Questions you can ask
- “Flash this gas at 20 C and 50 bara: 85% methane, 7% ethane, 3% propane, 2% n-butane, 3% decane. How much liquid drops out?”
- “What are the cricondenbar and cricondentherm of this gas condensate?”
- “Heating value and Wobbe index of this sales gas per ISO 6976.”
| Phase | Mole fraction | Density (kg/m3) | Viscosity (cP) |
|---|---|---|---|
| Gas | 0.940 | 42.8 | 0.0121 |
| Oil | 0.060 | 667 | 0.388 |
Illustrative values showing the shape of an answer, not live data.
About this source
Fluid phase behavior and gas quality for natural gas, condensate and oil compositions: TP flash, dew and bubble points, phase envelope, ISO 6976 heating value. Computed in-process with a TypeScript port of Equinor's open-source NeqSim library (SRK or Peng-Robinson cubic equation of state, NeqSim component data and binary interaction parameters); no external service, no setup. Give the composition as mole fractions of named components (methane through nC10, nitrogen, CO2, H2S, water, oxygen, argon, helium, hydrogen), temperature in C/F/K and absolute pressure in bara/psia.
Connector ID neqsim
Provenance
Freshness & coverage
Caveats
- ⚠ Cubic EoS (SRK or PR) with the classic mixing rule; association (CPA) for water/glycols is not modeled.
- ⚠ Supported components are the 21 pure components listed in the composition schema (no plus fractions).
› Methods (5)
Technical detail for developers: parameters, pagination, units, and freshness per method.
flashTP
readFlash a gas or oil composition at temperature and pressure: phases, density, Z, viscosity.
Required paramscompositiontemperaturepressureEntitiesfluid-phase-equilibriumPaginationnoneUnitsdensityKgPerM3: kg/m3 · molarVolumeM3PerMol: m3/mol · molarMassGPerMol: g/mol · viscosityCp: cP · moleFraction: mol/molFreshnessStatic- ⚠ Two-phase (vapor-liquid or vapor-aqueous) flash; three-phase splits are not computed.
- ⚠ densityKgPerM3 includes the Peneloux volume shift; compressibilityFactor is the untranslated EoS value.
SRK default, pr optional; returns phase fractions and compositions.
dewPointTemperature
readHydrocarbon dew point temperature of a gas composition at a given pressure.
Required paramscompositionpressureEntitiesdew-pointPaginationnoneFreshnessStatic- ⚠ Hydrocarbon dew point only; the water dew point needs CPA and is not computed.
Returns the incipient liquid composition; none above the maximum dew pressure.
bubblePointPressure
readBubble point (saturation) pressure of an oil or liquid composition at a temperature.
Required paramscompositiontemperatureEntitiesbubble-pointPaginationnoneFreshnessStaticReturns the incipient vapor composition; below the critical temperature.
phaseEnvelope
readPhase envelope (PT diagram) of a gas composition: cricondentherm, cricondenbar, critical point.
Required paramscompositionEntitiesphase-envelopePaginationnoneFreshnessStatic- ⚠ Vapor-liquid envelope only; three-phase regions are not traced. closed=false marks a partial curve.
- ⚠ Computation is capped at 15 seconds; on expiry the call fails with a timeout error (no partial curve).
Dew and bubble curve points, thinned to maxPoints (default 120).
gasQualityISO6976
readNatural gas heating value (GCV, NCV), Wobbe index and relative density per ISO 6976.
Required paramscompositionEntitiesgas-qualityPaginationnoneUnitscalorificValue: see calorificValueUnit · density: kg/m3 · molarMass: g/molFreshnessStatic- ⚠ Reference pressure 101.325 kPa; real-gas values use the ISO 6976 summation-factor method.
ISO 6976:2016 default; 15/15 C references; per m3, kg or mol.