Christophe Ribeiro

Estimating subsurface stress direction and intensity from surface full azimuth land data.

Summary Having indicators of stress direction and intensity is a valuable exploration tool especially in unconventional plays. Observations using full azimuth land data will be presented here and also compared to field observations. We show that by splitting the data into azimuthal sectors, provided very moderate dip, alignment and amplitude of the reflections indicates azimuthal anisotropy. We will also show that phase and well ties improve with azimuthal processing. Observations can be made on velocities, but are limited by filtering and vertical resolution. Interval velocities indicate azimuthal variations, but these methods can only be used as a first order observation, and should be confirmed by AVOA. Wells have been drilled in our study area where anisotropic seismic attributes compare favorably with FMI scans.

Time-lapse simulator-to-seismic study - Forties field, North Sea.

Summary A Simulator-to-Seismic (S-to-S) study is conducted over the Forties field, North Sea, by combining petrophysical, engineering and geophysical data into an integrated workflow. Based on a calibrated rock physics model, static and dynamic properties from a reservoir model are converted into time-lapse synthetic seismic attributes that can be used in conjunction with conventional seismic attributes to get more insights into the interpreted 4D anomalies. The aim of the study is to better understand the drainage patterns of the reservoir and help validate the planned position of additional producer wells to ultimately reduce drilling risks.

A Petroelastic-based Approach to Pressure And Saturation Estimation Using 4D Seismic

A042 A petroelastic-based approach to pressure and saturation estimation using 4D seismic Abstract 1 A methodology is developed to invert for time-lapse variations of reservoir pressure and saturation from repeated P-wave seismic data. Based on a simplified petroelastic correlation two independent elastic parameters are obtained; one of which depends on pressure and the other on saturation. Forms for reflectivity and elastic impedance explicitly dependent on production effects are derived and tested on a reservoir model-based study. Following the inversion of multi-angle near mid and far elastic impedance stacks from the baseline and repeat seismic dataset reliable dynamic estimates of pore