Statistical AVO Classification in Areas with Diagenesis and Tectonic Uplift - Case Example from the Barents Sea

Abstract

Present day rock physics properties and associated seismic signatures are controlled by burial history, tectonic events and temperature changes, diagenetic alterations and pressure modifications. Hence, in order to fully understand the seismic signatures of a prospect, we should not only relate rock properties to present day geologic factors (porosity, clay content, mineralogy, in situ pressure, etc.), but honour the geologic processes through time (Avseth and Drge, 2011). There are very few studies documenting the effect of complex tectonic and uplift on rock physics and seismic properties (e.g., Brevik et al., 2011). Taking into account diagenesis and tectonic events, we can predict compaction trends and associated seismic velocities in areas with more complex burial history involving both mechanical and chemical compaction, as well as uplift episodes and corresponding erosion. The resulting rock physics trends help us to better constrain AVO inversion and classification under such circumstances. We propose a methodology for statistical classification of fluids and facies in uplifted areas. The robustness of the method was validated by comparing the results to the information obtained from newly drilled well situated near the Loppa High in Barents Sea.