Fluorescence API Gravity Measurement for Hydrocarbon Fluids
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Solution Overview
Problem
Current methods for characterizing hydrocarbon fluids, such as determining API gravity, require sending samples to off-site laboratories, which is time-consuming and difficult, especially for remote work sites.
Innovation Solution
A fluorescence-based system that applies light pulses at different angles of incidence to measure fluorescence emission intensities over specific time intervals, calculating intensity ratios to determine the API gravity of hydrocarbon fluids directly in the field using a portable apparatus.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If hydrocarbon fluid samples are sent to off-site laboratories for analysis, then accurate characterization of API gravity can be achieved, but time consumption and operational difficulty increase significantly
Solution Approach 1:
The patent introduces fluorescence emission intensity as an intermediary measurement that correlates with API gravity. Instead of directly measuring complex fluid properties in the field, the system uses fluorescence intensity ratios (which can be measured portably) as a mediator that corresponds to API gravity values obtained from laboratory analysis. This intermediary enables accurate API gravity determination without physical sample transport.
Solution Approach 2:
The patent replaces the mechanical/physical system of sample transport and laboratory analysis with an optical measurement system. A portable fluorescence spectrometer uses light emission measurements to determine API gravity, substituting the need for physical sample handling, transportation, and complex laboratory equipment with a field-deployable optical device.
2Measurement precision
If hydrocarbon fluid samples are sent to off-site laboratories for analysis, then accurate characterization of API gravity can be achieved, but operational difficulty increases
Solution Approach 1:
The patent enables the measurement system to perform its own calibration and analysis functions in the field. The portable fluorescence spectrometer with integrated processing capability allows operators to obtain API gravity measurements independently without requiring external laboratory services, sample preparation facilities, or specialized laboratory personnel.
3Measurement precision
If fluorescence emission intensity is measured at multiple time intervals and angles, then API gravity determination accuracy improves, but device complexity increases
Solution Approach 1:
The patent employs periodic light pulses at different time intervals to excite the hydrocarbon fluid and measure fluorescence emission at multiple time points (e.g., 10 nanoseconds, 20 nanoseconds, 30 nanoseconds after pulse initiation). This periodic measurement approach extracts temporal decay characteristics that improve API gravity determination accuracy while using a relatively simple pulsed light source and detector configuration.
Solution Approach 2:
The patent adds the angle of incidence as another measurement dimension. By measuring fluorescence emission intensity at multiple angles (e.g., 0 degrees, 45 degrees, 90 degrees relative to the light pulse direction), the system captures spatial distribution information that enhances measurement accuracy. This multi-dimensional approach (time + angle) improves precision without requiring complex three-dimensional mechanical systems.
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 quick and accurate characterization of hydrocarbon fluids' API gravity at remote locations, reducing the need for laboratory analysis and improving efficiency in field operations.
Implementation Method 1
Some fluids can fluoresce, that is, they give off light when stimulated by a certain wavelength of light from an external source
Implementation Method 2
detecting an intensity of a first fluorescence emission emitted from the sample over a first time interval and a second time interval
Data Source
Figure 1
Figure 2
Figure 3A~3B
AI summary
Methods and systems use fluorescence to determine specific gravity of crude oil samples. A first light pulse (106) is applied to a sample (102) at a first angle-of- incidence. A second light pulse (107) is applied to the sample (102) at a second angle-of-incidence. A first ratio based on the intensity of a first fluorescence emission over a first time interval and the intensity of the first fluorescence emission over a second time interval is calculated. A second ratio based on the intensity of a second fluorescence emission over a third time interval and the intensity of the second fluorescence emission over a fourth time interval is calculated. An intensity ratio based on the first ratio and the second ratio is calculated. A specific gravity of the sample based on the intensity ratio is determined.