Caprock integrity#

Evaluate pressure limits and identify regions where reservoir pressure exceeds the estimated caprock pressure limit.

The special variables limipres, overpres, and objepres support caprock-integrity analysis:

limipres: Estimated limiting pressure based on depth and the stress coefficient.
overpres: Difference between the simulated pressure and the estimated limiting pressure. Positive values identify cells where the pressure exceeds the estimated limit.
objepres: Objective value derived from the pressure-limit calculation. This quantity can be exported to CSV for use in optimization and sensitivity workflows.

The pressure-limit calculation uses the stress coefficient selected with plopm -sc.

Plot limiting and excess pressure#

Project the first 22 layers of the Norne model and compare limipres with overpres:

plopm -i NORNE_ATW2013 -s ',,1:22 ,,1:22' -v limipres,overpres -rot 65 -tr '[6456335.5,-3476500]' -x '[0,5600]' -y '[0,8800]' -fs 15,10 -c Spectral,spring -sg 1,2 -rdl 1

Limiting pressure and excess pressure across the first 22 layers of the Norne model — Limiting pressure and excess pressure projected across layers 1 through 22 of the Norne model.#

The command applies the same spatial selection to both quantities:

plopm -s selects layers 1 through 22.
plopm -rot rotates the Norne grid.
plopm -tr translates the rotated coordinates.
plopm -x and plopm -y crop the displayed region.
plopm -sg places both quantities in one row with two panels.
plopm -rdl removes repeated axis labels from the subplot layout.

Export the objective value#

Export objepres for the same layers as a CSV file:

plopm -i NORNE_ATW2013 -m csv -v objepres -s ',,1:22'

The CSV output can be used as an objective value in optimization, uncertainty quantification, and sensitivity studies.

Change the stress coefficient#

The default stress coefficient is 0.134. Select another value with plopm -sc:

plopm -i NORNE_ATW2013 -s ',,1:22 ,,1:22' -v limipres,overpres -sc 0.15 -rot 65 -tr '[6456335.5,-3476500]' -x '[0,5600]' -y '[0,8800]' -fs 15,10 -c Spectral,spring -sg 1,2 -rdl 1

Changing the stress coefficient changes the estimated limiting pressure and, consequently, the calculated excess-pressure and objective values.

Reproduce this example#

Run the complete workflow from the repository root:

. ./tests/scripts/docs_caprock_integrity.sh

View script

View raw script

Back to the examples gallery