Phase equilibria modeling applied to fluid inclusions: Liquid-vapor equilibria and calculation of the molar volume in the CO[sub 2]-CH[sub 4]-N[sub 2] system

Journal Article · Tue Feb 01 00:00:00 EST 1994 · Geochimica et Cosmochimica Acta; (United States)

DOI:https://doi.org/10.1016/0016-7037(94)90573-8· OSTI ID:7164911

Thiery, R; Dubessy, J ^[1]; Vidal, J ^[2]

---

1. Centre de Recherche sur la Geologie des Matieres Minerales et Energetiques, Vandoeuvre-les-Nancy (France)
2. Laboratoire de thermodynamique, Rueil Malmaison (France)

Quantitative use of fluid inclusions requires the determination of composition and molar volume. The molar volume can be calculated in the CO[sub 2]-CH[sub 4]N[sub 2] system from both the determination of the temperature of a L + V [yields] L (or V) equilibrium if the composition is known independently, provided an equation of state (EOS) reproduces the P-V-T-X properties of each phase at equilibrium. This study is applicable to fluids for which the sequence of phase transition is S[sub CO2] + L + V [yields] L + V [yields] L (or V) at increasing temperature. The molar volume is determined by following a two-step algorithm: (1) the pressure is calculated from a two-parameter cubic EOS with interaction parameters optimized along experimental L-V isotherms (2) the molar volume is then calculated by the correlation of LEE and KESLER (1975) with the pressure calculated in the first step. Projections of polybaric L-V isotherms in [upsilon]-X diagrams of the CO[sub 2]-CH[sub 4], CO[sub 2]-N[sub 2], and CH[sub 4]-N[sub 2] systems can be directly applied to fluid inclusion studies. In addition, it is shown that the molar volume of CO[sub 2]-rich fluids (X[sub CO2] > 0.6) in the ternary system can be estimated with sufficient accuracy using empirical formulae relating to the [upsilon]-X diagrams of the CO[sub 2]-CH[sub 4] and CO[sub 2]-N[sub 2] binary systems.

• OSTI ID: 7164911
• Journal Information: Geochimica et Cosmochimica Acta; (United States), Vol. 58:3; ISSN 0016-7037
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
03 NATURAL GAS
02 PETROLEUM
CARBON DIOXIDE
EQUILIBRIUM
MIXING
PHASE TRANSFORMATIONS
METHANE
NITROGEN
COMPUTERIZED SIMULATION
INCLUSIONS
VOLUME
ALKANES
CARBON COMPOUNDS
CARBON OXIDES
CHALCOGENIDES
ELEMENTS
HYDROCARBONS
NONMETALS
ORGANIC COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
SIMULATION
400201* - Chemical & Physicochemical Properties
030200 - Natural Gas- Reserves
Geology
& Exploration
020200 - Petroleum- Reserves
Geology
& Exploration