Present-day hydrodynamic conditions

The type of sedimentary basin and its history of subsidence, heat flow and deformation are the main factors that determine the present-day hydrodynamic conditions in a basin. In the qualitative approach, the identification of the hydrodynamic conditions in present-day stable subaerial basins is restricted to the identification of the gravity-induced groundwater flow conditions. The identification of hydrodynamic conditions in sedimentary basins which are in whole or in part below sea level, should be based on the presupposition that both subsidence of and sedimentation in the basin as well as gravity-induced flow from continental areas surrounding the subaquatic part of the basin may have induced the present-day hydrodynamic conditions. In addition the potential influence of recent tectonic and/or magmatic activity should be taken into account. 

The application of the above-mentioned modelling techniques allow the assessment of the relative importance of the possible pressure generating mechanisms and the different characteristics of the hydrogeological framework in relation to the observed present-day hydrodynamic conditions in the basin. 

A quantitative analysis of present-day secondary hydrocarbon migration for basin evaluation can be restricted to the prospective parts of a sedimentaiy basin as selected on the basis of the previously described qualitative study (Chapter 7). The quantitative assessment of present-day hydrocarbon migration systems is described separately for hydrostatic and hydrodynamic conditions of the prospective parts of the basin (Sections 8.1, 8.2 and 8.3). Section 8.4 briefly describes the available approaches for a quantitative analysis of the evolution of secondary hydrocarbon migration systems. 

The present-day burial-induced hydrodynamic conditions in the selected area can be assessed directly from the groundwater pressure, density and viscosity data and the permeability data. 

Hydrodynamic conditions in a basin may in part result from tectonic forces. Ge and Garven (1989) applied a numerical model of coupled tectonic- and gravity-induced flow to evaluate the relative importance of tectonic influence on groundwater pressure and flow in an otherwise gravity-induced flow system in a hypothetical foreland basin. Forbes et al. (1992) included an evaluation of lateral compression in their numerical reconstruction of the present-day pressure distribution in the Venture Field, Eastern Canada. 

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