Offshore Shipping Online

A publication for the offshore shipping industry published by Clarkson Research

  • Offshore Intelligence Monthly
  • Menu

    Cutting the cost of LBL installation

    Projects and Operations // August 15, 2003
    Cal Dive, Thales Geosolutions and Kongsberg Maritime have more details about a project they embarked on earlier this year which was designed to cut the time and cost spent on Long Baseline (LBL) installation, calibration and equipment used. The theory was tested on matrices installation in the Gulf of Mexico for the Green Canyon field.

    The HiPAP system on the vessel was upgraded to full LBL and a remote computer installed for the survey crew to interface the subsea transceiver on the ROV for LBL and the HiPAP 500 system. This meant that the topside equipment was already installed on the vessel cutting the need for additional equipment.

    The next phase was to review existing procedures on calibrating LBL acoustic arrays. The traditional "Box-in" and baselines is time consuming in both vessel time and manpower for processing the data. A geographic calibration method was decided on which utilises the collection of DGPS, Heading, LBL ranges and the high accuracy acoustic angles the HiPAP could detect.

    The result of this method was that calibration of the LBL array (water depth 1030m) was cut to two hours from the traditional six to eight hour. The absolute accuracy of ROV position was determined to be well under 0.5m. Kongsberg Maritime supported thejob through their Operation Support department and provided training for Thales Geosolutions.

    More articles from this category

    More news