New Approach for Predicting Biodegradation in a Basin Modeling Perspective

Carpentier, Bernard¹, Françoise Behar¹, Henrique Luiz De Barros Penteado², François Lorant¹, Alain Y. Huc¹ (1) Institut Français du Pétrole, Rueil-Malmaison, France (2) Petrobras, Rio de Janeiro, Brazil

Predicting biodegradation risk is one of the major challenges for deep offshore explo­ration. Basin modeling, by reconstructing trap filling history is able to provide key informa­tion needed to anticipate the biodegradation level of a particular potential exploration target. In this paper we proposed a simplified new biodegradation modulus encapsulated within a petroleum system numerical model. Outputs of the basin model are used as boundary fac­tors in order to predict at regional scale the biodegradation level and then the quality of the oil present in the model cells where high petroleum saturation, suggesting accumulation occurrence, has been calculated. The proposed biodegradation prediction is based on depth, filling history and mass balance of initial and consumed carbon. The approach has been test­ed on a Brazilian series exhibiting a wide range of increasing biodegraded oil fields and where compositional quantitative data have been acquired. This paper will present the methodology of the approach and the application on a case study.