Uruguay Offshore New Frontier

Advanced data interpretation for underexplored continental margin

Map showing offshore Uruguay New Frontier multiclient survey area.

Uruguay’s continental margin is largely underexplored. However, its offshore basins have different tectonic and stratigraphic histories, which present diverse exploratory opportunities. The interesting geology, as well as the analogies with other South Atlantic basins, increase the basins’ exploratory potential. It has been recognized that a northeast depocenter migration took place following the Late Cretaceous period, and a number of structural, stratigraphic, and combined exploratory situations have been identified. Several direct and indirect hydrocarbon evidences do exist offshore Uruguay, including fluid inclusions of light oil and gas, oil seeps, gas chimneys, amplitude anomalies, AVO anomalies, velocity anomalies, and bottom-simulating reflectors.

The new high-quality seismic data is available to assist in reducing exploration risk for the upcoming licensing round. The clarity and scope of the new survey, complementing the legacy data, enables exploration companies to understand and properly evaluate the potential of the basin, including profile of the structure and identification of potential traps.

Advanced interpretation data package

Angle stacks
Seismic AVO attributes: gradient (G), intercept (P), product (P×G)
Reservoir characterization technology full-stack relative inversion: acoustic impedance (AI)
Horizons interpretation
Simultaneous AVO inversion: AI, Vp/Vs, density (RHO)

Basin potential unveiled

Using inversion of seismic amplitude data, seismic AVO attributes, AVO modeling, and well data integration techniques, our petrotechnical experts are able to estimate acoustic and elastic rock properties, that are related to reservoir properties including porosity, lithology, saturation, stress, and pore pressure. These results are used to screen or evaluate prospects, optimize borehole orientation, explain and predict well behavior, and populate static reservoir models.

Seismic data input—ANCAP UR 2011

58 lines with anisotropic Kirchhoff prestack depth migration (KPSDM)
6,293 km of 2D data

Well data input

Two wells in the southwest of the area with a complete set of logs

Full-stack simultaneous seismic inversion for AI

The simultaneous seismic inversion delivers a breakthrough in the analysis and interpretation of AVO seismic data. Partial stacks can be inverted directly for high-resolution acoustic impedance, Vp/Vs or shear impedance, and density. From these physical properties, lithology, fluid, and other rock properties may be predicted.

An analysis of AVO attributes from seismic gathers, plus attributes from AVO inversion, will permit a clearer identification of exploratory leads.