RF Antenna Assembly with Slidable Connectors
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Solution Overview
Problem
Current hydrocarbon recovery methods, such as Steam-Assisted Gravity Drainage (SAGD), face challenges including long production times, significant heat loss, excessive steam consumption, high costs, and environmental impact due to water usage, and are not suitable for all geological conditions, while RF heating has installation difficulties and inefficiencies.
Innovation Solution
A hydrocarbon recovery system featuring an RF source and an RF antenna assembly with a dipole configuration, including tubular conductors, a dielectric isolator, and electrical contact sleeves, designed for in-situ assembly within a wellbore to minimize dielectric heating and withstand extreme temperatures and corrosive environments, using a feed structure with radially compressible connectors and insulating coatings for efficient energy transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If traditional SAGD method is used, then hydrocarbon recovery is achieved, but heat loss is significant and steam consumption is excessive
Solution Approach 1:
The patent replaces the mechanical/thermal SAGD system with an electromagnetic RF heating system. RF antennas transmit electromagnetic energy directly to heat the hydrocarbon-bearing formation, eliminating the need for steam injection and associated heat losses. This substitution of heating mechanism directly addresses the contradiction by reducing energy loss while maintaining recovery effectiveness.
Solution Approach 2:
The patent changes the fundamental parameter of heating method from thermal conduction (steam) to electromagnetic radiation (RF). By operating at specific RF frequencies that resonate with the formation properties, the system achieves more efficient energy transfer and reduced heat loss to surrounding formations, thereby improving both energy efficiency and recovery productivity.
2Productivity
If RF antenna assembly is installed in wellbore, then hydrocarbon recovery efficiency is improved, but installation complexity increases
Solution Approach 1:
The RF antenna assembly is divided into modular segments that can be assembled in sections within the wellbore. The antenna elements, feed structure, and isolators are configured as separate but interconnected components, allowing for easier installation and positioning without requiring complete assembly at the surface, thus reducing installation complexity while maintaining system effectiveness.
Solution Approach 2:
The RF antenna elements are nested within the wellbore structure, with the antenna assembly fitting inside the existing well casing. The feed structure and electrical components are nested within the antenna elements, allowing compact installation within the confined wellbore space while maintaining full functional capability for improved hydrocarbon recovery.
3Reliability
If dielectric isolator is used in RF antenna assembly, then arcing is prevented, but device complexity increases
Solution Approach 1:
Dielectric isolators are positioned as intermediary components between the conductive antenna elements and the surrounding environment. These isolators prevent direct contact between conductive parts that could cause arcing, while their placement is optimized to provide maximum insulation with minimum added complexity to the overall antenna assembly structure.
4Reliability
If radial compressible connectors are used, then electrical contact reliability is improved, but manufacturing complexity increases
Solution Approach 1:
The connectors incorporate radially compressible elements that dynamically adjust to maintain optimal electrical contact pressure. This dynamic compression capability ensures reliable electrical connection between antenna elements and feed structure, compensating for manufacturing tolerances and thermal expansion, while the connector design is simplified to achieve this reliability without excessive manufacturing complexity.
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
The system enhances hydrocarbon recovery efficiency by reducing heat loss, minimizing steam consumption, and simplifying installation, while maintaining structural integrity and preventing arcing, thus improving the overall cost-effectiveness and environmental sustainability of the process.
Implementation Method 1
A hydrocarbon recovery system features an RF source and an RF antenna assembly with a dipole configuration... designed for in-situ assembly within a wellbore... efficient energy transmission
Implementation Method 2
The heavy oil is immobile at reservoir temperatures, and therefore, the oil is typically heated to reduce its viscosity... RF heating has installation difficulties and inefficiencies
Implementation Method 3
An RF antenna assembly to be positioned within a wellbore in a subterranean formation for hydrocarbon resource recovery... a dielectric isolator... preventing arcing
Implementation Method 4
a feed structure with radially compressible connectors... maintaining structural integrity
Implementation Method 5
an RF antenna assembly with a dipole configuration, including tubular conductors... first and second tubular conductors define a dipole antenna
Data Source
AI summary
An RF antenna assembly may include first and second tubular conductors, a dielectric isolator, and first and second electrical contact sleeves respectively coupled between the first and second tubular conductors and the dielectric isolator. The RF antenna assembly may include an RF transmission line having an inner conductor and an outer conductor extending within the first tubular conductor, and a feed structure coupled to a distal end of the RF transmission line. The feed structure may include a first radially compressible connector coupled to the outer conductor of the RF transmission line to slidably engage adjacent portions of the first electrical contact sleeve, a second radially compressible connector coupled to the inner conductor of the RF transmission line to slidably engage adjacent portions of the second electrical contact sleeve, and a dielectric tube coupled between the first and second radially compressible connectors.