4-D Petrophysical Seismic Inversion on the Troll West Field

K. G. Gjerding, N. S. Skjei, A. N. H. Norenes Haaland, P. R. Riste, T. C. Coléou, I. M. Machecler
2008 70th EAGE Conference and Exhibition incorporating SPE EUROPEC 2008   unpublished
Inversions of seismic surveys often give quite low-resolution results that are difficult to compare with well data and geological models. We are therefore developing a multi-vintage seismic inversion based on a Petro-Elastic Model (PEM), called PetroSI-4D. This involves input from the geological model and good control on the petrophysical correlation between porosity and PEM-based seismic velocities. All vintages and input angle stacks are combined to jointly invert for layer thickness, rock
more » ... perties and saturations. Perturbations of selected properties of the geological model are introduced using a simulated annealing algorithm to optimise the degree of match between the synthetic and the real angle stacks. There are no restrictions on number of input angles or number of monitor surveys, but new monitor surveys require new input to 4-D PEM. The base inversion result is delivered in porosity cubes instead of ordinary acoustic impedance and Vp/Vs results. The 4-D inversion result is planned to deliver saturation cubes instead of cubes of acoustic impedance or Vp/Vs changes. These parameters should be easier to compare and use in update of geological and reservoir models to validate the results. The Troll West Field shows that the Petrophysical seismic inversion with rock physics PEM connected to the inversion, gives good results and comparison with the porosity input model is shown. The purpose of 4-D petrophysical inversion is to make use of all available seismic data simultaneously, multi-vintage and pre-stack, to constrain the evolution of the saturation field.
doi:10.3997/2214-4609.20147814 fatcat:fizbz2dnsjg3vom5venwcntm2u