Common Mode Choke Assembly for RF Heating Wellbore Systems
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Solution Overview
Problem
Current hydrocarbon recovery methods, such as Steam-Assisted Gravity Drainage (SAGD), face issues like long production times, significant heat loss, excessive steam consumption, high costs, and environmental impact due to water usage, and inefficiencies in RF heating systems caused by impedance mismatches and high power requirements.
Innovation Solution
A system comprising a radio frequency (RF) antenna positioned within a wellbore, a coaxial transmission line, and a common mode choke assembly with ring-shaped choke cores and a sleeve for cooling fluid circulation, designed to minimize current induction and maintain efficient heating while reducing heat dissipation and power losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If RF heating is used to heat hydrocarbons, then heating efficiency is improved, but impedance mismatches cause power losses and heat dissipation
Solution Approach 1:
A common mode choke assembly is introduced as an intermediary component between the RF source and transmission line. The choke assembly suppresses common mode currents that cause impedance mismatches and energy losses, thereby reducing power losses while maintaining heating efficiency. The choke acts as a mediator to eliminate harmful electromagnetic interference without affecting the useful RF heating function.
2Power
If high power RF heating is applied, then heating effectiveness is improved, but heat dissipation and steam consumption increase
Solution Approach 1:
The common mode choke assembly converts harmful common mode currents into beneficial effect by suppressing them. The choke transforms the harmful electromagnetic interference and energy dissipation into controlled impedance matching, thereby reducing steam consumption and heat loss while maintaining high heating effectiveness. The harmful energy that would otherwise be lost is now efficiently coupled into the hydrocarbon formation.
3Productivity
If conventional SAGD method is used, then hydrocarbon recovery is achieved, but production time is extended and heat loss occurs
Solution Approach 1:
The patent replaces the conventional thermal steam injection system with an RF electromagnetic heating system. This substitution eliminates the need for extensive steam generation and injection infrastructure, directly heating the hydrocarbons through electromagnetic induction. The RF heating method achieves faster heating rates and shorter production times compared to traditional SAGD, while reducing heat loss through the formation.
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 maintaining effective heating within the target area, while also addressing the inefficiencies and high power issues in RF heating systems.
Implementation Method 1
a radio frequency (RF) antenna configured to be positioned within the wellbore, an RF source, and a transmission line coupled between the RF antenna and the RF source
Implementation Method 2
The frequency of the microwaves is at a frequency substantially equivalent to the resonant frequency of the water so that the water is heated
Implementation Method 3
A plurality of ring-shaped choke cores may surround the transmission line
Implementation Method 4
a sleeve may surround the plurality of ring-shaped choke cores and define a cooling fluid path for the plurality of ring-shaped choke cores
Data Source
AI summary
A system for heating a hydrocarbon resource in a subterranean formation having a wellbore extending therein may include a radio frequency (RF) antenna configured to be positioned within the wellbore, an RF source, a cooling fluid source, and a transmission line coupled between the RF antenna and the RF source. A plurality of ring-shaped choke cores may surround the transmission line, and a sleeve may surround the ring-shaped choke cores and define a cooling fluid path for the ring-shaped choke cores and in fluid communication with the cooling fluid source.