Olga dynamic multiphase flow simulator

The Olga dynamic multiphase flow simulator is a comprehensive transient simulator for system design and production operations, that has been the industry standard tool for dynamic multiphase flow simulation for over four decades. It can be used in the energy industry for hydrocarbon flow predictions but also for CO₂ based flows, steam/water, nitrogen and other types of fluids. In addition to the principal flow model, the Olga simulator incorporates various other models essential for accurately simulating transient flow from reservoirs to processing units.

These models enable the calculation of pressure, temperature, flow regimes, liquid holdup, slug characteristics, and tracking of individual components. With this capability, users can design and operate production gathering and distribution systems with confidence.

The Olga simulator features a best-in-class three-layer flow model that handles gas, oil, and water. It adeptly manages single-phase to multiphase flows, including gas, oil, water, and solid phases, with different phases dispersed across various layers. The simulator solves a single energy equation and excels in handling both slow and fast transients. Additionally, the Olga simulator includes both a one-dimensional flow model (Olga simulator friction factor [FF]) and a three-dimensional flow model (HD model).

Typical flow assurance applications for transient analysis:

• Size pipelines to minimize backpressure, while maintaining stable flow rates and operating within the maximum allowable operating pressure (MAOP).
• Balance pipeline size against flow boosting to maximize accounting economics by using sophisticated sensitivity options.
• Model the benefits of parallel flowlines.
• Calculate optimal burial depth and insulation requirements.
• Identify risk for severe riser slugging.
• Accurately characterize fluid behavior with a wide variety of black oil and compositional fluid models.
• Size separation equipment and slug catchers to manage liquids associated with pigging operations, ramp-up surges, and hydrodynamic slug volumes.
• Identify the risk of potential solids formation including hydrates, asphaltenes, and scale.
• Assess the operational risk from deposition of wax in flowlines over time.
• Determine the amount of inhibitor to inject to avoid hydrate formation.
• Report many detailed variables (e.g., flow rates, pressure distribution, fluid properties, thermal properties, multiphase flow characteristics, and flow assurance parameters) over the length of the flow path.
• Visualize detailed reports at any point of interest including flow pattern maps and phase envelopes.
• Calculate cooldown time for shut-in.
• Optimize gas lift rates.

Due to lower maintainability and higher costs in offshore environments, all the design work and operational procedures require much more attention to detail. Verifying and developing plans for flow assurance activities in offshore, requires many simulations to be run, with sensitivity analysis and parametric studies. For onshore facilities and wells the scenarios are the same but simulations are run less often.

Yes, it does. The Olga simulator is particularly well suited for sophisticated thermal simulations. It is one-dimensional (calculates along the pipe axis), any two and three-dimensional effects must be modeled explicitly. The basic Olga simulator thermal model calculates the inner wall heat transfer coefficient. The built-in correlations are valid for natural and forced convection and for the transition between them. Flow pattern is accounted for. The user may specify pipe walls with material properties, including emissivity to account for radiation, and must give the ambient properties, that is, temperature and heat transfer coefficient. Based on this, the fluid temperature is calculated.

The Olga simulator can account for complex interactions between flow paths and surrounding solids, using a two-dimensional temperature field around flow paths. This is useful when modeling, for example, buried pipelines or complex risers.

• Accuracy is verified by OVIP since 1990s.
• Performance supported with over 40 years validated studies from the field.
• Versatility – Olga simulator can model a wider range of scenarios and systems than most other simulators on the market.
• Validated and trusted technology.
• Global footprint of support, consultancy and domain expertise.
• Integrates seamlessly with other SLB simulators and third-party simulators (e.g. Eclipse™ reservoir simulator, ROCX), Steady state converter (Pipesim™ steady-state multiphase flow simulator to Olga simulator), open OPC link to other simulators.

For pipelines:

• Composition of the fluids in the system and properties of all pseudo components, along with the equation of state for fluid characterization.
• Pipeline and flowline geometry data in tabulated format in spreadsheet.
• Production flow rates or inlet pressure.
• Wellhead or pipeline fluid inlet temperature.
• Delivery end pressure.
• Valve location.
• Valve closing time.
• Pipeline insulation and coating layers’ material properties.
• Pipe inner diameters, wall roughness, wall thickness and wall material composition.
• Pipeline wall material thermal conductivities, densities and heat capacities.
• Air and sea water temperatures.
• Speed of the air/water stream surrounding the pipelines under investigation

For wells:

• Well trajectories.
• Completion schematics.
• Fluid compositions for the reservoir fluid and lift gas.
• PVT reports if available. At least saturation pressure should be available to check the fluid characterization.
• Water depth and Rotary Kelly Bushing (RKB).
• Ambient temperature profile.
• Reservoir pressure and temperature.
• Inflow performance relationship (IPR) model (several zones with different IPR can be included).
• Wall material thermal properties and thickness of each layer or U-value for the wells.
• Well head choke valve characteristics.
• Gas lift valve characteristics.
• Dimensions of the gas lift injection line and available gas lift injection pressure.
• Outlet boundary conditions. The outlet boundary for the model is expected to be downstream the wellhead choke.

Olga Online™ production management system works in real-time and is designed with the needs of the modern production operation in mind. Offering all you need for multiphase flow assurance, powered by the Olga simulator.

There are several training options:

• Olga Well Dynamics (5 days)
• Olga Flow Assurance (5 days)
• Olga CCS Flow Assurance (5 days)

Comprehensive training catalog can be accessed on the SLB NExT Training website: NExTtraining/olga

Additional training for customer specific workflows and operations can be customized upon request.

Throughout the year, SLB organizes Olga simulator focused virtual webinars for global audiences. See the schedule on https://www.slb.com/products-and-services/delivering-digital-at-scale/production/flow-assurance-webinar-series. There are also scheduled User Group Meetings (UGMs) held annually in different parts of the world.

Carbon capture

The Olga simulator is one of the most effective simulators for CO₂ transport and injection available today. Flow assurance considerations and accurate simulation of CO₂ transport and injection are essential elements for successful CCS design and operations. Transient modeling is key to understanding complexity and uncertainties associated with CO₂ transport and  injection. 

The Olga simulator has been used for simulation of CO₂ systems for more than 15 years. It started with the single component functionality to model pure CO₂ back in 2009. Since then, we have validated Olga simulator modeling capabilities against high quality data from a flow loop built at the Institute for Energy Technology (IFE) in Norway.

With the pressure-enthalpy flash formulation made available in Olga 2017, we can now model CO₂ containing other components with higher accuracy and robustness.

We have continuous focus on both validation and development of new capabilities. The R&D project "CO₂ FACT” was concluded before “Olga CO₂ REACH” began in June 2022. “Olga CO₂ REACH” has been ongoing since 2022, and one of the outcomes of this R&D is a new solver, called “Olga New Solver (CCS)”, which became commercially available in Olga 2025.1 version released in December 2024.

Hydrogen

Simulations play an important role in the design and operation of hydrogen systems.
With the Olga simulator you can:

• Investigate variations in flow conditions and compositions along the pipeline over time, using a fit-for-purpose fluid modeling approach, where different options for fluid description are available:
• PVT table.
• Single component functionality—recommended for simulation of pure components.
• Compositional tracking:
• H2 + impurities.
• H2 + water.
• H2 mixes to track gas quality.
• Calculate flow rates and durations from potential small leaks to full pipe ruptures to identify propensity, size, and duration.
• Provide input to:
• Material and equipment selection considerations.
• Fire analysis (flow rates and duration).
• Explosion analysis—when combined with atmospheric dispersion computation (gas cloud size).
• Operational procedures.

Geothermal

The Olga simulator can accurately model geothermal, using the single component option, if pure water is used as a working fluid. Flow assurance considerations and accurate flow simulations give key insights for the optimal design and operation of geothermal systems.

The Olga simulator has unique capabilities to simulate dynamic operational scenarios.