ABSTRACT: Specific Features of Hydrocarbon Localization in Sedimentary Basins of Northeast Asia

BELONIN, MICHAEL D., and YURY N. GRIGORENKO, VNIGRI, Saint Petersburg, Soviet Union

The majority of sedimentary basins with proved or supposed oil and gas in the region are marine or shore-shelf basins. The report considers the conditions and specific features of petroleum objects located on the regional and zonal levels, and their relations with particularities of structure and development of the zone.

Main features of this zone are (within the Soviet Union): system of actual geosynclines including beyond-arch depressions; megadepressions similar to the Okhotsk sea, where near-folded, periclinal and graben deeps are distinguished; passive part of the active margin-Bering quasi-plate; Cenozoic folded structures of the Kamchatka, Sakhalin, and Koriakian uplift. Sedimentary basin classification concerning subsoil riches have been substantiated based on these features, the structure and development, as well as morphogenetic peculiarities of the transitional zone in general.

The largest sedimentary basin with the highest resource concentrations (in average up to 40-50 th. t/sq km) are located in outlying areas of megadepressions along their boundaries with Cenozoic folded mountain structures. These respond to periclinal and near folded deeps of zone and mainly embrace shelf and adjacent deep water depressions Tinro and Deriugin, as well as some adjacent offshore areas.

Considerable basins with middle resources and moderate specific concentrations (15-25 th. t/sq km) are characteristic of deeps and depressions of passive area of the margin. Relatively small but numerous sedimentary basins relate to synclinoriums and intermontane deeps of Cenozoic folded systems. The perspectives of sedimentary basins in deep-water zones are minimum or unsure, but there are the grabens of central areas in megadepressions, depressions, and frontal deeps in geosynclines. Calculations show what sedimentary basin classifications confirm the possibility of discovering different zones of oil and gas accumulations. Main sedimentary basins of this region (Okhotsk-North Sakhalin, Pre-Kamchatian, Anadir, and North Okhotsk) contain considerable amounts of proven and prospective etroliferous zones with resource densities of up to 300 th. t/sq km. Most of the oil and gas is concentrated in several zones, mainly offshore, where the first big fields have been discovered.

AAPG Search and Discovery Article #91015©1992 AAPG International Conference, Sydney, N.S.W., Australia, August 2-5, 1992 (2009)