| Deepwater Drilling Risers
ATI has been funded by major oil companies to
use fiber-optic sensors to monitor strain, vibration, and fatigue of drilling equipment in
deepwater (more than 7,500 feet). This project is located offshore in the Gulf of Mexico.
The ATI sensors provide real-time measurements and will allow increased service life for
sub-sea equipment. Significant cost advantages will result from the application of this
technology. Prior to this project, there was no feasible method to measure fatigue cycles
of the drilling riser. Until now, service life of deepwater equipment has always been in
question, especially when operating in high water current environments. Equipment failure
would be catastrophic. Significant costs would result due to long down time required for
riser repair or replacement and subsequent damage to the well head. Potential hydrocarbon
spillage is a concern if the well head is damaged. Real-time monitoring of a fully
instrumented riser will allow for the identification of impending structural damage or
failure due to vortex induced vibration (VIV), providing an immediate response capability
not previously available. |
Fiber-optic sensors allow real-time monitoring of
deepwater drilling risers, providing an immediate response capability.
|
| Fiber-optic sensors were chosen because of
their multiplexing capability, immunity to electromagnetic interference (EMI), and
capability to instrument long distances without signal loss. For example, hundreds of
sensors will be placed along a 7,500-foot riser at 500-foot intervals and a single cable
will be used that contains only 20 fiber-optic strands. This work was conducted on-board a deepwater drilling ship. Data
acquisition was accomplished with a specially designed interferometer. The sensors detect
and reflect a certain wavelength of light within the interferometer’s bandwidth. When
strain is introduced, the sensor wavelength shifts. This wavelength shift is directly
related to strain. |
Fiber-optic sensor work was done on-board a
deepwater drilling ship in the Gulf of Mexico.
|
