Permeability Data Treatment from Analogous Outcrop for Use in Three-Dimensional Reservoir Model

Abstract

Over the past forty years, the study of analogous outcrops has become a common practice in the petroleum industry to access more comprehensive geological datasets and better parameterize various geological features. As most reservoirs do not outcrop and all the data obtained are restricted to those collected from wells located in areas of major interest or from indirect measurements, the study of analogous outcrops has brought important contributions to improve the production routines and still represents a helpful information resource. The use of data from analogous outcrops permits, for example, to estimate the sedimentary facies distribution in true reservoirs, and thus to improve on the reliability of fluid flow modeling during the oil field exploration. However, such data must be processed to become equivalent to the data collected under the reservoir conditions and the results obtained to be more realistic. This work presents the statistical method used to make permeability data obtained from an outcrop compatible with the subsurface conditions of poorly consolidated and tectonically deformed sandstone reservoirs. The studied outcrop is predominantly composed of Eocene fluvial sandstones (Resende Formation) of the Volta Redonda Basin, located in the Central Segment of the Continental Rift of Southeastern Brazil. These deposits are affected by deformation bands and faults. From statistical analysis, it was intended that the permeability data become more suitable to be used, in the next phase of the studies, to build a 3D flow model, in which it will be possible to test the potential of different tectonic structures acting as hydraulic barriers in poorly consolidated and deformed reservoirs. The methodological approach applied in this study made it possible to turn compatible the permeability data obtained in conditions of no confining pressures from the outcrop with reservoir conditions under confinement pressures of 2,000 psi. Such pressure conditions are frequently observed in important Maastrichtian reservoirs found in the Brazilian Southeastern Margin.