Modular RF Transmission Line for Downhole Hydrocarbon Recovery
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Solution Overview
Problem
Existing RF transmission lines for hydrocarbon resource recovery in subterranean formations are not designed to withstand high structural loads and stresses, requiring bulky designs with multiple fasteners and limited flexibility, which complicates assembly and increases costs.
Innovation Solution
A high-strength RF transmission line design featuring end-to-end coupled sections with inner and outer conductors surrounded by load-carrying tubular members, using sliding electrical couplers and mechanical couplers for secure connections, allowing for efficient stress distribution and reduced thermal and structural loads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If rigid coaxial sections are coupled together in end-to-end relation for hydrocarbon resource recovery, then the transmission line can deliver RF power to subterranean formations, but the transmission line becomes bulky and requires multiple fasteners increasing assembly complexity
Solution Approach 1:
The transmission line is divided into modular sections that can be coupled together in end-to-end relation. Each section includes conductors within a protective tubular structure, allowing standardized coupling assemblies to join multiple sections efficiently while maintaining structural integrity throughout the long transmission run
Solution Approach 2:
Multiple functional elements are merged into integrated components. The coupling assembly combines electrical connection features, mechanical attachment means, and alignment structures into a single integrated unit that simultaneously performs multiple functions, reducing the number of separate fasteners and assembly steps required
2Reliability
If commercial rigid coaxial designs are used for downhole applications, then RF power can be transmitted, but the transmission line cannot withstand the high tensile loads of 150,000 to 500,000 lbs required in subterranean formations
Solution Approach 1:
High-strength tubular members are pre-positioned during manufacturing to serve as load-bearing structures. These tubulars are installed in place before final assembly, establishing the structural framework capable of withstanding 150,000 to 500,000 lbs tensile loads before the transmission line is put into service
Solution Approach 2:
The transmission line employs composite construction combining conductive materials for RF transmission with high-strength tubular materials for structural support. This composite approach allows the conductors to be protected within robust tubular structures that provide the necessary load-bearing capacity while maintaining electrical functionality
3Strength
If larger diameter coaxial sections are used to increase strength, then the transmission line can withstand higher loads, but the wellbore diameter and installation requirements increase
Solution Approach 1:
The structural strength is achieved by transitioning from relying on conductor diameter to utilizing the tubular member dimension. The tubulars provide the primary load-bearing cross-section while the conductors remain relatively small, effectively moving the strength function to a different dimensional approach that doesn't increase overall transmission line diameter
4Reliability
If multiple fasteners and connectors are used to assemble coaxial sections, then the joints are secure, but the assembly time and installation costs increase
Solution Approach 1:
The coupling assembly integrates multiple fastening functions into a single unified component that simultaneously provides electrical connection, mechanical attachment, and alignment. This merging eliminates the need for multiple separate fasteners and connectors, securing the joint reliably while dramatically reducing assembly time and installation 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 design enhances the assembly efficiency and structural integrity of RF transmission lines, enabling them to withstand high stresses and reduce installation costs by decoupling thermal and structural stresses from the conductors, allowing for smaller wellbore diameters and reduced complexity.
Implementation Method 1
an RF transmission line extending between the RF source and the RF antenna... to deliver RF power to the hydrocarbon resource
Implementation Method 2
a method of heating a petroleum ore by applying RF energy to a mixture of petroleum ore
Data Source
AI summary
An apparatus for hydrocarbon resource recovery from a subterranean formation includes a radio frequency (RF) source, an RF antenna to be positioned within the subterranean formation to deliver RF power to the hydrocarbon resource within the subterranean formation, and an RF transmission line extending between the RF source and the RF antenna. The RF transmission line may include RF transmission line sections coupled together in end-to-end relation. Each section may include an inner conductor, an outer conductor surrounding the inner conductor, and an outer load-carrying tubular member surrounding the outer conductor. A respective coupling assembly joins ends of adjacent sections together. Each coupling assembly may include an electrical coupler being fixedly connected to first ends of corresponding inner and outer conductors and being slidably connected to opposing second ends of adjacent inner and outer conductors, and a mechanical coupler connecting ends of adjacent load-bearing tubular members together.