Coaxial Mode Converters for Uniform RF Heating in Horizontal Wells
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Solution Overview
Problem
Existing RF heating systems for oil wells, such as resonant antennas and triaxial antennas, are ineffective for long horizontal wells due to limited energy distribution and bulkiness, and two-wire line antennas suffer from high energy losses and uncontrollable power distribution, making it difficult to achieve uniform heating over large reservoirs.
Innovation Solution
A device that generates a disturbance in the differential mode of propagation of an RF signal along a coaxial transmission line using mode converters, creating inductive or capacitive elements to induce currents and electromagnetic fields, allowing for uniform and controlled RF radiation distribution along long drain sections, thereby forming a compact and efficient antenna array for heating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If resonant antennas are used for RF heating in oil wells, then heating capability is achieved, but energy distribution is limited and the system becomes ineffective for long horizontal wells
Solution Approach 1:
The patent divides the continuous antenna structure into discrete mode converter segments distributed along the coaxial transmission line. Each segment independently generates electromagnetic disturbances, enabling distributed heating along the entire well length rather than concentrating energy at a single resonant point. This segmentation allows effective heating of long horizontal wells by distributing the heating function across multiple locations.
2Area of stationary object
If triaxial antennas are used for distributed heating, then heating coverage is improved, but the system becomes bulky and complex
Solution Approach 1:
The mode converter is nested within the existing coaxial transmission line structure, with its conductors integrated into the coaxial geometry. The first conductor connects to the external conductor and the second conductor connects to the internal conductor, allowing the heating function to be embedded within the transmission line without adding external bulky structures. This nesting eliminates the need for separate triaxial antenna configurations while achieving distributed heating.
3Device complexity
If two-wire line antennas are used for RF heating, then simplified structure is achieved, but energy losses are high and power distribution is uncontrollable
Solution Approach 1:
The mode converter design allows control of electromagnetic disturbance generation through the connection means that link the conductors to the coaxial transmission line. By adjusting the connection configuration and impedance matching, the power distribution along the transmission line can be controlled to minimize energy losses. The inductive or capacitive elements can be tuned to optimize energy transfer efficiency, providing controllable power distribution unlike the fixed two-wire line configuration.
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 efficient distribution of RF energy over long horizontal wells, providing uniform heating and increasing oil well productivity with reduced energy expenditure, while being less sensitive to geological formations and capable of regulating temperature distribution.
Implementation Method 1
a disturbance in the differential mode of propagation of the signal along the coaxial transmission line is generated, inducing a current in the external conductor of the coaxial transmission line and an electromagnetic field in the area surrounding the coaxial transmission line
Implementation Method 2
creating inductive or capacitive elements to induce currents and electromagnetic fields, allowing for uniform and controlled RF radiation distribution along long drain sections, thereby forming a compact and efficient antenna array for heating
Data Source
AI summary
The present invention relates to a device for generating a disturbance in the differential mode of propagation of an RF signal transmitted along a coaxial transmission line.