NeqSim Functionality Review for Oil & Gas Installation Design and Operations

Review Date: January 31, 2026
Version Reviewed: NeqSim 3.3.0
Scope: Onshore and Offshore Oil & Gas Installations

Executive Summary

NeqSim is a comprehensive Java-based thermodynamic and process simulation toolkit with strong capabilities for oil and gas applications. This review evaluates its functionality for designing and operating both onshore and offshore installations, identifying strengths and areas for improvement.

Overall Assessment:

1. STRONG FUNCTIONALITY (Well-Developed Areas)

1.1 Thermodynamic Foundation (Excellent)

Strengths:

Code Example Location: src/main/java/neqsim/thermo/system

1.2 Process Equipment Library (Very Good)

Comprehensive Equipment Coverage:

Category Equipment Types Maturity
Separators 2-phase, 3-phase, gas scrubbers, hydrocyclones ★★★★★
Compressors Centrifugal with performance charts, surge/stone wall, anti-surge ★★★★★
Heat Exchangers Shell & tube, multi-stream, air coolers, heaters/coolers ★★★★☆
Pumps Standard pumps, ESP (Electric Submersible Pump) ★★★★☆
Valves Control, safety/relief, HIPPS, ESD, PSD, blowdown, check ★★★★★
Distillation Tray columns, multiple solvers (direct, damped, inside-out) ★★★★☆
Pipelines Adiabatic pipe, Beggs & Brill, Two-Fluid transient, riser models ★★★★★
Reactors Gibbs reactors, furnace burners ★★★☆☆
Subsea Trees, manifolds, PLET/PLEM, jumpers, umbilicals ★★★★☆

Notable Features:

Code Locations:

1.3 Mechanical Design Framework (Very Good)

Strengths:

Code Location: src/main/java/neqsim/process/mechanicaldesign

1.4 Safety Systems (Very Good)

Implemented Safety Features:

Feature Description Status
Depressurization/Blowdown Dynamic vessel blowdown with multiple thermodynamic modes ★★★★★
Fire Case Modeling API 521 pool fire, jet fire heat loads ★★★★☆
Relief Valve Sizing API 520/521 compliant PSV sizing ★★★★☆
HIPPS High Integrity Pressure Protection Systems ★★★★☆
ESD Valves Emergency shutdown valve modeling ★★★★☆
Safety Envelopes Hydrate, WAX, MDMT envelope calculations ★★★★☆
Risk Framework Monte Carlo, bow-tie, SIS/SIF integration ★★★★☆

Advanced Risk Analysis:

Code Locations:

1.5 Gas Quality & Standards (Very Good)

Implemented Standards:

Code Location: src/main/java/neqsim/standards/gasquality

1.6 ProcessSystem & Flowsheet Management (Very Good)

Capabilities:

Code Location: src/main/java/neqsim/process/processmodel

2. MODERATE FUNCTIONALITY (Adequate but Could Be Enhanced)

2.1 Flow Assurance (Good, With Erosion Modeling)

Current Capabilities:

Erosion-Corrosion Modeling:

Feature Class Description
API RP 14E ManifoldMechanicalDesignCalculator Ve = C/√ρ with configurable C-factor
Velocity Checks calculateErosionalVelocity() Gas, liquid, multiphase limits
Sand Effects Via C-factor adjustment C=100 clean, C=125-150 with solids

Code Example:

ManifoldMechanicalDesignCalculator calc = new ManifoldMechanicalDesignCalculator();
calc.setErosionalCFactor(100.0);  // Clean service
calc.setMixtureDensity(pipe.getMixtureDensity());
double ve = calc.calculateErosionalVelocity();  // m/s

// Check actual vs erosional
double actualV = pipe.getMixtureVelocity();
boolean safe = actualV < ve * 0.8;  // 80% margin

Minor Gaps:

Note: Slug flow is well-handled via TwoFluidPipe + SlugTracker (see Pipeline section)

Code Location: src/main/java/neqsim/pvtsimulation/flowassurance

2.2 Pipeline & Multiphase Flow (Very Good)

Current Models:

Minor Gaps:

2.3 MPC/Control Integration (Good, Needs Enhancement)

Current Capabilities:

Limitations:

Code Location: src/main/java/neqsim/process/mpc

2.4 Field Development Tools (Good, Needs Enhancement)

Current Features:

Well Performance Capabilities: | Feature | Description | Status | |———|————-|——–| | IPR Models | Production Index, Vogel, Fetkovich, Backpressure, Table | ✓ Implemented | | Multi-Layer Wells | Commingled production with individual layer contributions | ✓ Implemented | | VFP Table Export | VFPPROD/VFPINJ for Eclipse coupling | ✓ Implemented | | Tubing Performance | Integration with PipeBeggsAndBrills for VLP | ✓ Implemented |

Code Location: src/main/java/neqsim/process/equipment/reservoir/WellFlow.java

Reservoir Coupling:

Code Location: src/main/java/neqsim/process/fielddevelopment/reservoir/ReservoirCouplingExporter.java

Limitations:

Code Location: src/main/java/neqsim/process/fielddevelopment

3. WEAK FUNCTIONALITY (Areas Requiring Significant Development)

3.1 Offshore-Specific Operations (Needs Development)

Missing/Limited Features:

Partial Coverage:

3.2 Rotating Equipment Operations (Good, With Enhanced Driver Support)

Current State:

Driver Modeling (Implemented):

Driver Type Class Capabilities
Gas Turbine GasTurbineDriver Ambient derating (temp/altitude), part-load efficiency, fuel consumption
Electric Motor ElectricMotorDriver VFD speed control, efficiency curves, power factor
Steam Turbine SteamTurbineDriver Extraction/condensing, steam rate curves

Condition Monitoring (Implemented):

Feature Class Description
Vibration Analysis FlowInducedVibrationAnalyser LOF/FRMS methods, support arrangement modeling
Health Monitoring ConditionBasedReliability Multi-indicator health index, RUL estimation
Degradation Models DegradationModel enum Linear, Exponential, Weibull, ML-based

Condition Indicators Supported:

Minor Gaps:

3.3 Utilities & Support Systems (Moderate Coverage)

Implemented Features:

System Class/Package Capabilities Status
Flare Stack FlareStack Radiation modeling (Point Source, Chamberlain), tip backpressure, emissions ★★★★☆
Flare Flare Basic flare equipment, mass balance ★★★☆☆
Gas Turbine GasTurbine Power generation, fuel consumption, emissions ★★★★☆
Fuel Cell FuelCell Hydrogen/natural gas fuel cells ★★★☆☆
Electrolyzer Electrolyzer Water electrolysis for H2 production ★★★☆☆
Solar/Wind powergeneration package Basic renewable energy models ★★☆☆☆

Flare System Capabilities:

Code Location: src/main/java/neqsim/process/equipment/flare

Partially Implemented:

Not Implemented:

3.4 Operational Diagnostics & Monitoring (Needs Development)

Missing Features:

3.5 Dynamic Simulation (Good)

Current State:

Minor Gaps:

4. IMPROVEMENT SUGGESTIONS

4.1 High Priority (Critical for O&G Design/Operations)

Area Improvement Benefit Status
Erosion-Corrosion API RP 14E erosional velocity with sand Pipeline/choke integrity ✅ Implemented in ManifoldMechanicalDesignCalculator
Pipeline Network Network topology solver with looped systems Required for gathering systems ✅ Implemented (LoopedPipeNetwork)
Inhibitor Management Track MEG/TEG through system with losses Flow assurance operations ⚠️ Partial
Digital Twin Interface REST API / OPC-UA connector layer Real-time operations ⚠️ Partial

Erosion-Corrosion Implementation:

The ManifoldMechanicalDesignCalculator class implements API RP 14E erosional velocity calculation:

// Calculate erosional velocity per API RP 14E
// Ve = C / sqrt(ρ_mix) where C = 100-150 typically
calculator.setErosionalCFactor(100.0);
calculator.setMixtureDensity(rhoMix);
double erosionalVelocity = calculator.calculateErosionalVelocity();

Code Location: src/main/java/neqsim/process/mechanicaldesign/manifold/ManifoldMechanicalDesignCalculator.java

4.2 Medium Priority (Enhances Capability)

Area Improvement Benefit
FPSO Operations Motion effects on separation, riser slugging Floating production design
Condition Monitoring Equipment health tracking, RUL estimation Predictive maintenance
Well Performance IPR curves, artificial lift optimization Production optimization
Scale Prediction CaCO₃, BaSO₄, etc. precipitation Water handling
Crude Compatibility Blending stability predictions Operations planning
Emissions Intensity CO₂/CH₄ per unit production tracking ESG reporting

4.3 Lower Priority (Nice-to-Have)

Area Improvement Benefit
Offshore Logistics Supply vessel, helicopter scheduling OPEX estimation
Integrity Management Corrosion rate tracking, inspection planning Asset integrity
Training Simulator OTS-compatible output format Operator training
CO₂ Sequestration Injection well modeling CCUS applications

5. DETAILED FEATURE GAP ANALYSIS

5.1 Onshore Applications

Application NeqSim Capability Gap
Gas Processing Plant ★★★★☆ Very Good Amine regeneration could be improved
Oil Terminal ★★★★☆ Very Good Tank mixing/blending limited
Refinery Integration ★★★☆☆ Good Reactor modeling limited
Pipeline Network ★★★★☆ Very Good Looped network solver implemented
Compression Station ★★★★★ Excellent Well covered
Gas Gathering ★★★★☆ Very Good Slug catcher sizing basic

5.2 Offshore Applications

Application NeqSim Capability Gap
Fixed Platform ★★★★☆ Very Good Minor gaps only
FPSO ★★★☆☆ Good Motion effects, offloading
Subsea Production ★★★★☆ Very Good TwoFluidPipe provides transient flow
TLP/Spar/Semi ★★★☆☆ Good Motion effects
Subsea Tieback ★★★★☆ Very Good Long-distance flow assurance
Gas Export ★★★★☆ Very Good Mostly complete

6. COMPARISON WITH COMMERCIAL TOOLS

Feature Area NeqSim HYSYS/UniSim OLGA/LedaFlow PIPESIM
Thermodynamics ★★★★★ ★★★★★ ★★★☆☆ ★★★★☆
Steady-State Process ★★★★☆ ★★★★★ ★★☆☆☆ ★★★☆☆
Transient Multiphase ★★★★☆ ★★★☆☆ ★★★★★ ★★★★★
Mechanical Design ★★★★☆ ★★★☆☆ ★★☆☆☆ ★★★☆☆
Safety Analysis ★★★★☆ ★★★☆☆ ★★☆☆☆ ★★☆☆☆
Cost Estimation ★★★★☆ ★★★☆☆ ★☆☆☆☆ ★★☆☆☆
Open Source/API ★★★★★ ★★☆☆☆ ★★☆☆☆ ★★☆☆☆
Python Integration ★★★★★ ★★★☆☆ ★★★☆☆ ★★★☆☆

NeqSim Competitive Advantages:

  1. Open source with full code access
  2. Excellent thermodynamic foundation
  3. Strong Python/Java API
  4. Integrated mechanical design
  5. Comprehensive safety framework
  6. Active development community

Phase 1: Critical Operations Features (✅ Largely Complete)

  1. ✅ Pipeline network solver for looped systems (LoopedPipeNetwork)
  2. ⚠️ Digital twin REST API layer (partial)
  3. ❌ OPC-UA data connector
  4. ⚠️ Enhanced TwoFluidPipe validation against field data
  5. ⚠️ Slug catcher sizing based on SlugTracker statistics

Phase 2: Enhanced Flow Assurance (In Progress)

  1. ⚠️ MEG/TEG tracking system-wide
  2. ❌ Scale prediction (at least CaCO₃)
  3. ✅ Erosion velocity calculations (API RP 14E)
  4. ⚠️ Pigging simulation basic
  5. ⚠️ Sand transport modeling

Phase 3: Offshore Operations (12-18 months)

  1. ❌ FPSO motion effects
  2. ✅ Riser slugging prediction (SevereSlugAnalyser)
  3. ❌ Offloading simulation
  4. ⚠️ Subsea processing enhancements
  5. ❌ Marine operations integration

Phase 4: Operational Excellence (12-18 months)

  1. ✅ Advanced condition monitoring (ConditionBasedReliability)
  2. ⚠️ Production optimization framework
  3. ⚠️ Integrity management module
  4. ❌ Training simulator export
  5. ⚠️ ESG/emissions tracking enhancements

8. CONCLUSION

NeqSim provides a strong foundation for oil and gas installation design and operations with particular excellence in:

The remaining gaps are in:

For design applications, NeqSim is highly capable and competitive with commercial tools. For operations applications, additional development in real-time integration would further enhance its value.

Recommendation: NeqSim is well-suited for conceptual and detailed design of oil and gas facilities, including transient multiphase flow analysis via TwoFluidPipe and looped pipeline networks via Hardy Cross solver. For operational support, it can serve as a calculation engine within a larger digital architecture.

Appendix A: Package Structure Reference

neqsim/
├── thermo/                    # Thermodynamic core
│   ├── system/               # EoS implementations (50+)
│   ├── phase/                # Phase models
│   └── component/            # Component data
├── thermodynamicoperations/   # Flash & phase envelope
│   └── flashops/             # All flash types
├── process/                   # Process simulation
│   ├── equipment/            # Unit operations
│   │   ├── separator/
│   │   ├── compressor/
│   │   ├── heatexchanger/
│   │   ├── pipeline/
│   │   ├── valve/
│   │   ├── pump/
│   │   ├── distillation/
│   │   ├── subsea/
│   │   └── ...
│   ├── mechanicaldesign/     # Equipment sizing & costs
│   ├── safety/               # Safety systems & risk
│   ├── mpc/                  # Control integration
│   └── fielddevelopment/     # Project economics
├── standards/                 # Industry standards
│   └── gasquality/           # ISO, GERG, etc.
├── pvtsimulation/            # PVT experiments
│   └── flowassurance/        # Hydrate, wax, asphaltene
└── fluidmechanics/           # Pipe flow models

Core Documentation

Process & Equipment

Mechanical Design

Safety & Risk

Risk Analysis

Cost Estimation

Subsea Systems

Examples

Appendix C: New Functionality Reference

Looped Pipeline Network Solver

Classes:

Key Features:

Example:

LoopedPipeNetwork network = new LoopedPipeNetwork("Distribution Ring");
network.setFluidTemplate(gas);
network.addSourceNode("supply", 50.0, 2000.0);
network.addJunctionNode("A");
network.addJunctionNode("B");
network.addSinkNode("customer", 2000.0);
network.addPipe("supply", "A", "inlet", 1000.0, 0.3);
network.addPipe("A", "B", "ring1", 500.0, 0.2);
network.addPipe("B", "supply", "ring2", 500.0, 0.2);  // Creates loop
network.addPipe("A", "customer", "outlet", 200.0, 0.15);
network.run();

Compressor Driver Framework

Classes:

Condition-Based Reliability

Class: ConditionBasedReliability

Indicator Types: VIBRATION, TEMPERATURE, PRESSURE, FLOW, CURRENT, WEAR, CORROSION, EFFICIENCY, ACOUSTIC, OIL_ANALYSIS

Flow-Induced Vibration Analysis

Class: FlowInducedVibrationAnalyser

Methods: LOF (Likelihood of Failure), FRMS (Fatigue Reduced Modulus of Safety)

Reservoir Coupling

Class: ReservoirCouplingExporter

Export Formats: Eclipse 100, E300 Compositional, Intersect, CSV

Well Performance (IPR)

Class: WellFlow

IPR Models: PRODUCTION_INDEX, VOGEL, FETKOVICH, BACKPRESSURE, TABLE

Document prepared as part of NeqSim capability assessment for oil and gas applications.