Building fluids models

To use bluebonnet.fluids in a project:

import matplotlib.pyplot as plt
import numpy as np

from bluebonnet.fluids.fluid import Fluid
from bluebonnet.fluids.gas import (
    make_nonhydrocarbon_properties,
    pseudocritical_point_Sutton,
)

plt.style.use("ggplot")

Calculate formation volume factors

With the Fluid class, we estimate the reservoir fluid’s properties. That starts with formation volume factor and density. The pseudocritical point depends on the specific gravity and proportions of nitrogen, hydrogen sulfide, and CO_2_ present. Then, given a reservoir pressure and temperature, voila! b-factor!

fluid = Fluid(
    200, 35, 0.8, 650
)  # 200 degrees F, 35 degrees API, specific gas gravity: 0.8, 650 scf/bbl initial reservoir gor
non_hydrocarbon_properties = make_nonhydrocarbon_properties(
    0.05, 0.01, 0.04
)  # nitrogen, hydrogen_sulfide, co2
pseudocritical_point = pseudocritical_point_Sutton(
    0.8, non_hydrocarbon_properties, "wet gas"
)  # gas gravity
pressure = np.linspace(14.5, 5_000)
Bo = fluid.oil_FVF(pressure)
Bg = fluid.gas_FVF(pressure, *pseudocritical_point)
Bw = fluid.water_FVF(pressure)

fig, ax = plt.subplots()
ax.plot(pressure, Bo, label="Oil FVF", color="forestgreen")
ax.plot(pressure, Bg, label="Gas FVF", color="peru")
ax.plot(pressure, Bw, label="Water FVF", color="steelblue")
ax.legend(loc="center right")
ax.set(xlabel="Pressure (psi)", ylabel="b-factor", xlim=(0, None), ylim=(0, None));

Calculate viscosity

Viscosity and compressibility are the key pressure-varying diffusivity properties. Once again, these are available via the Fluid class.

fluid = Fluid(
    200, 35, 0.8, 650
)  # 200 degrees F, 35 degrees API, specific gas gravity: 0.8, 650 scf/bbl initial reservoir gor
non_hydrocarbon_properties = make_nonhydrocarbon_properties(
    0.05, 0.01, 0.04
)  # nitrogen, hydrogen_sulfide, co2
pseudocritical_point = pseudocritical_point_Sutton(
    0.8, non_hydrocarbon_properties, "wet gas"
)  # gas gravity
pressure = np.linspace(14.5, 5_000)
mu_o = fluid.oil_viscosity(pressure)
mu_g = fluid.gas_viscosity(pressure, *pseudocritical_point)
mu_w = fluid.water_viscosity(pressure)

fig, (ax1, ax2) = plt.subplots(2, 1)
ax1.plot(pressure, mu_o, label="Oil", color="forestgreen")
ax1.plot(pressure, mu_w, label="Water", color="steelblue")
ax2.plot(pressure, mu_g, label="Gas", color="peru")
ax1.legend(loc="upper right")
ax1.set(ylabel="Viscosity (cp)", xlim=(0, None), ylim=(0, None))
ax2.legend(loc="lower right")
ax2.set(
    xlabel="Pressure (psi)",
    ylabel="Viscosity (centipoise)",
    xlim=(0, None),
    ylim=(0, None),
);

Calculate compressibility

Compressibility is the last pressure-dependent factor important to single-phase flow.

from bluebonnet.fluids.gas import compressibility_DAK
from bluebonnet.fluids.oil import oil_compressibility_Standing
from bluebonnet.fluids.water import compressibility_water_McCain

c_g = [compressibility_DAK(200, p, *pseudocritical_point) for p in pressure]
c_o = [oil_compressibility_Standing(200, p, 35, 0.8, 800, *pseudocritical_point) for p in pressure]
c_w = compressibility_water_McCain(200, pressure, 0.0)

fig, ax = plt.subplots()
ax.plot(pressure, c_o, label="Oil", color="forestgreen")
ax.plot(pressure, c_w, label="Water", color="steelblue")
ax.plot(pressure, c_g, label="Gas", color="peru")

ax.legend(loc="upper right")
ax.set(
    xlabel="Pressure (psi)",
    ylabel="Compressibility (1/psi)",
    xlim=(0, None),
    yscale="log",
);