P247 Sequence Statigraphic Analysis of Achimov Member – West Siberia Central Part of the Surgut Swell I.N. Kerusov (PetroAlliance) S.M. Pustovalova (PetroAlliance) E. Barinova* (PetroAlliance) & R.M. Mansurov (Lukoil-AIK) SUMMARY This work considers the complex-structure Achimov oil/gas play in the territory of central part of the Surgut Swell in West Siberia with acreage of more than 7000 km2 using the approach of sequence stratigraphy analysis. As a result of phase-by-phase correlation of reflectors 5 sigmoid-shape clinoform members – sequences were singled out. Within each sequence in accordance with the diagram of uestatic sea-level changes and downwarping of the basin bottom