Computer Modelling of Fluid Systems
Various computational tools are developed to facilitate complex thermodynamic modelling, including density and isochore estimations, primarily for fluid inclusion research. Additionally, these programs enable the experimental calculations of any p-T-V-x properties of pure gases and multicomponent fluid systems, supporting broader applications in phase equilibria and geochemical modelling.
Equations of state (eos) are adapted for fluid inclusion research to model phase behaviour and thermodynamic properties. These eos formulations facilitate the calculation of numerous thermodynamic parameters, including internal energy, enthalpy, entropy, Helmholtz energy, Gibbs energy, chemical potentials, heat capacity (CV, CP), viscosity, Joule-Thomson coefficient, speed of sound, spinodal curves and critical points. Such capabilities are essential for understanding fluid evolution, phase transitions, and geochemical processes in natural systems.
Bakker RJ (2023) The use of equations of state of pure components in pore fluid and fluid inclusion research: Computer program Pures (software package FLUIDS). Chemical Geology, vol. 640, 121751.
Gases (pure): H2O, CO2, CH4, N2, C2H6, O2, NH3, CO, D2O, H2 (normal, para, ortho), C3H8, SO2, H2S, Ar, He
Eos: Helmholtz energy functions
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Program: Pures, modification 01/2022
in progress
Program: Loner AP (april 2025)
Eos: Helmholtz energy function Anderko and Pitzer (1993a, b), Duan et al. (1995, 2003)
Components (mixtures and pure): H2O, CO2, CH4, NaCl, KCl
Program: Cubics (april 2025)
Eos: cubic equations of state (van der Waals, 1873; Redlich and Kwong (1949), Soave, 1972; Peng and Robinson, 1976) and modified-RK according to Chueh and Prausnitz (1967), Holloway (1977, 1981), Bakker (1999,2012)
Gases (mixtures and pure): H2O, CO2, N2, H2S, NH3, H2, O2, CO, Ar, CH4, C2H6, C3H8, iso-C4H10, n-C4H10, iso-C5H12, n-C5H12, iso-C6H14, n-C6H14, n-C7H16, n-C8H18, n-C9H20, n-C10H22
in progress
Bakker RJ (2019) Package Fluids. Part 5: The NaCl-H2O system in fluid inclusion research and applications of the software AqSo_NaCl (Bakker, 2018). Chemical Geology, vol. 525, 400-413.
Bakker RJ (2018) AqSo_NaCl: Computer program to calculate p-T-V-x properties in the H2O-NaCl fluid system applied to fluid inclusion research and pore fluid calculation. Computers and Geosciences, v. 115, 122-133.
Program: AqSo_NaCl, modification 02/2024
Eos: empirical additions (Driesner and Heinrich, 2007; Driesner, 2007) to pure H2O (Haar et al., 1984)
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Components (mixtures and pure): H2O, NaCl
Bakker RJ (2012) Thermodynamic properties and applications of modified van-der-Waals equations of state. In: Thermodynamics - Fundamentals and Its Application in Science, Ricardo Morales-Rodriguez (Ed.), 163-190.
Programs:
LonerW, mod. 10/2011
LonerRK, mod. 12/2011
LonerS, mod. 12/2011
LonerPR, mod. 10/2011
LonerCP, mod. 12/2011
LonerH, mod. 10/2011
Eos:
van der Waals (1873)
Redlich and Kwong (1949)
Soave (1972)
Peng and Robinson (1976)
Chueh and Prausnitz (1967)
Holloway (1977, 1981), Bakker (1999a)
Gases (mixtures and pure):
W: H2O, CO2, N2, H2S, NH3, H2, O2, CO, Ar, CH4
H : H2O, CO2, N2, H2S, NH3, H2, O2, CO, Ar, CH4, C2H6
RK, S: H2O, CO2, N2, H2S, NH3, H2, O2, CO, Ar, CH4, C2H6, C3H8, iso-C4H10, n-C4H10
B : NaCl, H2O, CO2, N2, H2S, NH3, H2, O2, CO, Ar, CH4, C2H6, C3H8, iso-C4H10, n-C4H10
PR, CP: H2O, CO2, N2, H2S, NH3, H2, O2, CO, Ar, CH4, C2H6, C3H8, iso-C4H10, n-C4H10, iso-C5H12, n-C5H12, n-C6H14, n-C7H16, n-C8H18, n-C9H20, n-C10H22
all included in “Cubics”
(see above)
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Bakker RJ (2012) Package FLUIDS. Part 4: Thermodynamic modelling and purely empirical equation of state for H2O-NaCl-KCl solutions. Mineralogy and Petrology, v. 105. 1-29.
Program: AqSo WHS, modification 04/2025
Eos: empirical equations, and thermodynamic modelling (liquidus, solvus)
Components (mixtures and pure): H2O, NaCl, KCl
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Bakker RJ (2009) Reequilibration of fluid inclusions: Bulk-diffusion. Lithos, vol.112, 277-288.
Program: ReqDif, modification 04/2025
Eos: 3D diffusion model of fluid inclusions
Components (mixtures and pure): H2O, CO2, CH4, NaCl
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Bakker RJ (2009) Package FLUIDS. Part 3. Correlations between equations of state, thermodynamics and fluid inclusions. Geofluids, vol. 9 (1), 63-74.
Program: LonerW, modification 04/2025
Eos: van der Waals (1873)
Gases (mixtures and pure): H2O, CO2, N2, H2S, NH3, H2, O2, CO, Ar, CH4
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Bakker RJ, Brown PE (2003) Computer modelling in fluid inclusion research. In: Fluid Inclusions, Analysis and Interpretation (eds. Samson I, Anderson A, Marshall D), Short Course v. 32, Mineralogical Association of Canada, 175-212
Bakker RJ (2003) Package FLUIDS 1. Computer programs for analysis of fluid inclusion data and for modelling bulk fluid properties. Chemical Geology, v. 194 , 3-23.
Programs: BULK, ISOC, modification 2003
Components (mixtures and pure): H2O, CO2, CH4, N2, C2H6, H2S, NH3, H2, O2, CO, NaCl, KCl, CaCl2, MgCl2
Bakker RJ (1999) Optimal interpretation of microthermometrical data from fluid inclusions: Thermodynamic modelling and computer programming. Habilitation Geology and Mineralogy, University Heidelberg, Germany.
Programs: Loner, AqSo, modification 2003
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package to calculate fluid inclusion properties and isochores
a variety of equations of state for gas mixtures and aqueous solutions
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Bakker RJ (1997) Clathrates: Computer programs to calculate fluid inclusion V-X properties using clathrate melting temperatures. Computers & Geosciences, v. 23, 1-18.
Bakker RJ, Dubessy J, Cathelineau M (1996) Improvements in clathrate modelling I: the H2O-CO2 system with various salts. Geochimica Cosmochimica Acta, v. 60, 1657-1681.
Bakker RJ (1998) Improvements in clathrate modelling II: The H2O-CO2-CH4-N2-C2H6 fluid system. In: Henriet, J.-P. & Mienert, J. (eds) Gas Hydrates: Relevance to World Margin Stability and Climat Change. Geological Society, London, Special Publications, v. 137, 75-105
Bakker RJ (1999) Optimal interpretation of microthermometrical data from fluid inclusions: Thermodynamic modelling and computer programming. Habilitation Geology and Mineralogy, University Heidelberg, Germany.
Programs: NOSALT, ICE, DENSITY, Q2, CURVES, modification 1998
Components (mixtures and pure): H2O, CO2, CH4, N2, C2H6, NaCl, KCl, CaCl2, MgCl2
Eos: Thermodynamic modelling of clathrate stabiity
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Bakker RJ, Jansen JBH (1993) Calculated fluid evolution path versus fluid inclusion data in the COHN system as exemplified by metamorphic rocks Rogaland SW Norway. Journal of Metamorphic Geology, v. 11, 426-440.
Program: FLEVOL, modification 1993
Eos: Mineral buffered fluid compositions in the C-O-H-N system
Bakker RJ (1992) On modifications of fluid inclusions in quartz, re-equilibration experiments and thermodynamical calculations on fluids in natural quartz. Geologica Ultraiectina, v. 94, 1-189.
Components (mixtures and pure): H2O, CO2, CH4, N2, NH3, H2, NO2, CO, O2
Eos: Purely empirical best-fit equations, designed at the Virginia Polytechnic Institute and State University (1988-2011)
Components: H2O, NaCl, KCl, CaCl2
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Program: AqSo VIR, modification 04/2025
Eos: Unified Helmholtz Energy functions of pure gases
Programs:
Loner HGK, mod. 05/2025
Loner SpW, mod. 05/2025
Loner SeW, mod. 05/2025
Gas:
H2O
CO2
CH4
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Eos: near-critical fluid properties of H2O (Levelt-Sengers et al., 1983)
Program: Loner LKBS, mod. 04/2025
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Bakker RJ (1999) Adaptation of the Bowers and Helgeson (1983) equation of state to the H2O-CO2-CH4-N2-NaCl system. Chemical Geology, vol. 154, 225-236.
Program:
LonerB, mod. 05/2025
Eos:
Bowers and Helgeson (1983), Bakker (1999b)
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gas mixture: H2O, CO2, N2, CH4, NaCl
also included: H2S, NH3, H2, O2, CO, Ar, C2H6, C3H8, iso-C4H10, n-C4H10
Bakker RJ, Thiery R (1994) Application of clathrates to fluid inclusion studies. In: De Vivo B, Frezzotti ML (eds) Short course of the working group (IMA) “Inclusions in minerals”. Pontignano - Sienna (Italy), 191 - 208.
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