Sensitivity and Risk Analysis in 2D Petroleum System Study - A Case Study from the Jequitinhonha Basin, Offshore Brazil

Abstract

A 2D petroleum system analysis was undertaken to evaluate a consistent scenario for understanding the petroleum system behaviour in the Jequitinhonha Basin, offshore Brazil. The 2-D section is a seismic line from a 3-D seismic survey, where prospects were recognized, but no well was drilled along the section and well data are poor. But in this part of the Jequitinhonha Basin, the migration pattern, migration pathways and related drainage systems are complex and 3D phenomena, strongly controlled by the presence of salt and salt movements. The effect of different parameters and/or geological phenomena on the petroleum system behaviour could not be estimated quantitatively. Therefore a sensitivity and risk analysis was performed. The results of the sensitivity analysis allowed determining the sensitive parameters for the hydrocarbon saturation in the prospective areas and led additionally to new results for the petroleum system behaviour, their impact on migration and present day accumulations in this area. Based on these results different scenarios controlling the system for the petroleum system were tested and evaluated. The estimation of the risk on hydrocarbon charge and trap potential, according to the uncertainties on the petroleum system components could be established.