Table of Contents
- Overview: Fluid Object Definitions and Usage in OLI Studio: ScaleChem
- Brines
- Gas
- Hydrocarbon
- Whole Fluid
- Using ScaleChem Objects in Calculations
- Assumptions by Object
- Summary Table: Fluid Object Characteristics in OLI Studio: ScaleChem
- Caveats
- Conclusion: Key Considerations and Pitfalls
Overview: Fluid Object Definitions and Usage in OLI Studio: ScaleChem
In OLI Studio: ScaleChem, fluid modeling is organized through the use of specialized Objects, each representing different components of production and laboratory systems. These objects—Brines, Gases, Hydrocarbons (Oil), and Whole Fluids—enable precise simulation of fluid behavior and scale formation in multiphase systems. Understanding their definitions, assumptions, and intended use is critical for accurate results in both field and lab-based calculations.
Brines
Brines represent laboratory water samples in OLI Studio: ScaleChem. A Brine object typically includes cations, anions, dissolved gases, total dissolved solids, and alkalinity. By default, solids formation is prohibited, although the user can override this.
While brines can include a gas phase, this is not preferred. Any gases present in the sample should instead be modeled as a separate Gas object. Including vapor phases in brines complicates total volume reconciliation.
Gas
At measurement conditions, gas objects are entirely vapor. They may also include non-aqueous liquids (e.g., hydrocarbons) and aqueous phases, but these are secondary to the primary vapor-phase focus.
Hydrocarbon (Oil)
Like Gas objects, Hydrocarbon objects are centered around the liquid hydrocarbon phase (liquid-2). However, they may also include vapor and aqueous phases.
Whole Fluid
Whole Fluid objects can originate from any stream, not just OLI Studio: ScaleChem. These objects can include all phases and are the most comprehensive in terms of phase coverage.
Using OLI Studio: ScaleChem Objects in Calculations
OLI Studio: ScaleChem uses volumetric flow rates to define the presence of objects in a calculation. For instance:
The brine is specified in volume/time, and this example is set to 1000 m³/day
The flow unit specification can sometimes create confusion, especially when multiple phases are present.
Assumptions by Object
Brines
Flow represents only the liquid (liquid 1) phase. If solids are enabled, they are not included in the flow, and vapor phases are ignored.
Gases
The flow is based solely on the vapor phase. Any other phases (e.g., water, hydrocarbon) are adjusted and carried with the gas.
Hydrocarbons (Oil)
The flow is based only on the hydrocarbon liquid (liquid 2) phase. Additional phases are transported alongside.
Whole Fluids
Flow applies to all phases present in the object. This allows integration with Stream Analyzer data.
Summary Table: Fluid Object Characteristics in OLI Studio: ScaleChem
| Object Type | Primary Use | Included Phases | Flow Basis | Special Notes |
|---|---|---|---|---|
| Brine | Represents lab-analyzed water samples | Liquid (aqueous); optional solids and gases | Liquid phase (liquid-1) only | Solids excluded from flow; vapor discouraged for volume clarity |
| Gas | Models production gases | Vapor (primary); may include liquids and water | Vapor phase only | Secondary phases transported but not used for flow calculations |
| Hydrocarbon (Oil) | Captures liquid hydrocarbon streams | Liquid hydrocarbon (primary); vapor and water may be present | Hydrocarbon liquid phase (liquid-2) only | Other phases carried with flow but not considered primary |
| Whole Fluid | Represents complete multiphase streams | All present phases | Total flow of all phases | Must be used carefully—Stream Analyzer imports include every phase by default |
Caveats
Misuse of Whole Fluids can lead to incorrect assumptions. For example:
- The default flow includes all phases if a Stream Analyzer stream is used directly as a Whole Fluid.
- Only the liquid is considered if the same stream is used as a Brine. Solids are mathematically excluded.
- Using Whole Fluids as Gas or Hydrocarbon objects results in only the relevant phase being considered. Other phases are omitted from the flow basis.
Conclusion: Key Considerations and Pitfalls
The structured use of objects in OLI Studio: ScaleChem enables powerful and detailed fluid simulations. However, careful attention must be paid to object selection and flow assumptions to avoid misrepresentations.
Whole Fluid objects, while comprehensive, carry the risk of unintended inclusions—particularly when derived from Stream Analyzer data. Misapplication can lead to inconsistencies: for instance, the same stream interpreted as a Brine versus a Whole Fluid will produce different phase inclusions and flow calculations. Similarly, reclassifying Whole Fluids as Gas or Hydrocarbon objects strips out all non-primary phases.
Understanding these nuances ensures robust and consistent simulation results, maintaining fidelity in both predictive modeling and real-world decision support.