Simplified Compositional Models for Mixed Fluid Property Calculation

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Solution Overview

Problem

In subterranean hydrocarbon recovery from multiple reservoirs through a common surface network, existing methods face challenges in accurately modeling and optimizing fluid production due to the complexity of fluid characterization and pressure drop constraints, particularly in deepwater fields where flow lines are long and fluid compositions from different reservoirs mix.

Innovation Solution

The use of simplified compositional models, such as equation of state (EOS) and black oil models, to simulate fluid production and calculate properties of mixed fluids, allowing for the integration of surface and subsurface modeling by generating interpolation tables based on marker components unique to each reservoir, which simplifies the calculation of mixed fluid properties and replaces expensive phase equilibrium calculations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If full EOS phase equilibrium calculations are used to model mixed fluids from multiple reservoirs, then fluid property accuracy is improved, but computational cost and time increase significantly

Engineering Contradiction:
Improvefluid property accuracyVSAvoidcomputational time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The fluid system is segmented by introducing marker components that are unique to each reservoir. This allows the complex multi-reservoir fluid mixture to be divided into identifiable portions from each reservoir, enabling efficient tracking and property calculation without requiring full phase equilibrium calculations for the entire mixed system.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Marker components serve as intermediaries to represent and track fluids from different reservoirs. These marker components act as tracers that enable the system to identify and calculate properties of mixed fluids without requiring complete EOS phase equilibrium calculations, thus reducing computational time while maintaining accuracy.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If different EOS models with varying numbers of pseudo-components are used for each reservoir, then each reservoir's fluid characterization accuracy is improved, but integration complexity and model management difficulty increase

Engineering Contradiction:
Improvefluid characterization accuracyVSAvoidmodel integration complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The marker component approach provides a universal solution that works across multiple reservoirs with different EOS models. Each reservoir can maintain its own EOS characterization with appropriate pseudo-components, while the marker components provide a common framework for integrating and calculating properties of mixed fluids in the surface network.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The system changes the parameter representation by introducing marker components as additional tracking parameters. This allows the model to handle variable numbers of pseudo-components across different reservoirs while maintaining a consistent approach for calculating mixed fluid properties through the surface network.

Inventive Principle:
Principle #35Parameter changes

3Manufacturing precision

If detailed compositional modeling is performed for all fluids in the surface network, then production optimization accuracy is improved, but computational efficiency decreases

Engineering Contradiction:
Improveproduction optimization accuracyVSAvoidcomputational efficiency
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

Instead of performing detailed compositional modeling for all fluids throughout the entire surface network, the system applies detailed EOS modeling only where necessary (at reservoir outlets and mixing points) and uses marker component tracking for the remainder of the network. This partial application of detailed modeling maintains production optimization accuracy while significantly improving computational efficiency.

Inventive Principle:
Principle #16Partial or excessive action

Data Source

PatentEP3097483B1Simplified compositional models for calculating properties of mixed fluids in a common surface network
Publication Date: 2018.12.19 LANDMARK GRAPHICS CORP
  • EP3097483B1 patent drawingFigure 1A~1B
  • EP3097483B1 patent drawingFigure 2
  • EP3097483B1 patent drawingFigure 3

AI summary

System and methods of simulating fluid production in a multi-reservoir system with a common surface network are presented. An equation of state (EOS) characterization of fluids is matched with a delumped EOS model representing different components of the fluids for each reservoir within the multi-reservoir system. Fluid production in the multi-reservoir system is simulated for at least one simulation point in the common surface network, based in part on the delumped EOS model for each reservoir. If the fluids produced during the simulation at the simulation point are mixed fluids from different reservoirs, one or more interpolation tables representing the mixed fluids are generated and properties of the mixed fluids are calculated based on the generated interpolation tables. Otherwise, the properties of the fluids are calculated using the delumped EOS model corresponding to the reservoir from which the fluids are produced.