STUDY OF ICING-UP IN THE FRESH WATER TANKS OF THE SEMI-SUBMERSIBLE DRILLING RIGS OPERATED IN NORTHERN SEAS

摘要

A design feature of some semi-submersible drilling platforms (for example, Moss CS-50) is placement of tanks with fresh water immediately adjacent to the outside shell or ballast tanks. To determine whether operation of such rigs is possible on gas and oil fields in northern seas where the water temperatures are about -3°C and the air temperatures are about -30°C, assessment of the extent of icing on the inner surfaces of such fresh water tanks is necessary. The report presents the procedure of computing the ice formation on fresh water tanks surfaces, with account for special features of free convection at inversion of water thermal expansion coefficient in the temperature range from 0 to +4°C, thermal effectiveness of the framing and water exchange. The results have been obtained on the thickness of the ice layer on the inner surfaces of fresh water tanks of the Moss CS-50 in the Barents Sea.