Johan Sverdrup Imaging Part 1: PS Velocity Model Building and RTM Imaging
H.M. Zadeh, S. Gupta, S. Winterstø, E. Sadikhov and M.S. Guttormsen
Event name: 81st EAGE Conference and Exhibition 2019
Session: FWI Case Studies I
Publication date: 03 June 2019
Info: Extended abstract, PDF ( 915.45Kb )
Price: € 20
Converted wave (PS) imaging of an ocean bottom node survey over the Johan Sverdrup field on the Norwegian continental shelf was performed to evaluate the potential of shear waves for reservoir characterization, further structural improvement and future direction on PS permanent reservoir monitoring (PRM) data. The PS image provided a reasonable tie to the PP image. However, the presence of the high-velocity chalk layer, generates complicated mode conversion below and makes the PS image challenging, thus resulting in a poorer image below chalk as compared to the PP image. This could be partly resolved by using PS reverse time migration (RTM) for imaging as it can handle multipathing and partly mode-converted events better than Kirchhoff. To improve the PS image further, a more detailed model building using well information for both P- and S-wave velocities and multilayer tomography using RTM subsurface azimuth angle gathers for P-wave velocity was required below chalk. As a result, the PP/PS image was significantly improved. Despite significant effort, the PS image did not impart extra information compared to PP image for reservoir imaging in Johan Sverdrup field.