Application of Volumetric 3-D Seismic Attributes to Reservoir Characterization of Karst-Modified Reservoirs
Charlotte Sullivan, Susan Nissen, Kurt Marfurt, 2006. "Application of Volumetric 3-D Seismic Attributes to Reservoir Characterization of Karst-Modified Reservoirs", Reservoir Characterization: Integrating Technology and Business Practices, Roger M. Slatt, Norman c. Rosen, Michael Bowman, John Castagna, Timothy Good, Robert Loucks, Rebecca Latimer, Mark Scheihing, Hu Smith
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Reservoir production and compartmentalization in many karst-modified reservoirs can be related to features resulting from subaerial weathering, tectonic faulting and fracturing, and/or hydrothermal processes. Critical features relating to reservoir character are often subtle and are difficult to image with standard seismic attributes. We have developed new 3D seismic-based geometric attributes that, calibrated with geologic and engineering data, have the potential to image and quantify karst-modified reservoir features at an interwell scale not previously possible. Our aim is to develop innovative seismic-based methodologies and workflows for reservoir characterization of karst-modified reservoirs.
We have applied our new seismic attributes to reservoirs in Kansas, Colorado, and Texas that represent a diversity of ages, lithologies, karst processes, and porosity/permeability systems. In these reservoirs, we have mapped horizon structure, faults, and fractures with a combination of conventional seismic data, coherency, and new volumetric curvature attributes. Using horizon extractions and time slices, we have imaged the geomorphology of eroded surfaces and identified subtle attribute lineaments associated with faults and fractures that relate to reservoir production and compartmentalization. We predict azimuths of open and closed fractures by matching rose diagrams of attribute lineaments with strain ellipsoids, by calibrating to wellbore data, and by relating attribute lineaments to produced fluid volumes. We use improved spectral decomposition and acoustic impedance inversion technologies to image porosity variations in the reservoir.
Our attribute-based structural and stratigraphic models, populated with borehole and engineering data, serve as the basis for improved geomodels that we validate with reservoir simulation.