Add an aquifer

An aquifer is water outside the grid that pushes into it as the reservoir pressure falls. In PetroScript it is one object in the model’s aquifers= list: the aquifer’s own properties, and the grid faces it flows in through (ps.aquifers.Connection).

Aquifer	Class	What you state
Finite, pseudo-steady (Fetkovich)	ps.aquifers.Fetkovich	its water volume, total compressibility and productivity index
Infinite-acting, radial (Carter-Tracy)	ps.aquifers.CarterTracy	its permeability, porosity, compressibility, radius, thickness and angle
A set influx	ps.aquifers.ConstantFlux, then ps.aquifers.Flux at a date	the water rate per unit area of the connected faces (not a total)
Grid cells of its own	ps.aquifers.Numerical	its cells

Here a Fetkovich aquifer goes under SPE1 (a FIELD deck: ft, psia, stb), connected to the bottom face of the bottom layer:

import petroscript as ps

m = ps.load("opm-tests/spe1/SPE1CASE2.DATA")
bottom = ps.aquifers.Connection(cells=ps.Box(i=(1, 10), j=(1, 10), k=(3, 3)),  # all three ranges
                                face="plus_k")                                 # their lower face
support = ps.aquifers.Fetkovich(
    datum_depth=8450.0,                    # ft
    initial_water_volume=2.0e9,            # stb
    compressibility=6.0e-6,                # 1/psi: water and rock together
    productivity_index=200.0,              # stb/day/psi
    connections=[bottom],
)
with_aquifer = m.set("aquifers", [support])
deck = ps.compile(with_aquifer).files["SPE1CASE2.DATA"]
assert "AQUFETP" in deck and "AQUANCON" in deck

A connection’s box states all three ranges ([aquifers.connection.cells] otherwise). The datum pressure, left out, is the reservoir’s at the aquifer’s datum depth, so the aquifer starts in equilibrium with it. A Carter-Tracy aquifer takes rock properties instead:

radial = ps.aquifers.CarterTracy(
    number=2, datum_depth=8450.0, permeability=200.0, porosity=0.25,
    total_compressibility=6.0e-6, radius=5000.0, thickness=100.0,   # ft
    angle=360.0,                                                    # degrees: all round
    connections=[bottom],
)

To see what the aquifer is worth, run the model with and without it: m.set("aquifers", []) removes every aquifer. examples/aquifer.py does exactly that in Flow and prints both pressure declines.

ps.help(ps.aquifers.Fetkovich) and ps.help(ps.aquifers.Connection) have every field.