downhole conditions may include various downhole gauges and sensors that are capable of monitoring temperature, pressure, and flow information. Using a communications link, such as an acoustic data link or a digital telemetry link, data gathered by the gauges and sensors may be sent to the surface to control boxes. The data may then be processed to determine the conditions downhole so that production may be improved and potential reservoir problems may be avoided. In addition to gauges and sensors, other downhole systems may include control devices that may be used to adjust equipment settings downhole.
The communications link between the surface and the downhole equipment is typically a very long link. Conventionally, the link is in the form of one or more electrical wires coupling the downhole equipment to the surface equipment, and the length of the one or more wires may be thousands or tens of thousands of feet long. In addition, the links are associated with transfer characteristics. Consequently, signal attenuation and distortion may occur when the signal is transmitted over a link, which may result in communications errors.
Some communications systems have implemented mechanisms to counteract the distortion effects of cable lines. However, a need continues to exist for improved methods and apparatus for reliable communications between devices coupled to communications lines.
SUMMARY
In general, according to one embodiment, a system for use with a well includes a surface device, a communications link coupled to the surface device and extending into the well, and a plurality of downhole devices coupled to different points on the communications link in the well. The surface device and the plurality of devices are adapted to determine signal distortions in different portions of the communications link coupling the surface device and downhole devices and to compensate for the signal distortions during communication.
Other features will become apparent from the following description and from the claims.
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Horabik Michael
Schlumberger Technology Corporation
Trop Pruner & Hu P.C.
Wong Albert K.
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