Group Contribution Equilibrium Model for Downhole Fluid Characterization
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Solution Overview
Problem
Current mud logging techniques suffer from inaccuracies that require correction factors determined through periodic laboratory testing, making real-time characterization of formation fluids during drilling operations challenging.
Innovation Solution
A method and system utilizing group contribution equations of state and phase equilibrium models to correct surface fluid data in real-time, allowing for the determination of total hydrocarbons in multiphase downhole fluids by analyzing gas samples extracted at the well site using a gas extractor and analytical instruments, without the need for additional laboratory testing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional Peng-Robinson equation of state is used for mud logging, then moderate success is achieved, but measurement precision deteriorates due to inaccuracies requiring correction factors
Solution Approach 1:
The patent changes the fundamental parameters of the equation of state model from traditional Peng-Robinson to a more sophisticated model that incorporates temperature-dependent binary interaction parameters and association effects. This parameter change improves measurement precision by accurately representing non-ideal gas behavior and liquid-phase associations without requiring external correction factors
Solution Approach 2:
The patent implements self-service by enabling the system to automatically determine accurate hydrocarbon profiles using real-time measurements and the improved equation of state model. The model self-corrects for non-ideal behavior through its inherent temperature-dependent parameters and association terms, eliminating the need for manual correction factors that would otherwise be required
2Measurement precision
If correction factors are determined through periodic laboratory testing, then measurement precision is improved, but productivity deteriorates due to time-consuming testing requirements
Solution Approach 1:
The patent applies preliminary action by pre-calculating and incorporating temperature-dependent binary interaction parameters and association constants into the equation of state model before field deployment. This preliminary preparation enables the model to automatically account for non-ideal behavior during real-time operations without requiring subsequent laboratory testing or correction factor determination
Solution Approach 2:
The patent substitutes the mechanical laboratory testing system with a computational model-based system. Instead of physically extracting samples for laboratory analysis to determine correction factors, the system uses the improved equation of state model with temperature-dependent parameters to calculate accurate hydrocarbon profiles directly from field measurements, replacing wet chemistry with computational thermodynamics
3Productivity
If real-time characterization is implemented, then productivity is improved, but measurement precision worsens due to lack of experimental correction factors
Solution Approach 1:
The patent changes the thermodynamic model parameters to include temperature-dependent binary interaction parameters and association constants, enabling the equation of state to accurately represent real gas and liquid behavior. This parameter enhancement allows real-time calculations to achieve laboratory-grade accuracy without requiring periodic sample extraction and correction factor determination
Solution Approach 2:
The patent introduces temperature-dependent binary interaction parameters and association constants as intermediary elements that mediate between the simplified real-time measurements and the complex non-ideal thermodynamic behavior. These intermediaries enable accurate prediction of phase behavior and hydrocarbon profiles during real-time operations without direct laboratory intervention
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables real-time characterization of formation fluids, providing accurate hydrocarbon profiles without the need for experimental correction factors, allowing for immediate adjustments to drilling operations based on characterized formation fluid data.
Implementation Method 1
solving a system of equations of state using a group contribution equilibrium model
Data Source
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AI summary
Methods and systems are disclosed to determine total hydrocarbons from fluid-carrying fluids and solids from a geological formation during downhole operations. Gas extraction at a well site occurs through a gas extractor at a set pressure, detected temperature, detected density, and controlled volume rate. The quantities of various components of interest are determined from samples of fluid influent and effluent from the wellbore by solving a system of equations of state using a group contribution equilibrium model. Knowing approximate chemical compositions of the liquid fluid and solid phases before contamination with formation materials, with the detection of the gas phase and description of the solid phase from the geological formation, allows for determination of total detectable hydrocarbons from geological formations at the surface, and their concentrations to be expressed as mole or mass fraction for materials coming from a wellbore while downhole operations.