Play Implications of the Neogene Tectonic Evolution of the Northern Sakhalin Region

Graham Yielding¹, Bryan Ritchie², Ellen Birkeland², Philip Hirst³, and Alastair Bent^2
1 Badley Geoscience Ltd, Lincolnshire, United Kingdom
² BP, Houston, TX
³ BP, Sunbury-on-Thames, Middlesex, United Kingdom

Sakhalin Island comprises a major petroleum province, with onshore and offshore fields and discoveries containing >5 billion barrels of liquids and c.35 TCF gas hosted in Mio-Pliocene reservoirs associated with the Amur Delta. The delta lies astride an active tectonic zone that links the Kuril-Japan trench to the intra-continental deformation in the Chersky Range of east Siberia.

BP and Rosneft have embarked on a major exploration drive in the Sak IV and Sak V offshore areas around the northern Shmidt Peninsula. Activity in 2004-05 included drilling the successful Pela Lache well and acquisition of a regional 2D seismic program covering Sak IV and V, including the Deriugin Basin to the east. Interpretation of the new seismic data has been integrated with onshore structural studies and an assessment of the active seismotectonics to provide a new understanding of the evolution of the region through the Neogene.

Following the accretion of the Okhotsk region to the Eurasian continent in the Palaeogene, a widespread phase of extension occurred in the late Oligocene to early Miocene. In the early Pliocene a N-S-trending dextral strike-slip zone was established, and exerted significant control on sediment distribution. A significant transpressional component to the movement has resulted in a series of prospective high-level asymmetric anticlines over the NW-SE dextral faults. The tectonic Neogene evolution is characterised by significant changes in the kinematic framework, which have had important effects on local sediment distribution.