3-D characterization of a clastic reservoir analog: From 3-D GPR data to a 3-D fluid permeability model

A three-dimensional (3-D) 100 MHz ground-penetrating radar (GPR) data volume is the basis of insitu characterization of a fluvial reservoir analog in the Ferron Sandstone of east-central Utah. We use the GPR reflection times to image the bounding surfaces via 3-D velocity estimation and depth migration, and we use the 3-D amplitude distribution to generate a geostatistical model of the dimensions, orientations, and geometries of the internal structures from the surface down to similar to 12 m depth. Each sedimentological element is assigned a realistic fluid permeability distribution by kriging with the 3-D correlation structures derived from the GPR data and which are constrained by the permeabilities measured in cores and in plugs extracted from the adjacent cliff face. The 3-D GPR image shows that GPR facies changes can be interpreted to locate sedimentological bounding surfaces, even when the surfaces do not correspond to strong GPR reflections. The site contains two main sedimentary regimes. The upper similar to5 rn contain trough cross-bedded sandstone with average permeability of similar to 40 Ind and maximum correlation lengths similar to (5.5-12.5) x (3.5-8.0) x (0.2-1.5) m. The lower similar to7 m contain scour and fill fluvial deposits with average permeability varying from similar to 30 Ind to similar to 15 md as clay content increases, and maximum correlation lengths similar to (4.0-12.5) x (3.0-10.0) x (0.5-1.0) m. These representations are suitable for input to fluid flow modeling.