ANALYSIS OF THE INCLINATION TESTS OF SEMI-SUBMERSIBLE DRILLING RIGS AND WAYS TO INCREASE THEIR ACCURACY

摘要

Recently the increasing number of lost Semi-submersible Drilling Rigs (SSDR), due accidents on board, begins to attract special attention to their safety. A typical modern-day rig is usually very expensive (200-400mil. USD) and always has a lot of people on board (up to 300) - a fact which could potentially justify to set their safety standards as high as on Passenger ships. Stability control of the rig forms a large part of its operational safety, the effectiveness of which is highly dependent on an accurate and reliable Inclination Experiment. Due to the specific configuration of the hulls and certain exploitation specifics of rigs, the Inclination Experiment (IE) of SSDR is the different from a conventional ship's IE in several aspects. These include the special approach to accuracy and to selection of draft, the direction of inclination and the techniques of inclining the rig, some aspects of the Lightship weight and Variables definition, preparation of Hydrostatic and Tank Sounding Tables and etc. This article discusses these features, their influences on techniques of IE and suggests several ways of increase the effectiveness of the Experiment. Only techniques and procedures, specific to SSDRs are analyzed in this article.