Schlumberger OLGA 2020.2

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.

Release updates

Improved functionality for pure CO2

To improve calculation accuracy, the CO2 viscosity model is replaced.

For simulations of pure CO2, OLGA 2020.2 includes an option to use predefined pressure and temperature ranges when generating the PVT table. The applied ranges are 0.001 to 100 MPa [0.145 to 14,503 psi] for pressure and –150 degC to 200 degC [–238 to 392 degF] for temperature.

Customized gridding ensures high accuracy in the areas where the fluid properties change Considerably, with small changes in pressure and enthalpy or pressure and temperature. This is useful if the operational conditions change significantly during the simulation.

To reduce nonphysical instabilities and improve convergence of the steady-state preprocessor, OLGA 2020.2 introduces an implicit coupling of heat transfer and flashing. 

You can now enter a negative value for one or both keys, TCONDENSATION and TBOILING under the SINGLEOPTIONS keyword. As before, large values for the time constants slow down the mass transfer, leading to a large nonequilibrium, while small values speed up the mass transfer, reducing the thermal nonequilibrium. If you enter a negative value, the time to reach equilibrium is
set equal to the time step.

Improved handling of low-pressure situations

When simulating low pressure systems with liquids that have very low vapor pressure (below atmospheric pressure), reduced numerical robustness can sometimes be encountered. To improve the numerical stability in such situations, it is now possible to use a special low-pressure handling feature. When activated, if below a defined pressure threshold, the OLGA simulator calculates the fluid properties and flashing with special consideration to avoid numerical problems.

New option for injection rate calculations

OLGA 2020.2 introduces a new key in the RESERVOIRCONTACT keywords. The key can be used to select how to convert the volume flow rate of reservoir fluid at standard conditions to in situ injection rate and improves usability for such scenarios.

Use of standard volume flow as function of drawdown in tabular inflow performance relationship

You can now tabulate the inflow performance as a volumetric phase flow rate at standard conditions versus pressure difference.

New input keys for defining reservoir contact pressure

Two new input keys are available in the RESERVOIRCONTACT keyword to set the drawdown mode as well as define the drawdown pressure at the reservoir contact. Both input keys are signal terminals that can be exposed on the OPC server.

New output variables for more accurate interpretation

Six new simulation output variables are added to enhance results interpretation, including four new boundary output variables and two new valve output variables.