3-D Stratigraphic Modeling in Complex Tectonics Area at an Exploration to Reservoir Scale

Didier Granjeon, Sylvie Wolf, Simon Lopez, and Tristan Salles
Institut Français du Pétrole, Rueil Malmaison, France

Thanks to the recent developments in numerical modelling, relationship between tectonics and sedimentation can be investigated from source to sink using coupled stratigraphic and structural numerical models both at exploration and reservoir scales. This paper is focused on the use and link of such deterministic numerical models.

In a first step, a forward stratigraphic and structural simulation is performed at a large scale to study the regional evolution of the sedimentary system. This simulation is performed from the past up to the present, and at each time step, three main geological "processes" interacts : (1) creation of accommodation by eustasy and a complex tectonic deformation of the basin due to growth faults and salt diapirs, (2) sediment supply brought into or produced in situ, and (3) long-term sediment transport. In a second step, a reservoir-scale deterministic model is used to better describe the local sedimentary processes, and get a better characterisation of the reservoir heterogeneities, constrained by the regional simulation.

These coupled basin to reservoir scale, stratigraphic and structural simulations, are illustrated with an application on the Niger Delta, where growth faults and sedimentary processes interact, and control reservoir and seal properties, but also overpressure. This application shows us that this link between stratigraphic forward models at different scales is a dreamed key to decipher the stratigraphic records in synkinematic series and better understand the source to sink systems, although great scientific effort still have to be put on their developments to close the process-deposit loop in complex tectonic settings.