Downhole Fluid Analysis for Reservoir Compartmentalization

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Solution Overview

Problem

Conventional downhole fluid analysis techniques fail to accurately detect compartmentalization and non-equilibrium hydrocarbon distribution in reservoirs, leading to erroneous interpretations and potential loss of economically viable production.

Innovation Solution

A downhole fluid analysis tool employing compositional measurements and equations of state (EOS) to predict compositional gradients with depth, accounting for gravitational, chemical, and thermal forces, allowing for real-time comparison with measured data to determine reservoir properties such as compartmentalization and layer connectivity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional downhole fluid analysis techniques are used, then the analysis process is simple, but the measurement precision is insufficient to accurately detect compartmentalization and non-equilibrium hydrocarbon distribution

Engineering Contradiction:
Improvedetection accuracy of compartmentalizationVSAvoidcomplexity of analysis method
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent segments the reservoir into multiple compartments and analyzes compositional gradients at different depths separately. By dividing the reservoir into discrete zones and evaluating compositional differences between them, the method can detect compartmentalization more accurately without requiring a single complex analysis model for the entire reservoir.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent changes the analytical parameters by using compositional gradients (changes in hydrocarbon composition with depth) as the key indicator for detecting compartmentalization. Instead of relying on single-point measurements, the method analyzes how composition parameters vary with depth, enabling more precise detection of reservoir heterogeneity and non-equilibrium conditions.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If conventional downhole fluid analysis techniques are used, then the device complexity is low, but the reliability of reservoir interpretation is poor leading to erroneous conclusions

Engineering Contradiction:
Improveaccuracy of reservoir interpretationVSAvoidcomplexity of analysis system
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent implements feedback by comparing measured compositional gradients with expected gradients under equilibrium conditions. The system uses this comparison to identify deviations that indicate compartmentalization or non-equilibrium states, providing a feedback mechanism that continuously refines the interpretation and improves reliability by validating assumptions against actual measurements.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent performs preliminary analysis by establishing expected compositional gradients based on equilibrium assumptions before comparing them with actual measurements. This preliminary model provides a reference framework that enables more reliable interpretation by highlighting deviations from expected behavior, allowing the system to identify compartmentalization and non-equilibrium conditions more confidently.

Inventive Principle:
Principle #10Preliminary action

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 detection of compartmentalization and non-equilibrium hydrocarbon distribution, improving reservoir understanding and production efficiency by providing real-time, accurate compositional data and property gradients.

Implementation Method 1

The fluid analysis module performs spectrophotometry measurements that measure absorption spectra of the sample and translates such spectrophotometry measurements into concentrations of several alkane components and groups in the fluids of interest.

Methodology Applied
Scientific EffectSpectrophotometry: Absorption Spectroscopy

Implementation Method 2

Compositional gradients with depth can be predicted with equations of state (EOS) that take into account the impacts of gravitational forces, chemical forces, thermal diffusion, etc.

Methodology Applied
Scientific EffectGravitational separation: Gravitation

Implementation Method 3

Compositional gradients with depth can be predicted with equations of state (EOS) that take into account the impacts of gravitational forces, chemical forces, thermal diffusion, etc.

Methodology Applied
Scientific EffectThermal diffusion: Diffusion

Data Source

PatentUS7822554B2Methods and apparatus for analysis of downhole compositional gradients and applications thereof
Publication Date: 2010.10.26 SCHLUMBERGER TECH CORP
  • US7822554B2 patent drawing
  • US7822554B2 patent drawing
  • US7822554B2 patent drawing

AI summary

A method and system are provided for characterizing a reservoir of interest by comparing measured downhole fluid analysis measurement data with predicted downhole fluid analysis measurement data for the corresponding depth within the reservoir. The downhole fluid analysis measurement data may comprise the results of compositional analysis, gas-oil ratio measurements, and spectrophotometry measurements. The compositional analyses may be delumped to characterize the compositional components of the downhole fluid and equations of state may be used to predict compositional gradients and fluid properties with depth. The method and system enable the user to characterize a reservoir as to its states of compartmentalization and equilibrium.