Ice-free period in the southwestern part of the Kara Sea is limited in average to 2-3 months and has significant interannual variability. A preliminary assessment of the ice-free period duration will allow advanced strategic and tactical planning of platforms operating and drilling activities and, thus, costs optimization of exploration drilling. Duration of ice-free period depends on the date of the sea clearing from the ice and on the date of the stable ice formation. Data analysis was based on historical ice maps and satellite information for a 30-year period from 1989 to 2018. Interannual variability of ice free periods, dates of sea clearing from ice and dates of ice formation are considered in the region of geological structures of the southwestern part of the Kara Sea. It is shown that combination of favorable hydrometeorological conditions that in the last decade increased the ice-free period duration by more than a month. Aanalysis of the main hydrometeorological factors determining ice-free period duration showed possibility to estimate the operational window for exploration drilling in the area of geological structures with a lead time of several months.
East Prinovozemelsky license blocks are located in the southwestern part of the Kara Sea between the Novaya Zemlya archipelago in the west, Yamal peninsula in the south and the Taimyr peninsula in the east. The northeastern border of the sea is an imaginary line between the Cape Zhelaniya and the Dickson Island. Several prospective geological structures have been identified within the boundaries of these license blocks (Fig. 1), and in 2014 the Pobeda field was discovered during exploration drilling at the Universitetskaya structure.
Usually exploration drilling in freezing seas is carried out in the ice-free period from floating drilling rigs of various ice classes. In the southwestern part of the Kara Sea the ice-free period is limited in average to 2-3 months (Atlas, 2014; Monograph, 2004) and has significant interannual variability.