Increasing the Reliability of Geological Models of Complex Fluvial Deposits Based on Spectral Decomposition and Interactive Analysis of the Seismic Data

Abstract

The objective of this study was to build a true aesthetic representation of a complex geological channel to deliver a more accurate geocellular model, by transferring the level of detail that can be captured from the seismic into the geocellular model. A key feature of the work scope was to utilise a Geological Expression interpretive approach for the three-dimensional geomorphology identification of the Eskdale channel itself. This approach involves a series of successive transformations of the seismic signal to maximize the limits of perception of geological information that is potentially present in the data. Depending on the task it may include noise reduction procedures, standard and high-definition frequency decomposition, colour blending, edge detection procedures, geobodies extraction and interactive seismic facies classification respectively. The development of a geocellular model of the Eskdale Channel was carried out in three key stages: - Structural analysis and fault interpretation using edge detection and CMY blending - Seismic Facies analysis, geobody delineation and facies characterisation, using frequency decomposition and RGB blending and interactive facies classification - Creating the geocellular model and property distribution using seismic facies to control the lateral propagation This new approach to the integration of information from seismic data into the reservoir model results in a more accurate model with greater confidence in the property distribution away from the well locations. Spectral decomposition techniques and RGB blending applied to fluvial deposits in the Eskdale formation allowed us to distinguish fine details of the inner structure and morphology of the object not seen in the reflectivity data. The level of true geological representation in the final geological model was promoted by the inclusion of the top and base of the channel, as well as the use of seismic facies trends based on the frequency decomposition. The additional features incorporated from the seismic data were effective at tracking the spatial distribution of key reservoir petrophysical properties in further analysis of the Eskdale Channel.

AAPG Datapages/Search and Discovery Article #90217 © 2015 International Conference & Exhibition, Melbourne, Australia, September 13-16, 2015