New Software Release

Olga 2023 Now Available

Thursday, 13 July 2023

Product overview

The Olga™ dynamic multiphase flow simulator models transient flow (time-dependent behaviors) to maximize production potential. Transient modeling is an essential component for feasibility studies and field development design. Dynamic simulation is essential in deep water and is used extensively in both offshore and onshore developments to investigate transient behavior in pipelines and wellbores. Transient simulation with the Olga simulator provides an added dimension to steady-state analysis by predicting system dynamics, such as time-varying changes in flow rates, fluid compositions, temperature, solids deposition, and operational changes. 

From wellbore dynamics for any well completion to pipeline systems with various types of process equipment, the Olga simulator provides an accurate prediction of key operational conditions involving transient flow.

Learn more about Olga

Release updates

Olga Model Management

Olga 2023 is being released with Olga Model Management compatibility. 
Olga Model Management is a cloud-powered model management solution providing a unified, collaborative ecosystem where models can be easily shared between different types of consumers such as:  

  • Existing users of the Olga simulator on laptop or desktop 
  • Existing users on the Delfi™ digital platform
  • Web applications: cloud and edge digital workflow solutions 
  • Digital services: scalable simulation, calibration, machine learning (ML)

Olga 2023 is released with the possibility of: 

  • Opening Olga simulator cases from Olga Model Management
  • Running cases locally 
  • Publishing models and simulation results back to Olga Model Management
  • Keeping track of model versions and changes
  • Easily comparing cases

The solution is subscription based. The user will need a Delfi user account and an Olga simulator license. 

The Olga simulator GUI will have some new functionality related to Olga Model Management. As can be seen from the screenshot in Figure 1 below, “Open Case From Cloud” is included in this new version.

Reynolds number

Reynolds number for the gas, oil, and water layers are exported as output variables.

Previously, Reynolds numbers for each of the layers in the Olga simulator were not accessible to users. In this release, they are being made available as part of boundary variables. There are three new variables for separated flow: gas (REYGSEP) , oil (REYHLSEP), water (REYWTSEP), and three new variables for dispersed flow: gas (REYGDISP), oil (REYHLDISP) , water (REYWTDISP). The separated flow Reynolds numbers are non-zero if the gas-liquid flow regime is stratified (ID=1) or annular (ID=2), unless the respective layer(s) is absent in the system, while the dispersed flow Reynolds numbers are all zero. The reverse is true if the gas-liquid flow regime is bubbly flow (ID=4). If slug flow prevails (ID=3), then all Reynolds numbers are non-zero except when the respective layer(s) is absent. The separated Reynolds numbers correspond to the bubble zone Reynolds number while the dispersed Reynolds numbers correspond to the slug zone Reynolds number. The non-zero values have lower limit of 0.1.

Use of saturation curve for temperature of a source and a node

A new subkey, saturation temperature (TSAT), is added to source, pressure node, and mass flow node.  TSAT can be off or on, with off as the default. This subkey can be used only if “COMPOSITION=SINGLE” or “STEAMWATER_HC”. When the TSAT is set to off, the temperature must be specified. When the TSAT is set to on and “COMPOSITION=STEAMWATER_HC”, the temperature is calculated based on the water saturation curve at the given pressure and user must input “STEAMFRACTION”.  When the TSAT is set to on and “COMPOSITION=SINGLE”, the temperature is calculated based on the saturation curve of the single component at the given pressure and user must input “GASFRACTION”.

New output variables for mass flow fraction

The following trend and profile output variables are now available as mass flow fractions at a section boundary, using absolute flowrates (STEAMWATER-HC fluid option).

New output variables
 GASFMFR  Gas mass fraction relative to total mass rate of gas, oil and water phase
 OILFMFR  Oil mass fraction relative to total mass rate of gas, oil and water phase
 WATFMFR  Water mass fraction relative to total mass rate of gas, oil and water phase

Further details on changes to Olga 2023 can be found in the Olga simulator release notes which are available for download via the production software download server on the SLB Software Download Center.


The product is suitable for use by production, process, and flow assurance engineers, and those involved in multiphase flow simulation.