Layered Acoustic Impedance Inversion applied to the Ewan field, Offshore Nigeria

Summary Seismic data have a key role to play in the process of reservoir characterisation which is a common problem to all phases of the Exploration and Production cycle. Here we present the application of impedance inversion to the Ewan field of the Niger Delta, offshore Nigeria. Key points of the study include: • The Ewan field is a roll-over anticline, fault bounded on three sides and comprises an alternating sand/shale sequence. • A unique, layered approach to acoustic impedance inversion yields high resolution identification of the main sand sequences without high constraints at well locations. • Visualisation and mapping of the spatial extent and quality of the main reservoir sands has enabled targeting of new horizontal wells.