| East Sakhalin-Okhotsk Basin has experienced three tectonic evolution stages, rifting, extension and inversion stages. It is shown that during the extension stage, three sets of excellent source rocks developed, including Upper Oligocene Dae-Khurye mudstone, Lower Miocene Uyni-Dagi coal series and Middle-Upper Miocene Okobykai-Nutovian mudstone source rocks. Confirmed by drilling data, three favorable reservoir-cap assemblages are then distinguished. Most of reservoirs consist of marine deltaic sandstones with good reservoir property. Tectonic movements during the inversion stage made a group of structural traps, structural-lithological traps and other typed traps develop in the basin. Good match of the source-reservoir-cap assemblages with hydrocarbon generation and migration decides good conditions of hydrocarbon accumulation for the basin. Excepting most of discovered fields in the western part of the basin, it is suggested that the prospective structural areas are offshore Audopukin Uplift, South Audopukin Uplift and the uplift zone in Chayvo Depression in the eastern part of the basin, as well as onshore Aukha Uplift and Tamlev Uplift. |
