Step06 Forward Simulation

Contents

The present workflow step demonstrates the usage of facies during forward simulation. In the same manner as in restoration, Facies_definition is required to assign Material_data to facies ID numbers. Then a Spatial_grid at each deposition stage is used to define the facies distribution for the deposited formation and Geostatic_data defines the initial depositional porosity distribution with depth.

The data files for forward simulation are provided in Geol_002b\Case02\06_Forward_Sim\Data. Those files are:

1.Geol_002b_Case02_fsim.dat main datafile for the forward simulation.

2.Geol_002b_Case02_rest_formation01.geo initial geometry (last geometry file obtained from restoration)

3.Geol_002b_Case02_fsim_geostatic.dat datafile with geostatic data on a facies basis including compaction trends for the different facies.

4.Geol_002b_Case02_RestSurf01.dat file with the sedimentation surface (restoration surface in restoration)

5.Geol_002b_Ss_Si_Sh_Ca.mat file containing the material data for the forward simulation

6.Geol_002b_Case02_fsim_sides.dat datafile containing the geometry sets for the side boundaries

7.Geol_002b_Case02_rest_Disp_formationNN.spat files containing the spatial grids (output from restoration) with the boundary displacements for all stages where NN is the formation number being deposited on such stage.

8.Geol_002b_Case02_rest_Fac_formationNN.spat files containing the spatial grids with the facies distribution for formationNN (output from restoration).

Facies definition

Data File

* Facies_definition

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

Facies_names IDM=4

"Mech_100_00_00_00"

"Mech_80_00_20_00"

"Mech_20_00_80_00"

"Mech_00_00_100_00"

Facies_ids IDM=4

1 2 3 4

* Include

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

Filename Geol_002b_Case02_rest_Fac_formation01.spat

* Spatial_state_set NUM=1

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

Spatial_grid "Fac"

Groups IDM=1

"formation01"

State_variables IDM=1

"Facies"

•Facies_definition is specified to assign a Material_data to each Facies ID number

•The Spatial_grid with the initial facies distribution (for the initial formation) is within the .spat file for formation01 output from restoration and is loaded via the data structure Include

•Spatial_state_set is used to set the initial facies distribution in formation01 using the Spatial_grid "Fac"

Sedimentation

At each sedimentation stage, in order to define the facies distribution for the deposited unit it is required:

1.Definition of the Spatial_grid_facies keyword within Sedimentation_data, which defines the name of the facies distribution spatial grid

2.Definition of the assigned Geostatic_data on a facies basis. It is expected that this data will be identical for all sedimentation stages.

Data File

! Data defined once

* Sedimentation_parameters

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

Sediment_horizon_name "Sed"

Minimum_thickness 40

Sedimentation_type "Structure"

Thermal_advection_flag 0

* Include

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

Filename Geol_002b_Case02_RestSurf01.dat

* Sedimentation_horizon NUM=1

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

Name "Sed"

Type "Facet"

Geometry_part "Restoration_surface"

! Data defined at each sedimentation stage

* Include

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

Filename Geol_002b_Case02_rest_Fac_formation02.spat

* Sedimentation_data

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

Stratigraphy_unit_name "formation02"

Duration 12.0

Material_name "Mech_00_00_100_00"

Geostatic_set_name "Sedimentation"

Num_struct_divisions 3

Kerogen_assignment "kerogen1"

Spatial_grid_facies "Fac"

* Include

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

Filename Geol_002b_Case02_fsim_geostatic.dat

•Sedimentation_parameters, Sedimentation_horizon as well as the included part geometry data defining the sedimentation surface are identical than those in Case01 but are included here to facilitate quick reference.

•Data structure Include is used to read the file containing the Spatial_grid with the facies ID number distribution for the deposited unit "formation02" (file output from restoration)

•In Sedimentation_data the keyword Spatial_grid_facies is used to define the name of the spatial grid used to assign facies distribution to the deposited unit.

•Data structure Include is used to read the file containing the Geostatic_data defined on a facies basis to be assigned to the deposited unit (with different porosity vs. depth curves for each facies). Note that all the facies are defined with the same initial kx and ky values for calculating the initial horizontal stresses (limitation at present) but after termination of deposition the horizontal stresses for each facies will evolve according to its corresponding material properties.

Results

The results for the forward simulation are provided in Geol_002b\Case02\06_Forward_simulation\Results. Note that only a selection of results are provided.

By loading the file Geol_002b_Case02_fsim.xmf in ParaView the full series of output plot files (.plt files) can be visualised (in this case the ones provided).

In the figures below comparison of facies and porosity distribution at the end of deposition of formation08 (time 96) is compared to its corresponding state in restoration (end of flattening of formation09). Note that small differences in facies distribution are observed which are attributed to the small deviation in cell locations between restoration and forward simulation leading to different facies ID assignment from the mapping for some cells. The differences in porosity are attributed to the different assumptions between restoration and forward simulation (e.g. in restoration materials are elastic and decompact following the normal compaction trend, whereas in forward simulation the materials are plastic and overpressure may develop leading to undercompaction).

Geol_002b_Case02_Fig05

Comparison of facies and porosity distribution between forward simulation at the end of deposition of formation08 and corresponding state in restoration (end of flattening of formation09)