Run a thermal model

A thermal run solves an energy equation beside the flow, so cells have a temperature that changes as hot or cold fluid moves through them. In PetroScript the heat model is one package in the model’s physics= list, ps.thermal.Package: the rock’s conductivity and heat capacity, the fluids’ heat capacities, and the initial temperature.

Here SPE1 (FIELD units) becomes a thermal run, its gas injector injecting at 80 degF:

import petroscript as ps

m = ps.load("opm-tests/spe1/SPE1CASE2.DATA")
heat = ps.thermal.Package(
    mode="thermal",                                   # or "temperature_only": see below
    rock=ps.thermal.RockProperties(conductivity=30.0, volumetric_heat_capacity=32.0),
    oil_heat_capacity=0.5, water_heat_capacity=1.0, gas_heat_capacity=0.25,
    initial_temperature=ps.initial.TemperatureVsDepth(depth=[8300.0, 8450.0],      # ft
                                                      temperature=[150.0, 200.0]),  # degF
)
hot = m.set("physics", [*m.physics, heat])
hot = hot.at(hot.start, ps.wells.InjectedStream(well="INJ", temperature=80.0))     # degF
deck = ps.compile(hot)
assert "THERMAL" in deck.files["SPE1CASE2.DATA"]

mode="thermal" writes THERMAL: Flow solves the energy equation together with the flow. mode="temperature_only" writes TEMP: Flow 2026.04 still solves an energy equation, but after each black-oil step rather than with it.

Every number is in the model’s units; ps.help(ps.thermal.Package) and ps.help(ps.thermal.RockProperties) name what each one is. A temperature is degF in FIELD and degC in METRIC (units).

What goes wrong:

• A package without the rock’s heat capacity or a conductivity is refused as it is built: thermal.rock.heat_capacity_missing, thermal.conductivity.missing. OPM Flow needs both in either mode.
• An injector with no injection temperature passes PetroScript’s checks, but OPM Flow stops in the pre-flight, and deck.run() raises ps.CompileError [preflight.refused] quoting it: Well INJ: Unable to obtain injection temperature - not specified in deck and no default defined. State ps.wells.InjectedStream(well=, temperature=) for every injector.

physics is a list: keep what a loaded deck already holds ([*m.physics, heat]) rather than replacing it. The fluids’ heat capacities can also be tables against temperature (ps.thermal.FluidHeatCapacity), and the densities and viscosities can vary with temperature (ps.thermal.DensityVsTemperature, ps.thermal.ViscosityVsTemperature).