Asphaltene Concentration Simulation for Reservoir Characterization
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current methods for reservoir characterization struggle to accurately determine reservoir connectivity and compositional equilibrium, particularly in scenarios with non-equilibrium conditions due to factors like gravity, thermal gradients, biodegradation, and fluid migration, leading to inaccurate insights into reservoir fluid properties and compartmentalization.
Innovation Solution
A methodology that combines downhole fluid analysis (DFA) with the Yen-Mullins model and the Flory-Huggins-Zuo (FHZ) equation of state, simulating asphaltene disequilibrium in three dimensions over geological time, accounting for mechanisms like Darcy's law, molecular diffusion, gravitational diffusion, and thermal diffusion, to assess reservoir connectivity and compartmentalization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional reservoir characterization methods are used, then the evaluation process is simple, but the accuracy of determining reservoir connectivity and compositional equilibrium deteriorates under non-equilibrium conditions
Solution Approach 1:
The patent applies preliminary action by simulating asphaltene non-equilibrium concentration distributions over geological time using numerical models before conducting reservoir characterization. This pre-simulation establishes expected concentration profiles that account for gravitational, thermal, and biodegradation effects, enabling more accurate comparison with measured fluid samples and improving characterization accuracy under non-equilibrium conditions.
Solution Approach 2:
The patent employs parameter changes by incorporating multiple physical and chemical parameters into the numerical model, including gravitational effects, thermal gradients, biodegradation rates, and fluid migration patterns. By varying these parameters to reflect actual reservoir conditions, the model accurately reproduces non-equilibrium asphaltene distributions, thereby improving measurement precision without excessive complexity.
2Reliability
If non-equilibrium conditions are accounted for in reservoir characterization, then the accuracy of fluid property insights improves, but the complexity of analysis increases
Solution Approach 1:
The patent uses an intermediary approach by introducing a numerical model that acts as a mediator between theoretical non-equilibrium thermodynamics and practical reservoir characterization. The model translates complex physical processes (gravity, thermal gradients, biodegradation) into predicted asphaltene concentration distributions, which then serve as reference profiles for comparing with actual fluid samples, thereby improving reliability while managing analytical complexity.
Solution Approach 2:
The patent applies segmentation by dividing the reservoir characterization process into distinct components: (1) numerical simulation of asphaltene non-equilibrium distributions under various physical processes, (2) measurement of actual fluid sample compositions, and (3) comparison and interpretation. This segmentation allows each component to be optimized independently, improving overall reliability without overwhelming complexity.
3Measurement precision
If traditional equilibrium-based models are used, then the computational requirements are low, but the ability to accurately represent real reservoir conditions deteriorates
Solution Approach 1:
The patent applies partial action by focusing the numerical simulation specifically on asphaltene concentration distributions rather than modeling all fluid properties under non-equilibrium conditions. This targeted approach captures the essential non-equilibrium effects (gravity, thermal gradients, biodegradation) that most influence compositional equilibrium determination, thereby improving measurement precision while maintaining reasonable computational requirements.
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 accurate characterization of reservoirs by comparing simulated and measured asphaltene concentrations, providing insights into compositional equilibrium and disequilibrium, and aiding in reservoir production simulation and field development strategies.
Implementation Method 1
gradients are commonly observed in subterranean reservoirs due to a variety of mechanisms including, but not limited to, gravity, thermal gradients, biodegradation, active charging, water washing, and phase transitions
Implementation Method 2
The numerical model simulates non-equilibrium concentration distributions of a compositional component, such as asphaltenes, in a subterranean reservoir
Implementation Method 3
gradients are commonly observed in subterranean reservoirs due to a variety of mechanisms including, but not limited to, gravity, thermal gradients, biodegradation, active charging, water washing, and phase transitions
Implementation Method 4
Fluid may then be drawn into the downhole tool using the probe and/or packer
Data Source
AI summary
The present disclosure relates to a method for characterizing a hydrocarbon reservoir of interest traversed by at least one wellbore that includes (a) using a numerical model to simulate over geological time a non-equilibrium concentration of an asphaltene component as a function of location within the wellbore, (b) analyzing fluid samples acquired from at least one wellbore that traverses the reservoir of interest to measure concentration of the asphaltene component as a function of location within the wellbore, (c) comparing the non-equilibrium concentration of the asphaltene component as a function of location within the wellbore resulting from the simulation of (a) to the concentration of the asphaltene component as a function of location within the wellbore as measured in (b), and characterizing the reservoir of interest based upon the comparing of (c).