AAPG Bulletin, V. 83 (1999), No. 12

AAPG FOUNDATION PRATT CONFERENCE: PETROLEUM PROVINCES, 21st CENTURY
January 12-15, 2000
San Diego, California

RICHARD J. POWELL, Exxon Neftegas Project Services Inc., Houston, TX

Abstract: Future Petroleum Potential of the Northeast Sakhalin Shelf

The Northeast Sakhalin Shelf represents a world-class future petroleum province appropriately positioned for key markets in Japan and China. Discovered undeveloped resources in several giant fields total approximately 3 BBO and 30 TCF. Undiscovered potential could exceed the discovered volume. The framework of hydrocarbon accumulations over the present-day shelf reflects the relationship between tectonics, eustacy, and migrating fluvial-deltaic depocenters.

A backarc basin formed in the Oligocene in response to subduction along the Japan and Kuril arcs. During a period of relative tectonic quiescence, remnant Paleogene tectonic relief focused paleo-Amur River sedimentation into major delta systems, represented by the Miocene Dagi and Miocene-Pliocene Nutovo formations. Basin subsidence was interrupted in Late Pliocene-Early Pleistocene by a transpressional event generating the large anticlines which now constitute the major present-day traps of the Sakhalin shelf.

Seismic stratigraphy documents early eastward progradation of Dagi shallow marine deltaics followed by aggradation and retrogradation, and defines a similar eastward progradation of the Nutovo delta. Stacked, reservoir quality Dagi and Nutovo sands on the western shelf represent highstand stream mouth bar/delta front deposits. Dagi and Nutovo reservoirs are prolific, with gas test rates up to 160 MMCFD, and oil test rates up to 12,000 BOPD.

The high potential future exploration arena is located on the eastern shelf, where numerous large, untested Dagi and Nutovo structural traps are present which are analogous to the adjacent discoveries.

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