The effectiveness of the offshore oil and gas deposit exploration in freezing seas depends on ice conditions of basin and ice loads on offshore structures. The ice loads have a random character and errors connected with incorrect evaluation of its probabilistic characteristics, which in many cases can considerably exceed errors of physical models of sea ice and ice forces on offshore structures. On the base of developed computer complex, combining two simulation models, the probabilistic characteristics of ice loads from drifting ice cover on the platform Molikpaq for Sakhalin conditions were obtained. The observation data of ice conditions on the Sakhalin offshore were used.
The exhaustion of oil and gas resources in areas of its traditional exploration causes necessity of the shelf oil and gas deposits development, more than 70% of which are in freezing seas. So, the definition of ice loads on offshore structures is the important problem. The ice load in the Design Codes of Russia (SNIP, 1989) is determined without the sufficient consideration of probabilistic characteristics of parameters, that leads to ambiguous treatment of values of ice loads. The exploration problems of oil and gas deposits on the Sakhalin offshore have been studied since 70-th. The observations of a hydrometeorological regime and ice conditions of the series of perspective fields were carried out, the various constructive versions of ice-resistant platforms were developed, and also the studies of ice and wave loads, physical and mechanical properties of ice were carried out. The ice loads are the basic constraining factor on Sakhalin offshore. The first ice-resistant platform Molikpaq have installed in September, 1998 on field Piltun-Astokhskoye The authors developed the simulation models of drifting ice fields action on ice-resistant platforms on the base of which the probabilistic characteristics of ice loads were found.
