Downhole Molecular Weight Sensor via Gas Diffusion
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Solution Overview
Problem
Current methods for determining formation fluid chemistry, such as optical spectroscopy, provide approximate results for light end fractions and are highly matrix-dependent, making it difficult to accurately measure properties like gas-to-oil ratio (GOR) in real-time during exploration and recovery operations.
Innovation Solution
A molecular weight distribution sensor using gas diffusion is employed, comprising components like a sampling port, vaporization section, diffusion section, and detection section, which differentiates gas components based on molecular mass, allowing for accurate determination of molecular weight distribution in the downhole environment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If optical spectroscopy is used for compositional analysis of formation fluids, then the analysis can be performed down hole, but the results are only approximate for light end fractions and highly matrix dependent
Solution Approach 1:
The patent replaces optical spectroscopy (electromagnetic field-based method) with gas diffusion followed by mass spectrometry detection. The gas diffusion process separates components based on molecular mass, and the mass spectrometer provides direct molecular weight measurement, eliminating the matrix-dependent interpretation issues of optical methods.
Solution Approach 2:
The patent introduces a gas diffusion section as an intermediary between sample injection and detection. This diffusion process pre-separates the gas phase components based on molecular mass before they enter the mass spectrometer, enhancing the accuracy of molecular weight distribution determination and reducing matrix effects.
2Measurement precision
If mass spectrometry is used to determine molecular weight distribution, then direct measurement without prior separation is achieved, but the instrumentation is delicate and expensive
Solution Approach 1:
The patent divides the analytical system into distinct functional sections: a sampling port, a vaporization section, a gas diffusion section, and a detection section. This segmentation allows the complex mass spectrometry process to be broken down into manageable stages, with the gas diffusion section serving as a robust pre-separation stage that protects the delicate mass spectrometer from direct exposure to complex formation fluid matrices.
Solution Approach 2:
The patent performs gas diffusion and preliminary separation of components before they reach the mass spectrometer detector. This preliminary action based on molecular mass differences simplifies the subsequent detection process and reduces the complexity of data interpretation, making the overall system more practical for down hole applications.
3Productivity
If PVT derived properties are used to determine GOR, then the properties can be correlated from available data, but the results are not directly measured and are highly matrix dependent
Solution Approach 1:
The patent replaces PVT correlation methods (which rely on empirical relationships and matrix-dependent interpretations) with direct mass spectrometric measurement of molecular weight distribution. The gas diffusion process provides physical separation based on molecular mass, enabling direct calculation of GOR from measured molecular weights rather than from correlated PVT properties.
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
This approach enables precise, real-time determination of formation fluid characteristics, improving the accuracy of petroleum recovery operations by providing reliable molecular weight distribution data.
Implementation Method 1
a vaporization section to convert some part of the fluid sample into a gas phase
Implementation Method 2
A molecular weight distribution sensor that makes use of gas diffusion in the down hole environment
Data Source
AI summary
In some embodiments, apparatus and systems, as well as methods, may operate to draw a formation fluid sample into a sampling port included in a down hole tool, to vaporize some part of the fluid sample to substantially fill an injection port with a gas phase, to differentiate gas components in the gas phase to provide differentiated gas components along a concentration gradient, to detect the differentiated gas components, and to determine a fingerprint of the differentiated gas components. Other apparatus, systems, and methods are disclosed.