GRAV_SUBS_POINTS

Modelling gravity change and subsidence based on flow simulation output (EGRID, INIT and UNRST files) for a list of locations ( bencmark stations) at seabed.

The script reads flow simulation results and a yaml configuration file specifying input and calculation parameters. For configuration of the yaml config file, see: https://fmu-docs.equinor.com/docs/subscript/scripts/grav_subs_points.html

usage: grav_subs_points [-h] -c CONFIGFILE [-o OUTPUTDIR]
                        [--prefix_gendata PREFIX_GENDATA]
                        [--extension_gendata EXTENSION_GENDATA] [--version]
                        UNRSTfile

Positional Arguments

UNRSTfile

Path to flowsimulator UNRST file

Named Arguments

-c, -C, --configfile

Name of YAML config file

-o, --outputdir

Path to directory for output files. Directory must exist.

Default: “./”

--prefix_gendata

File prefix used for output files for GEN_DATA,

Default: “”

--extension_gendata

File extension used for output files for GEN_DATA,including report step number

Default: “.txt”

--version

show program’s version number and exit

# Example config file for grav_subs_points

input:
  diffdates: # List of difference dates to model. Dates must exist in UNRST file.
    - [2020-07-01, 2018-01-01]

stations: # Path to files with station coordinates to model for each diffdate (years)
  grav:
    "2020_2018": station_coordinates.csv
  subs:
    "2020_2018": station_coordinates.csv

calculations:
  poisson_ratio: 0.45 # For subsidence calulcations, used in Geertsma model
  phases: ["gas", "oil","water", "total"] # One pointset for each phase specified

Include dates

Instead of specifying the modelling dates directly in the yaml config file it is possible to include them from another yaml file:

input:
  diffdates: !include_from global_variables.yml::global.dates.GRAVITY_DIFFDATES

This is an advantage if the dates in the global config is used also for other jobs. In this example the included file looks like this:

# example global config file with dates
global:
  dates:
    GRAVITY_DIFFDATES:
    - - 2020-07-01
      - 2018-01-01

Station coordinates

The file with station coordinates should be on .csv format and contain headers as specified in this example:

bm_id;utmx;utmy;depth;area
1;462632.692871;5930050.419434;200.000000;WL
2;464438.063965;5932652.277710;200.000000;CH
3;462924.737793;5933448.764526;200.000000;CH
4;459977.734863;5935121.387695;200.000000;NH
5;462247.045000;5934298.281000;200.000000;CH
6;461517.610352;5933448.764526;200.000000;CN
7;463933.621582;5931643.393677;200.000000;CS
8a;463429.180176;5935068.288086;200.000000;EL
9b;460561.825684;5936608.163086;200.000000;CH
10;460482.177246;5931723.042358;200.000000;WL
bm_id: Name of the bencmark location.
utmx: UTM X for the bencmark location [m]
utmy: UTM Y for the bencmark location [m]
depth: Seabed depth for benchmark location [m TVD MSL]
area: An area identifier that can be used for grouping or labeling in visualisations

The output files

There will be two types of output file from grav_subs_points.

  • one column text files of modelled gravity change/subsidence GEN_DATA files that can be used with ert GENERAL_OBSERVATION

  • x,y,z text file that can be used for visualisation.

The ordering of points in these two files will be the same as given in the station coordinates file used as input. It can therefore be a good idea to order the benchmark stations in the station coordinates file in the order you would like to see them in e.g. line plots, for instance sorted by area.

In some cases where the reservoir model covers several structures or fields it can be beneficial to split the modelling for different structures into several files. E.g. for testing in assisted history matching what effect it has if only observations for one of the structures is used as observations compared to both. To facilitate this usage the option to add a prefix to the GEN_DATA file to separate them, using the prefix_gendata option. There is also a possibility to use a different report step and extension than the default “.txt” by using the extension_gendata option. The default is now without any report step, since this is now longer needed in ert. But if defining a report step is needed, an extension like e.g. “_10.txt” could be given.