“Real Time” Seismic Imaging While Drilling: An Example from a Complex Structure in the Southern Subandean Belt in Bolivia

Abstract

Pre-drill prospect definition in complex thrust belts frequently rely only on poor quality 2D time seismic data. The velocity models used for seismic depth processing and depth conversion of time interpretations usually have very limited borehole information. As a consequence poorly controlled seismic images have a strong impact on the pre-drill structural interpretations of these prospects. In this paper, we present how the borehole information acquired during drilling (sonic, checkshots & VSP) is used to update in real time the seismic image, as well as challenging paradigms about seismic time processing and velocity model building for depth imaging. Several PSDM images were produced and updated after each logging runs, giving more accurate velocities information as input for the velocity model update. As a result, a progressive improvement of the seismic depth image is delivered to the geological team for their structural interpretation during drilling. This “real time” interpretation update is highly valuable in several aspects of the project, from guiding drilling activities to revising prognosis and volumetric calculations, and it delivers robust technical evidence for more accurate operational and economic decisions.

AAPG Datapages/Search and Discovery Article #90326 © 2018 AAPG Latin America & Caribbean Region, Optimizing Exploration and Development in Thrust Belts and Foreland Basins. Santa Cruz de la Sierra, Bolivia, June 6-8, 2018