Drilling Fluid Gas Detection Using 3.1-3.6 μm Infrared Absorption
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current gas detection systems for drilling fluids, particularly those using thermal conductivity detectors (TCDs), face issues such as inability to differentiate between hydrocarbon gases, sensitivity to moisture and particles, limited durability, temperature dependence, and false positives from hydrogen sulphide, nitrogen, and carbon dioxide, making them unreliable and cumbersome.
Innovation Solution
A method and apparatus utilizing a specific range of the infra-red spectrum (3.1-3.6 μm) to detect light and heavy hydrocarbons in drilling fluids, employing a pyroelectric detector and filtering to isolate absorption spectra, which is less affected by interfering gases and temperature variations, and includes a cyclical IR emitter and reference channel for temperature compensation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If thermal conductivity detectors (TCDs) are used for gas detection, then the apparatus can detect total gas content, but it cannot differentiate between hydrocarbon gases and other gases such as hydrogen sulphide, nitrogen and carbon dioxide
Solution Approach 1:
The patent segments the gas detection process by using multiple detectors, each tuned to detect specific hydrocarbon constituents (methane, ethane, propane, butane, pentane) at different wavelengths. This segmentation allows differentiation between various gas types and eliminates false positives from non-hydrocarbon gases.
Solution Approach 2:
The patent applies local quality by using absorptive filters with specific wavelength characteristics for each detector. Each detector is optimized with a filter that passes only the wavelength range characteristic of the target hydrocarbon, enabling selective detection and differentiation of gas components.
2Reliability
If TCDs are used for gas detection, then the apparatus can provide total gas indication, but the detector reacts with hydrocarbon gases and moisture causing corrosion and reduced durability
Solution Approach 1:
The patent replaces the thermal conductivity detection mechanism with infrared absorption detection. This substitution eliminates the chemical reaction and corrosion issues inherent in TCDs, as the infrared detectors measure gas composition through light absorption without physical or chemical contact with the sample gas.
3Measurement precision
If TCDs are used for gas detection, then the apparatus can detect gas content, but temperature variations cause zero drift and inaccurate results
Solution Approach 1:
The patent incorporates temperature compensation mechanisms that monitor temperature variations and adjust the detection baseline accordingly. This feedback system eliminates zero drift caused by temperature changes, maintaining measurement accuracy across varying environmental conditions.
4Measurement precision
If infrared sources with higher power are used to increase detection sensitivity, then the detection range is improved, but the apparatus generates more heat that interferes with the detector and requires higher power and size
Solution Approach 1:
The patent uses absorptive filters with specific wavelength characteristics for each detector. Each detector is optimized with a filter that passes only the wavelength range characteristic of the target hydrocarbon, enabling selective detection and differentiation of gas components.
5Measurement precision
If TCDs are used for gas detection, then the apparatus can provide gas analysis, but it is sensitive to hydrogen sulphide, nitrogen and carbon dioxide resulting in false positives
Solution Approach 1:
The patent segments the gas detection process by using multiple detectors, each tuned to detect specific hydrocarbon constituents (methane, ethane, propane, butane, pentane) at different wavelengths. This segmentation allows differentiation between various gas types and eliminates false positives from non-hydrocarbon gases.
Solution Approach 2:
The patent applies local quality by using absorptive filters with specific wavelength characteristics for each detector. Each detector is optimized with a filter that passes only the wavelength range characteristic of the target hydrocarbon, enabling selective detection and differentiation of gas components.
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 allows for accurate and reliable differentiation between light and heavy hydrocarbons, providing a stable and portable solution that reduces maintenance needs and improves sensitivity and durability, while minimizing interference from hydrogen sulphide, nitrogen, and carbon dioxide.
Implementation Method 1
employing a pyroelectric detector and filtering to isolate absorption spectra
Implementation Method 2
transmitting infra-red radiation through said gas and detecting with a detector infra-red radiation that has passed through said gas
Data Source
AI summary
A method of detecting gas conveyed in a drilling fluid (M) returning from a well (26), which method comprises the steps of:(a) extracting gas from said drilling fluid (M);(b) transmitting infra-red radiation through said gas; and(c) detecting with a detector (50) infra-red red radiation that has passed through said gas and providing an output signal representative thereof;characterised by the step of:(d) examining the intensity of a portion of the infra-red spectrum within a range of approximately 3.1 μm and 3.6 μm to estimate whether or not said gas comprises any light or heavy hydrocarbons.