An Application of High Resolution of Sequence Stratigraphy: Implications for Improved Description, Modeling and Management of the Springhill and Magallanes Reservoirs, Austral Basin, Argentina

Morgan Sullivan¹, Marcelo Juan Cagnolatti², Jorge Gustavo Arguello², Fabian Edgardo Gutierrez², Alejandro Gustavo Trapiche², Lius Lucas Saccavino², Sergio Roberto Falconaro², and Carlos Echevarría^2
1 California State University, Chico, CA
² Petrobras Energía SA, Neuquén, Argentina

The continental portion of the Austral Basin is located in southern Argentina and has been producing hydrocarbons for over 60 years. In order to evaluate remaining hydrocarbon potential in this prolific basin, an integrated sequence stratigraphic study of the Lower Cretaceous Springhill reservoir and the Maastrichtian to Paleocene Magallanes reservoir was conducted to increase the understanding of reservoir distribution and to provide new predictive models for optimizing reservoir producibility and near-field exploration.

The depositional and stratigraphic models for both reservoirs have been significantly modified. Both formations were originally interpreted as conformable beach/shoreface deposits which prograded from east to west. Based on this study, however, these reservoirs, are re-interpreted as stacked unconformity bounded, north-south trending incised valley deposits. The recognition that the distribution of both reservoirs is strongly controlled by erosion and that they are sub-unconformity plays has also improved prediction of reservoir continuity and distribution.

In summary, the advantage of having this integrated sequence stratigraphic reservoir model can be basically broken down into 2 aspects. Firstly, in terms of Reservoir Management this new sequence stratigraphic framework has led to optimization of development plans, new production and development opportunities, and reduced uncertainty for reserves certification. Secondly this integration has also impacted Project Management by combining geologists, geophysists and engineers into integrated teams for semi-regional and field scale studies in order to allow sharing of concepts and ideas which has improved significantly communications and decisions making.

AAPG Search and Discovery Article #90039©2005 AAPG Calgary, Alberta, June 16-19, 2005