Deepwater pipeline intervention work with an acoustically controlled power module
The stabilization of submarine pipeline free spans along uneven sea bottoms is performed conventionally using technologies such as gravel dumping, post trenching, and mattress installation. A new technology has been developed to support free spans along the 26-inch Transmed Gas Pipelines crossing the Sicily Channel in water depths ranging from 50 m to 510 m. This technology is based on the pipeline mechanical support Atlantis and its installation module Pegaso and was developed keeping requirements such as short installation time, system redundancy, operational flexibility, and simple interface with the support vessel in mind. The installation time reduction is achieved by automatic operational procedures that are controlled acoustically from the surface. Power is stored inside two dedicated battery packs placed on board pegaso; no umbilical cable is necessary, so that a vessel equipped with a normal crane is enough to launch and operate the system. Marine operations carried out in 1993 showed that a support can be installed in about 1 hour. In good weather conditions, three Atlantis were installed in 24 hours, including deck operations for recharging the battery packs. A total of 16 supports was installed along the 4th and 5th Transmed Gas Pipelines. The system has proved to be a cost-effective and flexible alternative to conventional technologies for free-span support, especially in deep waters. A cost/benefit analysis also shows the break-even point of the new technology vs. gravel dumping.
- Sponsoring Organization:
- USDOE
- OSTI ID:
- 435714
- Journal Information:
- SPE Production and Facilities, Vol. 12, Issue 1; Other Information: DN: Paper presented at the 1995 SPE Western Regional Meeting, Bakersfield, CA (US), March 8--10, 1995; PBD: Feb 1997
- Country of Publication:
- United States
- Language:
- English
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