The use of finite element analysis on the characterization of the geometrical and temporal evolution of salt structures: the Matacães diapir case-study (Lusitanian basin, Portugal)

Abstract

This work presents the characterization of the geometrical and temporal evolution of the Matacães diapir, an outcropping salt structure located in the onshore of the Lusitanian Basin (Central Portugal), using the finite element analysis method (FEA).

The FEA method is a mathematical-based tool that aims to approximate reality through a model that is composed and solvable by the use of a finite number of variables. This type of analysis has a wide range of applications in oil geology, namely to recreate the paleogeography of a given area and to deduce the evolution of the geometric deformation of strata. By reproducing the forces that have acted on a certain area over time, the FEA is particularly important in modeling salt tectonics, as used in the present study of the Matacães diapir.

As the number of variables comprising the model increases, so does the correlation coefficient between the theoretical model and the observed reality. In the present work, the data used to create the model that represents the geometrical and temporal evolution of the Matacães diapir include: seismic cross-section, mechanical properties of the rocks, and stages of tectonic deformation and subsidence phases, recognized in specialized literature The resulting model in progress, is expected to represent, to a certain extent of associated error, the behavior of the salt structure, and the resulting driving influence on the migration of hydrocarbons inside the petroleum system. The model will also allow prediction of the geometric configuration of the sealing formation around the salt uplift structure, detailing the understanding of the migration pathways. Modeling with FEA method can also be a powerful tool to improve the understanding of subsurface data and resulting interpretation in hydrocarbon exploration.

AAPG Datapages/Search and Discovery Article #90226 © 2015 European Regional Conference and Exhibition, Lisbon, Portugal, May 18-19, 2015