title: Flow Assurance in NeqSim description: “Guide to NeqSim flow-assurance screening for hydrates, wax, asphaltenes, scale, corrosion, erosion, emulsions, and pipeline cooldown.” —
Flow assurance keeps hydrocarbon fluids transportable during production, shutdown, and restart. NeqSim combines thermodynamic models with screening calculators for identifying risks and comparing mitigation options. Treat every screening result as input to an engineering assessment, not as design certification.
Choose a workflow
| Topic | Start here |
|---|---|
| Integrated study sequence | Flow-assurance overview |
| Cooldown, simplified corrosion, mineral scale, and wax curves | Screening-tools guide |
| Hydrates | Hydrate models |
| Wax fluid characterization | Wax characterization |
| Asphaltenes | Asphaltene modeling |
| Sand erosion | Erosion prediction |
| Emulsions | Emulsion viscosity |
| High-salinity scale and treatment evidence | Mineral-scale and chemical-treatment validation |
Screening classes
The following classes are in neqsim.pvtsimulation.flowassurance.
| Class | Purpose |
|---|---|
PipelineCooldownCalculator |
Lumped-parameter shutdown cooldown from explicit geometry, thermal, fluid, and boundary inputs |
SurfCooldownAnalyzer |
NeqSim-fluid wrapper that calculates properties and hydrate equilibrium before the lumped cooldown screen |
DeWaardMilliamsCorrosion |
Simplified CO2-corrosion screening with empirical correction factors |
ScalePredictionCalculator |
Saturation indices for common mineral scales |
PitzerScaleActivityModel |
Activity coefficients for high-salinity brines |
MultiMineralScaleEquilibrium |
Coupled shared-ion mineral precipitation equilibrium |
WaxCurveCalculator |
Wax-fraction curves, WAT results, monotonicity correction, and flash diagnostics |
ErosionPredictionCalculator |
API RP 14E velocity and DNV RP O501 erosion screening |
EmulsionViscosityCalculator |
Effective viscosity and phase-inversion screening |
For process-coupled corrosion and materials workflows in neqsim.process.corrosion, see the
corrosion analysis module.
Canonical executable example
The screening-tools guide contains the maintained Java 8
program for cooldown, simplified corrosion, and scale screening, plus the current wax-curve API
contract. FlowAssuranceDocumentationTest executes the documented calls and checks result bounds.
Keeping one canonical program prevents landing-page fragments from drifting independently.
The example states every unit and preserves JSON outputs that can be paired with stable case or asset identities, input provenance, model/version information, and data-quality diagnostics in a larger workflow. The calculators do not add that governance automatically.
Select an asphaltene method
| Need | Class or guide | Notes |
|---|---|---|
| Fast empirical screen | DeBoerAsphalteneScreening |
Requires reservoir pressure, saturation pressure, and in-situ density |
| CPA stability analysis | AsphalteneStabilityAnalyzer |
See CPA calculations |
| Compare available methods | AsphalteneMethodComparison or AsphalteneMultiMethodBenchmark |
See method comparison |
| Regular-solution model | FloryHugginsAsphalteneModel |
Configure and calibrate for the fluid being studied |
| Refractive-index screen | RefractiveIndexAsphalteneScreening |
Requires measured or estimated refractive-index inputs |
| Cubic-EOS characterization | PedersenAsphalteneCharacterization |
Adds characterized pseudo-components and supports binary-interaction tuning |
| CPA parameter fitting | AsphalteneOnsetFitting |
See parameter fitting |
| Pressure-onset flash | neqsim.thermodynamicoperations.flashops.saturationops.AsphalteneOnsetPressureFlash |
Run the flash object and read getOnsetPressure() |
| Temperature-onset flash | neqsim.thermodynamicoperations.flashops.saturationops.AsphalteneOnsetTemperatureFlash |
Run the flash object and read its onset result |
For a quick empirical classification, use the maintained De Boer screening guide. The implementation uses absolute reservoir and saturation pressure in bar and in-situ oil density in kg/m3. A flagged case still requires measured onset or precipitation data and a calibrated model.
The PhaseType enum includes ASPHALTENE for a solid asphaltene-rich phase and
LIQUID_ASPHALTENE for the liquid-liquid Pedersen approach. Phase appearance and type depend on
the selected model, enabled phase checks, composition, and flash conditions; adding an asphaltene
component alone does not guarantee a precipitated phase.
NeqSim includes an asphaltene database component for CPA workflows. Its default parameters are
generic starting values. For cubic-EOS workflows, PedersenAsphalteneCharacterization creates
case-specific pseudo-components. Tune either approach to measured onset or precipitation data
before using it for design decisions.