Step07 Forward Simulation
Contents
In the present tutorial page the key edits in the Geol_003_Case02_Step07_fsim.dat file (file edited for the present workflow step) relative to Geol_003_Case02_Step05_fsim.dat ("raw" file output in the previous step) required to run the simulation will be discussed in detail. Those comprise:
1.To define Facies_definition data in the first stage
2.To define Spatial_state_set data to assign the facies values from the spatial grid to the model mesh for the pre-existing units (encompassing formations 01 to 07)
3.To change the name of the Include file corresponding to the .spat file containing the initial facies distribution. Note that the name of such file could already had been correctly defined in Include_facies_files keyword within Util_set_material_data if the corresponding file name was known a priori.
The data files for forward simulation are provided in Geol_003\Case02\Step07_Fsim\Data. From those, the files carried from Case01 because they are identical are:
1.Geol_003_Case01_Step04_rest_Fac_formationN.spat files containing the spatial grids with the facies distribution for deposition of formationN (output from restoration).
2.Geol_003_Case01_Step06.mat file containing the material data for all the facies considered in the forward simulation.
3.Geol_003_Case01_Step06_geostatic.dat datafile with geostatic data on a facies basis including compaction trends for the different facies.
On the other hand, the files specific to the present case are:
1.Geol_003_Case02_Step05_fsim.geo initial geometry for the forward simulation
2.Geol_003_Case02_Step05_fsim_formationN.dat data file containing the part geometry definition used to drive the prescribed displacements for the stage in which formationN is deposited. The data files will be read by the main data file via Include data structure
3.Geol_003_Case02_Step05_fsim_formationN.sed data file containing the definition of the sedimentation horizon for formationN. The data files will be read by the main data file via Include data structure
4.Geol_003_Case02_Step07_fsim.dat main forward simulation data file. This is an edited version of the file output from the 5th workflow step.
5.Geol_003_Case02_Step06_gridout_Fac.spat containing the spatial grid distribution for the initial geometry of the forward simulation (which has been obtained in the previous workflow step).
The data in the forward simulation data file Geol_003_Case02_Step07_fsim.dat is identical to that of Case01 (Geol_003_Case01_Step06_fsim.dat) except that:
1.In the present case there is more data for the pre-existing formations (as there are 7 instead of only 1) regarding Geometry_set , Stratigraphy_definition , Stratigraphy_horizon and Group_data.
2.There are less simulation stages as in the present case the simulated history starts with deposition of formation08 as opposed to deposition of formation02 in Case01. Note that those stages comprise:
i.Two geostatic stages (initial Elastic initialisation followed by change to standard material models as defined in the .mat file)
ii.Three deposition and displacement stages for deposition of formations 08, 09 and 10.
The edits required in the forward simulation data file relative to the "raw" data file output from Restoration --> Forward conversion is discussed below.
Facies definition
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Results
The results for the forward simulation are provided in Geol_003\Case02\Step07_Fsim\Results. Note that only the results for the last plot file output are provided.
By loading the file Geol_003_Case02_Step07_fsim_041.xmf in ParaView the results within the plot (.plt) file can be visualised.
Comparison of final results from forward simulations in Case01 and Case02 (present case)
As can be seen in the figure, the results in this case are very similar to Case01 results. It should be noted however that this is because:
1.The model considered does not involve an important tectonic event 2.The simulations considered are mechanical only assuming hydrostatic pore pressures
Consequently the initial porosity distribution (NCT), the initial geostatic stresses (function of gravity and k values) and the hydrostatic pore pressure distribution assumed in the present case as the initial condition for formations 01 to 07 may be appropriate, and very close to the distributions predicted in Case01 at the equivalent time in basin's history. It is noted that in cases where tectonics may have an impact in compaction or when overpressure may have developed at times earlier than our chosen starting configuration, initial property distributions which honour the effect of such features may be difficult to obtain, often requiring a previous simulation of the "complete" basin history in order to obtain predictions that may be used to inform those initial distributions of the "partial" history models. Thus when we aim to run a forward simulation for the last few selected events we recommend to ask ourselves the following questions:
1.Are the selected events to be simulated going to capture the physics and processes we are interested in? 2.Are the (likely inaccurate) initial assumptions acceptable for our target application or are they going to significantly influence the results we are interested in?
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