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A 3-dimensional deterministic dynamic basin model is constructed and applied to several sedimentary basins to determine the quantitative mass and energy transport in sedimentary sequences of a basin as a function of the geologic history. Input data consist of sedimentation rate and type, paleobathymetric estimates, initial physical (density, porosity, and permeability), and thermal (thermal conductivity and specific heat) properties of sediments, and heat flow. All the available data and know-how from geology, geophysics, geochemistry, strength of materials, hydrodynamics, and geothermics are combined in an integral form using the general physical, physicochemical, and chemical concepts as mathematical expressions. The results of the model are: geologic history and quanti ative stratigraphy, pressure history, thermal history, subsidence history, compaction history, porosity distribution, and organic matter maturation history.
The model results are then compared with the measured sediment thicknesses, pressures, temperatures, porosities, vitrinite reflectance values, and other geochemical maturity indicators. The model is calibrated, using a special iterative method based on sensitivity analysis. This method enables us not only to optimize the parameters of the system, but also to check the system for possible errors in the assumptions or in our understanding of the basin (conceptual model). Thus, each basin is analyzed as being a unique system.
Application of the model to several sedimentary basins has shown that high sedimentation rates increase pressures (mainly in shales) and temperatures, erosion decreases pressures (approach to hydrostatic) and temperatures, and thrusting generally decreases geothermal gradient. We have also found that generation of hydrocarbons can only be determined from heating rates using a kinetic model and not from simple generation vs. maturity trends (generation curve concept).
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