Step06 Forward Simulation

 

The data files for forward simulation are in: Geol_002b\Case03\06_Forward_sim\Data. Most of the files are identical to those in Case02 with the only difference being the extra stages for deposition of the eroded formation and its subsequent erosion included in the main data file and the corresponding displacement grid (.spat) files. It should be noted that the eroded formation does not have facies distribution obtained from restoration (as it is not explicitly modelled nor imported from Zmap) so that it can either:

 

1.Be assumed a single material/facies for the entire formation

2.Be assumed the same facies distribution as another formation (and hence the same facies grid may be assigned during its deposition)

3.The facies distribution grid may be defined manually

 

In the present case it is assumed that the eroded formation has the same facies distribution as the previous deposited formation (formation07). Below there is a description of the data within Geol_002b_Case03_fsim.dat file required to model the deposition and subsequent erosion of the eroded layer. The remaining data is not discussed here.

 

 

Forward simulation datafile

 

The present case comprises 12 stages with the sequence being as follows:

 

1.Geostatic stage with gravity initialisation and boundary displacements for creating the accommodation space between top surface and sedimentation horizon for deposition of formation02 (reversal of displacements during flattening of formation01 during restoration simulation)

2.Deposition of formation02 and boundary displacements to create the accommodation space for deposition of formation03

3.Deposition of formation03 and boundary displacements to create the accommodation space for deposition of formation04

4.Deposition of formation04 and boundary displacements to create the accommodation space for deposition of formation05

5.Deposition of formation05 and boundary displacements to create the accommodation space for deposition of formation06

6.Deposition of formation06 and boundary displacements to create the accommodation space for deposition of formation07

7.Deposition of formation07 and boundary displacements to create the accommodation space for deposition of the eroded formation

8.Deposition of the eroded formation and boundary displacements to expose the eroded formation above the sedimentation horizon (representing an erosion datum)

9.Removal/erosion of the eroded formation and boundary displacements to create the accommodation space for deposition of formation8

10.Deposition of formation08 and boundary displacements to create the accommodation space for deposition of formation09

11.Deposition of formation09 and boundary displacements to create the accommodation space for deposition of formation10

12.Deposition of formation10 and boundary displacements to create the present day topographic relief

 

Note that in all cases the sedimentation horizon corresponds to the flat restoration surface defined in Geol_002b_Case02_RestSurf01.dat file. Below a summary of the stage sequence and the key data for deposition and erosion of the eroded formation is discussed. Note that the remaining data will not be discussed here.

 

Data File

 

 

   (...)

 

! At the start of the stage formation07 is deposited and the accommodation space for the eroded formation is created

* Include

! ---------------------------------

 Filename   Geol_002b_Case02_rest_Disp_formation07.spat

 

* Control_data

! ---------------------------------

 Control_title             "formation07"

 

 

! At the start of the stage the eroded formation is deposited and the displacements expose such formation above the sedimentation horizon (representing an erosion datum)

* Include

! ---------------------------------

 Filename   Geol_002b_Case02_rest_Disp_Eroded_fm.spat

 

* Include

! ---------------------------------

 Filename   Geol_002b_Case02_rest_Fac_formation07.spat

 

* Sedimentation_data

! ---------------------------------

 Stratigraphy_unit_name           "eroded_fm"

 Duration                               12.0

 Spatial_grid_facies                    "Fac"

 

* Control_data

! ---------------------------------

 Control_title             "eroded_fm"

 

 

! At the start of the stage the eroded formation is removed/eroded and the accommodation space for formation08 is created. Note that the load corresponding to the eroded formation is ramped down over the duration of the stage following the assigned time curve.

* Include

! ---------------------------------

 Filename   Geol_002b_Case02_rest_Disp_Erosion.spat

 

* Deactivation_data

! ---------------------------------

 Group_names IDM=1

   "eroded_fm"

 Time_curve    "Step_scurve_down"

 

* Control_data

! ---------------------------------

 Control_title             "erosion"

 

 

! At the start of the stage formation08 is deposited and the accommodation space for the formation09 is created

* Include

! ---------------------------------

 Filename   Geol_002b_Case02_rest_Disp_formation08.spat

 

* Include

! ---------------------------------

 Filename   Geol_002b_Case02_rest_Fac_formation08.spat

 

* Sedimentation_data

! ---------------------------------

 Stratigraphy_unit_name         "formation08"

 Duration                               12.0

 Spatial_grid_facies                    "Fac"

 

* Control_data

! ---------------------------------

 Control_title             "formation08"

 

   (...)

 

•At the start of the stage named "formation07" such formation is deposited and the boundary displacements will create the accommodation space for deposition of the eroded formation (here named eroded_fm).

 

•At the start of the subsequent stage "eroded_fm" is deposited and the boundary displacements will expose such formation above the sedimentation horizon (which in this case may be considered as an erosion datum as well)

 

•At the beginning of the next stage the geometry/mesh for the "eroded_fm" is removed from the model by using the data structure Deactivation_data. The loads associated with the eroded formation are gradually ramped down over the duration of the stage according to the assigned time curve (in this case is an S-curve going from a load factor of 1 to a factor of 0 over the duration of the stage as indicated by "Step_scurve_down"). During the stage the boundary displacements will create the accommodation space between the top surface and the sedimentation horizon required for deposition of formation08.

 

 

 

 

Results

 

The results for the present workflow steps are provided in Geol_002b\Case03\06_Forward_sim\Results. Note that only a selection of the results is provided. In the figure bellow a detail of the modelled sequence for the eroded layer is shown. Thanks to the boundary conditions chosen during restoration, its derived displacements used to drive the boundary kinematics in the forward model we have been able to account for:

 

1.Generation of the accommodation space for deposition of the eroded formation

2.Uplift of the eroded formation so that it is exposed to erosion

3.Erode the formation and continue with the depositional sequence

 

 

Geol_002b_Case03_Fig06

 

Detail of the modelled sequence of deposition, uplift and erosion of the eroded layer. V.E. = 3