Model of the circulatlon of meteorlc water in basins of the brazilfan continental margin

Abstract

Biodegraded oils are found in basins of Brazilian continental margin even at great distances from the present coast and at great depths. Since this phenomenon is of substantial relevance for exploration purposes, a model of the hydrodynamic circulation of meteoric water in these basins was designed and tested. According to the model, meteoric water transported both the bacteria responsible for degrading the petroleum as well as the oxygen and nutrients needed by these organisms. Infiltration of the water look place during sea-level lowstands, especially in the Pleistocene. The model was proved through ionic and isotopic analyses of water recovered during drillstem and production tests.