--> Paleo-Fluid Flows and Present Hydrodynamic Conditions Improved by Basin Modeling Integrating Salinity Transport, Guichet, Xavier; Wolf, Sylvie; Pandi, Romuald, #90100 (2009)

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Paleo-Fluid Flows and Present Hydrodynamic Conditions Improved by Basin Modeling Integrating Salinity Transport

Guichet, Xavier1
 Wolf, Sylvie2
 Pandi, Romuald1

1Structural Geology, IFP, Rueil-Malmaison, France.
2
Applied Mathematics, IFP,
Rueil-Malmaison, France.

Basin models are currently used to reproduce the present-day observed pressures in basins by modeling coupled processes such sedimentation, compaction, heat-flow and fluid flow. Measured pressures are consequences of the geological history of the basins, and are related to an obvious estimate of the history of permeability fields. Permeability variations can be explained by geological, physical and chemical processes occurring in the course of the basin evolution. Moreover diagenetic phases have usually been associated with brine fluxes within basins.

The aim of our work is to calculate paleo-fluid flow which is then compared with fluid circulation assumptions proposed in geochemical studies to explain the main diagenesis stages identified in reservoirs. Therefore we developed a prototype for salinity transport based on Temis3D Software, which is a coupled numerical simulation program that evaluates pore pressure, porosity, overburden and other petroleum parameters through time. In our prototype, the salinity transport processes are calculated with an advection equation for a non-reactive solute such as salt. The heat and transport equations are coupled with the flow equation through the dependence of fluid density and of fluid viscosity on temperature and salinity. Equations are processed numerically by a finite-volume method on a square grid throughout the simulation of the basin evolution. For salinity transport, we require that groundwater along the halite bed maintain a salinity corresponding to saturation with respect to this mineral, and constant concentrations at surface are used distinguishing marine and continental environments. Finally the integration of salinity transport through the geological history of the basins permit to constrain the past evolution of a basin particularly in terms of palaeosalinity and palaeotemperature using fluid inclusion data. As basin models try to reproduce through geological time coupled phenomena, they are dedicated tools to distinguish likely patterns of paleo-fluid flow for diagenetic models.

A simulation of the 250Ma geological history of the
Paris basin, and a simulation of the 200Ma geological history of the North Louisiana Salt Basin will be presented and discussed.

AAPG Search and Discover Article #90100©2009 AAPG International Conference and Exhibition 15-18 November 2009, Rio de Janeiro, Brazil