Abstract

The goal of any time lapse 3D (4D) seismic survey is to detect the changes in the reservoir (pressure, fluid saturation, movement of fluid contacts, temperature etc.) due to production effects on the reservoir state. It is therefore essential to minimise differences in the seismic data due to acquisition and processing differences, environmental differences etc. One of the key factors in minimising differences between successive 4D surveys is the ability to record traces with identical source-receiver azimuths for both base and monitor surveys (i.e. with high repeatability). We will show that an extremely high degree of repeatability is possible by acquiring overlapping coverage between adjacent sail lines. We will also consider the benefits of overlap shooting in minimising primary and/or secondary infill requirements.