Multi-Envelope Spectroscopy for Gas-Oil Ratio Measurement
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Solution Overview
Problem
Current methods for measuring Gas-Oil Ratio (GOR) in crude oil extraction using near-infrared spectroscopy are limited by their ability to accurately determine methane concentration, especially in the presence of interfering gases like H2S and CO2, and require narrow spectral ranges, which restricts their applicability.
Innovation Solution
The use of broad-band absorption spectroscopy with multiple spectroscopic envelopes to select and measure spectral portions of light passing through a sample, allowing for the determination of component concentrations by analyzing absorbance across a wider spectral range, including regions affected by methane, CO2, and other gases.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a single spectroscopic envelope is used to measure GOR, then the measurement method is simple, but the accuracy and dynamic range are limited
Solution Approach 1:
The patent divides the broad spectral range into multiple discrete spectroscopic envelopes (e.g., first envelope at 1620-1700 nm, second envelope at 2100-2300 nm). Each envelope targets specific absorption bands of different components (methane, CO2, H2S). By segmenting the measurement into multiple targeted spectral regions rather than using a single broad measurement, the system achieves higher accuracy for each component while maintaining a manageable system structure through modular envelope selection.
2Adaptability or versatility
If a narrow spectral range is used for measurement, then the measurement method is straightforward, but the applicability and dynamic range are restricted
Solution Approach 1:
The patent creates a universal measurement system that can handle multiple gas components (methane, CO2, H2S) and varying compositions by incorporating multiple spectroscopic envelopes. Each envelope is designed to be sensitive to specific absorption bands of different components. The system universally applies to various crude oil samples with different gas contents by selecting appropriate envelope combinations, making the measurement method adaptable rather than component-specific.
Solution Approach 2:
The patent extends the measurement from a single spectral dimension to multiple spectral dimensions by using envelopes across different wavelength ranges (e.g., 1620-1700 nm and 2100-2300 nm). This multi-dimensional spectral approach allows simultaneous detection of multiple components that have distinct absorption characteristics in different spectral regions, greatly enhancing the dynamic range and applicability without proportionally increasing system complexity.
3Reliability
If multiple spectroscopic envelopes are used, then the measurement accuracy and dynamic range improve, but the system complexity increases
Solution Approach 1:
The patent segments the complex measurement task into multiple manageable spectroscopic envelopes, each optimized for specific absorption bands. This segmentation allows the system to achieve high reliability across varying gas compositions by selectively measuring in spectral regions where target components have strong, distinct absorption features, while keeping each individual envelope's design relatively simple and modular.
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 provides a more accurate and reliable measurement of GOR by averaging concentration values from multiple spectroscopic envelopes, reducing noise sensitivity and maintaining linearity across a broader dynamic range, thus overcoming limitations of existing methods.
Implementation Method 1
measuring throughput light from the sample with a photo-detector
Implementation Method 2
NIR absorption spectroscopy has been used to estimate the GOR
Implementation Method 3
Two absorption bands have been detected for CH4, one centered at 1670 nm, and one centered at 1682 nm
Data Source
AI summary
A method of using spectroscopic envelopes for determining components in a sample may include selecting spectroscopic envelopes and passing input light through a sample comprising at least one absorbing component is provided. The method includes measuring throughput light with a photo-detector and determining the concentration of the at least one absorbing component in the sample using the measured throughput, wherein at least one of the plurality of spectroscopic envelopes overlaps at least one absorption band of the at least one absorbing component in the sample. An apparatus for determining components in a sample including an input light source having a spectrum and a sample container having a fixed optical path-length is also provided. The apparatus may include a plurality of pre-selected spectroscopic envelopes to select spectral portions of the throughput light from the sample; and at least one photo-detector to measure the throughput light selected by the spectroscopic envelopes.