Xavier Janson, Sergey Fomel, 2011. "3-D Forward Seismic Model of an Outcrop-Based Geocellular Model", Outcrops Revitalized: Tools, Techniques and Applications, Ole J. Martinsen, Andrew J. Pulham, Peter D.W. Haughton, Morgan D. Sullivan
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Because of their fast acoustic velocity, their ability to create steep slopes, and their important postdepositional diagenetic modification, carbonate rocks are notoriously more difficult to image and interpret using seismic than siliciclastic rocks. This paper shows how building a 3-D synthetic seismogram based on well-constrained outcrop-based 3-D geocellular models can help in seismic interpretation and seismic-based reservoir characterization. Workflow to populate a 3-D geological model with velocity is presented that is based on building statistical distribution of velocity per facies or lithostratigraphic units or diagenetic features and extrapolating velocity through the model using stochastic Gaussian simulation. A 3-D model built from Lower Permian deep-water carbonate gravity flows is used to demonstrate the complexity of interpreting intricate 3-D geometries using 2-D planar seismic slices and to assess volumetric error associated with the intrinsic resolution loss of seismic. Modern karst morphology is used to assess the seismic response of caves, sinkholes, or karst topography in seismic. Finally, a Permian dolomitized ramp-crest grainstone complex is used to test the sensitivity of prestack techniques to pore-type changes in grainy carbonate rocks. These few examples illustrate the strength of building a well-calibrated 3-D synthetic seismogram based on a 3-D geocellular model so that some of the complexity of seismic response of carbonate rocks might be unraveled.
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Outcrops are fundamental to everything we hope to achieve in geological understanding. They are gateways to geological processes, earth history and they help ground-truth remote sensing applications. With increasing resolution of subsurface tools and techniques, one could be forgiven in believing that outcrops have had their day and their utility is less than in the past great eras of field mapping and the development of facies models. This premise is far from the truth and this new SEPM volume illustrates how new analytical techniques are revitalizing outcrops and in the process creating a wealth of new data and fresh geological understandings. In this book you will find a compilation of the growing arsenal of outcrop tools and techniques and a consideration of future developments. This collection of papers, delivered at a SEPM Research Conference on the West coast of Ireland in the summer of 2008, is a smorgasbord of case studies, workflows, modeling, and applications which spans clastic and carbonate settings. Whatever your interest in outcrop geology and its application there is something in this volume for you. If you are seeking guidance for using new outcrop tools, looking for efficiencies in data collection or desiring new insights for old and favorite outcrops, this volume is a must have. This volume also makes an excellent reference or textbook for any group of professionals or students working or studying the new technologies that have allowed new insights from outcrops. We also consider this a superbly timed publication because many new outcrop tools are now becoming mainstream via reduced purchase and operating costs. Once you read this volume, and there are reduced prices for SEPM members and students, please share your new experiences with the authors and editors and help continue the revitalization of our shared and continually surprising outcrop library of the earth.