rockphypy.BW

Batzle and Wang functionalities

Module Contents

Classes

BW	Effective CO2, natural gas, brine and oil property calculation using original and modified Batzle-Wang equations.

class rockphypy.BW.BW

Effective CO2, natural gas, brine and oil property calculation using original and modified Batzle-Wang equations.

static dz_dp(P_pr, T_pr)

Values for dZ/dPpr obtained from equation 10b in Batzle and Wang (1992).

static pseudo_p_t(P, T, G)

Calculate the pseudoreduced temperature and pressure according to Thomas et al. 1970.

Parameters:

• P (float or array-like) – Pressure in MPa

• T (float or array-like) – Temperature in °C

• G (float) – Gas gravity

Returns:

float or array-like – Ta: absolute temperature Ppr:pseudoreduced pressure Tpr:pseudoreduced temperature

static rho_K_co2(P, T, G)

Compute CO2 properties as a function of temperature and pressure using modified Batzle-Wang equations

Parameters:

• P (float or array-like) – Pressure in MPa

• T (float or array-like) – Temperature in °C

• G (float) – Gas gravity

Returns:

float or array-like – rho (g/cc): gas density K (GPa): bulk modulus

References

Xu, H. (2006). Calculation of CO2 acoustic properties using Batzle-Wang equations. Geophysics, 71(2), F21-F23.

static rho_K_gas(P, T, G)

Estimate the Gas density and bulk modulus at specific temperature and pressure.

Parameters:

• P (float or array-like) – Pressure in MPa

• T (float or array-like) – Temperature in °C

• G (float) – Gas gravity

Returns:

float or array-like – rho: Gas density (g/cm3) K: Gas bulk modulus (GPa)

static rho_K_oil(P, T, den)

Estimate the oil density and bulk modulus at specific temperature and pressure.

Parameters:

• P (float or array-like) – Pressure in MPa

• T (float or array-like) – Temperature in °C

• den (float) – oil density in g/cm3

Returns:

float or array-like – rho: oil density (g/cm3) K: oil bulk modulus (GPa)

static rho_K_go(P, T, den, G, Rg)

compute density and bulk modulus of live oil.

Parameters:

• P (float or array-like) – Pressure in MPa

• T (float or array-like) – Temperature in °C

• den (float) – oil density in g/cm3

• G (float) – gas gravity

• Rg (float) – the volume ratio of liberated gas to remaining oil at atmospheric pressure and 15.6°C, Liter/Liter

Returns:

float or array-like – rho_g (g/cm3): true density of live oil at saturation K (GPa): true bulk modulus of live oil at saturation

static rho_K_water(T, P)

Compute the density and bulk modulus of pure water as a function of temperature and pressure using Batzle and Wang (1992).

Parameters:

• T (float or array-like) – Temperature in °C

• P (float or array-like) – Pressure in MPa

Returns:

float or array-like – rho_w (g/cm3): density of pure water K_w (Gpa): bulk modulus of pure water

static v_water(T, P)

Acoustic velocity of pure water as a function of temperature and pressure using Batzle and Wang (1992).

Parameters:

• T (float or array-like) – Temperature in °C

• P (float or array-like) – Pressure in MPa

Returns:

float or array-like – v_w (m/s): acoustic velocity of pure water

static rho_K_brine(T, P, S)

Calculation of the density and bulk modulus of brine (NaCl) as a function of temperature, salinity and pressure using Batzle and Wang (1992).

Parameters:

• T (float or array-like) – Temperature in °C

• P (float or array-like) – Pressure in MPa

• S (float) – weight fraction of sodium chloride in ppm/1e6

Returns:

float or array-like – rho_b (g/cm3): the density of brine K_b (GPa):bulk modulus of brine

static v_brine(T, P, S)

Calculte the acoustic velocity of brine as a function of temperature, salinity and pressure using Batzle and Wang (1992).

Parameters:

• T (float or array-like) – Temperature in °C

• P (float or array-like) – Pressure in MPa

• S (float) – weight fraction of sodium chloride in ppm/1e6

Returns:

float or array-like – v_b (m/s): the velocity of brine

static co2_brine(temperature, pressure, salinity, Sco2, brie_component=None, bw=False)

compute the effective properties of critical Co2 brine mixture depending on temperature, pressure and salinity of the brine, as well as the saturation state.

Parameters:

• temperature (degree) –

• pressure (Mpa) – pore pressure, not effective stress

• salinity (ppm) – The weight fraction of NaCl, e.g. 35e-3 for 35 parts per thousand, or 3.5% (the salinity of seawater).

• Sco2 (frac) – Co2 saturation

• brie_component (num) – if None: uniform saturation. otherwise patchy saturation according to brie mixing

Returns:

den_mix (g/cc) – mixture density Kf_mix (GPa): bulk modulus