Mud Filtrate Spectral Estimation for Downhole Fluid Analysis
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Solution Overview
Problem
Challenges in obtaining representative formation fluid samples during formation testing arise from contamination by miscible drilling fluids and invasion of drilling mud filtrate, which affects the accuracy of formation fluid characterization and reservoir evaluation.
Innovation Solution
Performing downhole fluid analysis to determine properties of mud filtrate in formation fluids, using these properties to inform subsequent analysis, and employing optical spectroscopy to measure optical densities at various wavelengths to characterize reservoir fluids and differentiate between formation and drilling fluid components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If downhole fluid analysis is performed on formation fluid, then real-time information on fluid properties is obtained, but accuracy is reduced due to mud filtrate contamination
Solution Approach 1:
The patent extracts and identifies the mud filtrate component from the contaminated formation fluid sample by analyzing optical density spectra. The system separates the spectral contribution of mud filtrate from the combined spectrum of formation fluid and mud filtrate, allowing accurate characterization of the formation fluid despite contamination.
Solution Approach 2:
The patent uses optical density measurements at multiple wavelengths as an intermediary to characterize both the formation fluid and mud filtrate. By measuring optical properties across a spectrum, the system can distinguish between different fluid components and determine their respective properties without physical separation.
2Measurement precision
If optical density measurements are performed at multiple wavelengths, then fluid characterization accuracy is improved, but measurement complexity increases
Solution Approach 1:
The patent employs a multi-wavelength optical density measurement system that serves multiple functions: characterizing formation fluid properties, identifying and quantifying mud filtrate contamination, and providing real-time analysis. This single measurement approach handles multiple analysis tasks simultaneously, reducing the need for separate measurement systems.
Solution Approach 2:
The patent changes the measurement parameter from single-wavelength to multi-wavelength optical density measurements. By measuring across a spectrum of wavelengths, the system captures different absorption characteristics of various fluid components, enabling more accurate fluid characterization and contamination identification.
3Measurement precision
If mud filtrate characteristics are determined and used in subsequent analysis, then analysis accuracy is improved, but processing requirements increase
Solution Approach 1:
The patent performs preliminary identification and characterization of mud filtrate properties from the optical density spectra before using this information in subsequent formation fluid analysis. By first determining the mud filtrate spectral signature and properties, the system can then accurately subtract or account for this contamination in the overall fluid characterization process.
Solution Approach 2:
The patent uses a feedback approach where the determined mud filtrate characteristics are fed back into the analysis process to improve formation fluid characterization. The identified mud filtrate properties inform the interpretation of subsequent measurements, allowing the system to continuously refine its analysis accuracy by accounting for contamination effects.
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 in-situ characterization of formation fluids, reduces contamination effects, and improves the accuracy of hydrocarbon identification and reservoir property estimation by using determined mud filtrate characteristics in further analysis.
Implementation Method 1
employing optical spectroscopy to measure optical densities at various wavelengths to characterize reservoir fluids and differentiate between formation and drilling fluid components
Data Source
AI summary
A method for using an optical spectrum of mud filtrate for analysis of fluid drawn from a formation is provided. The method includes performing downhole fluid analysis of formation fluid drawn at a wellbore measurement station and determining an optical spectrum of mud filtrate in the formation fluid drawn at the wellbore measurement station. The method also includes performing downhole fluid analysis of formation fluid drawn at an additional wellbore measurement station, and performing the downhole fluid analysis of formation fluid drawn at the additional wellbore measurement station includes using the determined optical spectrum of the mud filtrate in the formation fluid previously drawn at the wellbore measurement station. Additional methods, systems, and devices are also disclosed.