Events

Speaker:  Dr. Dario Grana, Assistant Professor in the Department of Geology and Geophysics at the University of Wyoming

Title of Seminar: “Rocks, fluids, and Bayes’ rule: how to quantitatively characterize the subsurface”

Abstract: Seismic reservoir characterization studies aim to build 3D reservoir models of rock and fluid properties conditioned by geophysical data. Rock and fluid properties can be estimated from seismic data as a solution of an inverse problem, by combining rock physics and seismic modeling with inverse theory and geostatistics. The probabilistic approach to the inverse problem provides the posterior distribution of rock and fluid properties given the measured geophysical data and allows quantifying the uncertainty of the predicted results. The reservoir characterization problem includes both discrete properties, such as facies or rock-type, and continuous properties, such as porosity, mineral volumes, and saturation. To jointly estimate the posterior distributions of facies rock and fluid properties given a set of geophysical data (seismic and electromagnetic), we adopt a Bayesian inversion method under the assumption of Gaussian mixture distributions of petrophysical properties and a Markov chain model for facies. This inversion method can be combined with geostatistical algorithms to generate multiple realizations from the resulting Gaussian mixture random field including a spatial continuity model. Bayesian inversion can also be applied to time-lapse seismic data to estimate the changes of dynamic properties, such as saturation and pressure, during production, and to seismic history matching to update the static reservoir model and obtain more accurate production predictions.

Biography:   Dario Grana is an assistant professor in the Department of Geology and Geophysics at the University of Wyoming. He received a MS in Mathematics at University of Pavia (Italy) in 2005, a MS in Applied Mathematics at University of Milano Bicocca (Italy) in 2006, and a Ph.D. in Geophysics at Stanford University in 2013. He worked four years at Eni Exploration and Production in Milan. He joined the University of Wyoming in 2013. He is coauthor of the book ‘Seismic Reflections of Rock Properties’, published by Cambridge University Press in 2014. He is also the recipient of the 2017 EAGE Van Weelden Award, the 2016 SEG Karcher Award, and the 2014 Eni Award for New Frontiers of Hydrocarbons, together with Tapan Mukerji, Gary Mavko and Jack Dvorkin (Stanford University). His main research interests are rock physics, seismic reservoir characterization, geostatistics, data-assimilation and inverse problems for subsurface modeling.