Uso de imágenes de pozo para la caracterización paleoambiental de reservorios y sU aplicación en la indUstria: Un caso de estUdio en el yacimiento cañadón vasco, provincia de santa crUz, argentina

FERREIRA, L.; GRIGNOLA, S.; GÓMEZ SOTO, N.; GEORGIEFF, S.M.

Mar del Plata

Congreso; VIII Congreso de Exploración y Desarrollo de Hidrocarburos; 2011

Instituto Argentino del Petróleo y del Gas

La paginación del trabajo es: 241-260, el archivo pdf excede el límite permitido para la carga y por eso sólo se incluyen las páginas del principio y final. The Cañadón Vasco oil field is located in the southern border of the Golfo San Jorge Basin (Argentina); near by, the Ballena Hills shows extensive fluvial deposits belonging to Bajo Barreal Formation. Thus, a stratigraphic correlation between them was proposed by using seismic lines. The Ballena Hill and the Cañadón Vasco oil fields show a strong tectonic control produced by a NW-SE normal fault reversed during Late Cretaceous. The interpretation of resistivity imaging logs allows identifying sedimentary structures, thicknesses, contacts hierarchies, paleocurrent directions and other details (e.g. bioturbation, intraclasts, root fragments and an inference of grain size). These data were compared with cutting samples and outcrops data in order to improve the sedimentological model for Bajo Barreal and Castillo Formations (Cretaceous). The integration of cutting samples (grain size and color) and resistivity imaging log allowed obtaining a stratigraphic log. Twelve sandstone bodies belonging to Bajo Barreal and Castillo Formations were analyzed following this method and ten litho-facies were defined from this study. The lithofacies assemblages were assigned to channel, crevasse channel, channel bar, splay and floodplain deposits. The sandstone bodies thickness (trough cross stratification) and paleocurrent directions were used to apply the Mackey and Bridge’s equation (1995) and obtain the channel belt width. The sandstone bodies were also associated with the SP and resistivity wire-logs to define a group of electro-facies. Finally, seismic horizon slices related to the sandstone bodies studied were also analyzed as intent to merge litho– and electro-facies assemblages and seismic geoforms. As paleocurrent directions coming from imaging log as seismic horizon slices are coincident in to point out several changes in the channel pattern and sinuosity. Most noticeable change occurs for those strata belonging to the lower section of Bajo Barreal Formation (informally named “tobácea section”). The sinuosity increases from 1.15 to around 2 and the channel belt wide reaches 500m. The sedimentary model of electro-facies may apply to wells (in the same or another oil field) without assistance of imaging log but with available 3D seismic information.