Calculation of gas density

Gas density is calculated using real gas equations from input pressure, temperature and specific gravity of gas. The compressibility factor is calculated explicitly (Beggs and Brill - 1973) for the pressure and temperature combinations. The plot shows the variation of the gas density for methane gas (SG = 0.55) with varying temperature and pressure.

from pathlib import Path

import matplotlib.pyplot as plt
import pandas as pd

from indsl.oil_and_gas.gas_density_calcs import calculate_gas_density as cd


# pressure and temperature series define
base_path = Path(__file__).parents[2] if "__file__" in globals() else next(p for p in (Path.cwd(), *Path.cwd().parents) if (p / "datasets").exists())
data = pd.read_csv(base_path / "datasets" / "data" / "density_pr_tmp.csv", index_col=0)
sg = pd.Series([0.5534])
fig, ax = plt.subplots(1, 2, figsize=[10, 5])

ax[0].plot(
    data["T_var (F)"],
    cd(data["P_con (psi)"], data["T_var (F)"], sg),
    color="blue",
    linestyle="dashed",
    linewidth=1,
    markersize=10,
    marker=".",
    label="Gas density at " + str(data.at[data.index[0], "P_con (psi)"]) + " psi",
)

ax[0].set_xlabel("Temperature (deg F)")
ax[0].set_ylabel("Gas Density (pcf)")
ax[0].legend()


ax[1].plot(
    data["P_var (psi)"],
    cd(data["P_var (psi)"], data["T_con (F)"], sg),
    color="blue",
    linestyle="dashed",
    linewidth=1,
    markersize=10,
    marker=".",
    label="Gas density at " + str(data.at[data.index[0], "T_con (F)"]) + " deg F",
)
ax[1].set_xlabel("Pressure (psi)")
ax[1].legend()

plt.show()