UNIQUE TOOLS SURVEYED THE CONDITIONS FOR A SUBSEA LINE

Unique tools surveyed the conditions for a subsea line for British Petroleum Co. Ltd.'s Forties field, which is more than 100 mi from the east coast of Scotland, in water depths of over 400 ft, with wave heights up to 60 ft. The depth configuration of the seabed was determined by a vessel fitted with a precision echo sounder, a high-resolution, continuous-reflection profiler, and an asdic, or side-scan sonar. Near-seabed tidal currents were measured with self-recording current meters, each mounted in a frame that sits on the seabed, above which is mounted an acoustic release, a buoy, and about 1000 ft of nylon rope; the unit is lowered by a special cable, from which it is disengaged electrically; retrieval is accomplished by first relocating the position by means of a suitable radio-navigation aid, such as Decca Hi-Fix, and by sending acoustic signals into the water from a tuned transmitter lowered from the survey vessel to release the buoy to water surface. The height and period of the waves were measured with a spherical buoy containing an accelerometer which responds to wave-induced motion and a radio transmitter which telemeters the resultant data for distances up to 30 mi and for up to 9 months.

  • Availability:
  • Corporate Authors:

    Petroleum Publishing Company

    211 South Cheyenne, P.O. Box 1260
    Tulsa, OK  USA  75221
  • Authors:
    • Caston, V
  • Publication Date: 1972-5-8

Media Info

  • Pagination: p. 76-77
  • Serial:
    • Oil and Gas Journal
    • Volume: 70
    • Issue Number: 19
    • Publisher: PennWell Publishing Company
    • ISSN: 0030-1388

Subject/Index Terms

Filing Info

  • Accession Number: 00056198
  • Record Type: Publication
  • Source Agency: American Petroleum Institute
  • Files: TRIS
  • Created Date: Jul 15 1974 12:00AM