EAGE E-Lecture Series

Satellite radar data for surface deformation monitoring are gaining increasing attention. They provide a powerful tool for remotely measuring small surface displacements that can be applied successfully to many different applications, spanning from sinkhole detection to reservoir optimization. This course provides a step-by-step introduction to satellite radar sensors, SAR imagery, SAR interferometry and advanced InSAR techniques. Rather than a tutorial for remote sensing specialists, the course starts from very basic concepts and explain in plain language the most important ideas related to SAR data processing and why geoscientists and engineers should take a vested interest in this new information source.

In recent years, elastic inversion and quantitative interpretation of pre-stack seismic data have become standard procedures in the petroleum industry. In this presentation, Per Avseth (Norwegian University of Science and Technology) compares extended elastic impedance trends at different chi angles, with rock physics template models. He demonstrates that the elastic impedance attribute does not always comply with the complexity and non-linearity of rock physics models related to geological processes. He also shows how one can honour the non-linearity of a rock physics model and create pseudo-elastic impedance as a function of deviation away from a curved water-wet rock physics model itself (CPEI). Finally, Per demonstrates the use of this approach on seismic inversion data from a selected area in the Mid Norwegian Sea, by mapping of lithology and fluid anomalies that are consistent with rigorous rock physics models.

Calin Cosma (Vibrometic) describes the high-resolution seismic techniques, used for rock characterization ahead and around the access tunnel of the spent nuclear fuel disposal facility, currently being built at Olkiluoto, Finland. Long fractures and deformation zones were identified and mapped up to hundreds of meters from the tunnel. The methodological novelty has been the introduction of the 3D Image Point migration, which proved to be very effective for the imaging of low-aperture rock features with various orientations. The results are compared with the current site model and observations in tunnels and boreholes.

Laurent Souche (Schlumberger) exposes the latest advances in structural modeling. After discussing the conceptual differences between surface-based and volume-based approaches for building 3D faulted structural models of the subsurface, the key algorithms underlying the volume-based technology are described. The main geological and geometrical constraints controlling the interpolation of a 3D attribute representing the relative geological age of the formations are also detailed. Finally, advantages of volume-based methods are illustrated using synthetic examples, physical sandbox models and real field data.

Eric Verschuur offers a short version of his EET 1 tour, explaining how multiple reflections influence seismic measurements. An overview is provided of the techniques that were developed to remove them, from the (high-resolution) parabolic Radon transform to the full 3D SRME technique of today. He also discusses the extension to internal multiples and, finally, looks into the future, where multiples could be used as signal in imaging procedures.

Milana Ayzenberg (Statoil) discusses the different aspects of using 4D seismic for conditioning reservoir models. Assisted history matching is employed to match the reservoir production history and the 4D seismic inversion data simultaneously. The three building bricks of a conditioning workflow are the forward modelling from the reservoir model to the inverted 4D seismic attributes; the quantitative seismic inversion; and the history matching which closes the dynamic conditioning loop. Milana discusses in detail these three components, with a particular focus on the quantitative aspects and uncertainties in a 4D inversion. The conditioning workflow is demonstrated on a North Sea field which exhibits a complex 4D signal. The seismic data is inverted to 4D changes in elastic parameters. This data is further used for conditioning the reservoir model on equal footing with production and pressure data.

Bin Wang (TGS) briefly introduces a new imaging algorithm called Least Squares RTM (LSRTM). LSRTM is an inversion-based imaging algorithm, which aims to derive a better reflectivity image. Similar to Full Waveform Inversion, LSRTM is trying to minimize the data residual between a field-recorded seismogram and a synthetic modeled seismogram. Like Reverse Time Migration (RTM), LSRTM is based on the two-way wave equation. Compared to a regular RTM, LSRTM has the following benefits: 1) it gives a high-resolution and broadband seismic image, especially the low frequency end; 2) it reduces migration artifacts due to acquisition foot print and non-uniform illumination; 3) the migration image has more balanced amplitudes, as LSRTM is towards true amplitude imaging.

Per Avseth (Norwegian University of Science and Technology) discusses Rock Physics and Seismic Reservoir Prediction Constrained by Depositional and Burial Trends. Outline: 1. Rock physics background and motivation. 2. Using compactional depth trends to improve lithology and fluid classification from AVO - a demonstration from the Alvheim field, North Sea. 3. How burial history and associated variation in rock stiffness affects 4-D time shifts - An example from the Troll East field, North Sea. This is a compact version of Per Avseth's Distinguished Lecture Programme presentation.

Jorg Herwanger (IKON Science, previously Schlumberger) discusses the process of building and calibrating geomechanical models using 3D and 4D seismic data. He analyzes the three main uses that seismic data provide in building geomechanical models: horizon and fault interpretation for building structural models, AVO inversion and rock physics models for creating mechanical property models, and for model calibration. Herwanger elaborates on these three points in two case studies. The first case study presents a 3D exploration geomechanical model. The second study presents a 4D geomechanical model used for field development planning. This is a compact version of Jorg Herwanger's EAGE Education Tour (EET 5) short course series.