The Unique Experience of Odoptu-more Field Development – A New Stage in Russian Offshore Projects

摘要

The paper deals with the unique experience of Odoptu-more (Northern dome) field development by Rosneft. The field is located 5-7 km from the Shore of Sakhalin Island under the Sea of Okhotsk waters. Onshore extended-reach wells (ERW) with horizontal section are drilled in severe arctic conditions. Similar ERD technology is used worldwide: in the North Sea (BP, Wytch Farm) [1], for example, on South China Sea shelf, at Tiera del Fuego coast (Total, Hidra field) [2]. The successful experience of extended-reach drilling (ERD) gained by Rosneft since 1998 was adopted in 2003 by Exxon Neftegaz Ltd. – Sakhalin-1 Project consortium operator – who revised his initial plans of using expensive fixed sleetproof offshore platform and started Chayvo field development applying onshore ERW [3]. The paper describes the results of geosteering of ERW with up to 800 m long horizontal section in 3-4 m layer at 1500 m TVDSS. Horizontal displacement of 6000 m is typical for this wells. ERD in such geological conditions is a very delicate job considering geological uncertainties related to structure dip angle variation and reservoir discontinuity. It is the first successful application of ERD on the Russian shelf. Moreover, paper touches upon the optimal object development pattern reasoning. Main design solutions that helped to avoid a number of problems connected with subsurface geology and technological restrictions are described.