--> Abstract: Abstract: Integration of a Crustal Stretching Model into the Workflow of Basal Heat Flow Calibration, by Thomas Fuchs, Christian Zwach, Armin Kauerauf, Thomas Hantschel, nd Jakob Skogseid; #90066 (2007)
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Integration of a Crustal Stretching Model into the Workflow of Basal Heat Previous HitFlowNext Hit Calibration

Thomas Fuchs1, Christian Zwach2, Armin Kauerauf1, Thomas Hantschel1, and Jakob Skogseid2
1IES, Integrated Exploration Systems, Ritterstr. 23, 52072 Aachen, Germany
2 Hydro Oil and Energy, Global Exploration, Drammensveien 264, N-0240 Oslo, Norway

The basal heat Previous HitflowNext Hit is the most important quantity Previous HitdeterminingNext Hit the thermal evolution within a sedimentary basin. Commonly, it is calculated by inversion from vitrinite reflectance and temperature data for a basin model. Unfortunately, this procedure does only cover the younger geologic history of the earth. However, heat Previous HitflowNext Hit can be estimated through knowledge of stretching time and factors in rift basins for paleo times. If the type of rifting and its timing is known, it is possible to calculate the stretching factors by inversion of subsidence from the basin model. Heat Previous HitflowNext Hit calibration can thus be subdivided into two parts. Firstly, an overall heat Previous HitflowNext Hit is calculated by crustal modeling and secondly it is calibrated against well data. An integrated workflow with a consistent and efficient employment of these steps is demonstrated for a case study. The details are given by the following specifications:

A discontinuous, pure shear stretching model which contains two different stretching factors for crust and mantle is used. Heat produced in the crust by radioactivity is taken into account. The stretching factors are fitted to the tectonic subsidence of the basin model, which is extracted by stratigraphic backstripping. According to the ductile Previous HitnatureNext Hit of the mantle the resulting stretching factor maps are smoothed afterwards. Finally, heat Previous HitflowNext Hit maps through time are created from the stretching model. The quality of the fit can be quantified.

In order to achieve calibrated heat Previous HitflowNext Hit maps it is necessary to adapt the heat Previous HitflowNext Hit so that the model matches vitrinite reflectance and temperature data. Small areas of interest around the wells, which are big enough to include lateral temperature effects, can be modeled fast with varying heat Previous HitflowNext Hit in full 3D. The heat Previous HitflowNext Hit can accurately be determined with an inversion based on interpolated model runs. In the regions between the wells the heat Previous HitflowTop is interpolated. A significant shortcut of the workflow can be achieved by simulating all areas of interest together in one model.

We demonstrate the new integrated workflow on an exploration case study and show the advantages of application of a crustal stretching model.

 

AAPG Search and Discover Article #90066©2007 AAPG Hedberg Conference, The Hague, The Netherlands

 

AAPG Search and Discover Article #90066©2007 AAPG Hedberg Conference, The Hague, The Netherlands