HTS Downhole Cable Cooling for Low-Loss Power Transmission
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Solution Overview
Problem
Conventional drilling operations face significant power requirements and thermal management challenges due to poor power conversion efficiencies and heat dissipation in downhole environments, particularly in pulsed power drilling, which exacerbates energy losses and increases operational costs.
Innovation Solution
The use of high temperature superconducting (HTS) cables integrated with coiled tubing for power delivery, combined with cryogenic coolant systems, to minimize heat losses and enable efficient power transmission to downhole tools, eliminating the need for complex power conversion apparatus and allowing high-power pulsed power drilling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If conventional multiconductor cables are used to deliver power downhole, then power can be transmitted to downhole tools, but conduction losses and voltage drops are significant, reducing power delivery efficiency
Solution Approach 1:
The patent applies parameter changes by transitioning from conventional copper cables to high-temperature superconducting (HTS) cables, fundamentally changing the electrical and thermal parameters of the power transmission medium. HTS cables operate at cryogenic temperatures (below -196°C), enabling zero electrical resistance and eliminating I²R conduction losses that plague conventional cables. This parameter change allows efficient transmission of high power (10-600 kW) over long wellbore distances without significant voltage drops.
Solution Approach 2:
The patent employs composite materials by integrating HTS conductors with cryogenic cooling systems, thermal insulation layers, and protective jackets into a unified cable structure. The HTS cable assembly combines superconducting materials (such as YBCO tapes) with stainless steel reinforcement, thermal insulation materials, and cryogenic fluid channels, creating a composite structure that simultaneously achieves zero electrical resistance, thermal management, and mechanical strength required for downhole deployment.
2Productivity
If high power is delivered downhole for pulsed power drilling, then drilling rate increases, but heat dissipation becomes problematic, causing thermal management challenges
Solution Approach 1:
The patent converts the harmful effect of waste heat into a beneficial cooling mechanism. The cryogenic coolant (liquid nitrogen) that is required to maintain HTS cable operation at superconducting temperatures serves dual purposes: it cools the HTS conductors to maintain zero resistance, and simultaneously removes excess heat generated by downhole tools during high-power pulsed drilling operations. This converts the previously problematic heat dissipation issue into a useful thermal management solution.
Solution Approach 2:
The cryogenic coolant system performs multiple functions simultaneously: (1) cooling the HTS cables to maintain superconductivity, (2) removing waste heat from downhole tools, and (3) potentially directly cooling the drill bit or formation during the drilling process. This multi-functionality eliminates the need for separate cooling systems and maximizes the utility of the cryogenic fluid circulation.
3Power
If conventional power conversion apparatus are used downhole, then power can be converted to required levels, but device complexity and power conversion losses increase
Solution Approach 1:
The patent extracts the power conversion function from the downhole environment and relocates it to the surface. By delivering high-voltage, high-current power through HTS cables with zero resistance, the system eliminates the need for complex downhole power conversion equipment such as transformers, rectifiers, and inverters. All power conversion and conditioning is performed at the surface where it is more manageable, and the HTS cable acts as a simple, passive power transmission medium.
Solution Approach 2:
The patent replaces complex mechanical/electrical power conversion systems with a purely electrical transmission solution using HTS cables. Instead of using mechanical transformers or rotating converters downhole, the system uses the unique electrical properties of superconductors to transmit power directly with minimal losses, substituting complex conversion machinery with a sophisticated material property.
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 significantly reduces conduction losses and voltage drops, enabling efficient power delivery up to 1,000 kW and 200 kV to downhole tools, optimizing thermal management and allowing drilling rates of up to 60 feet per hour through hard rock formations without the need for multiple drill bit changes.
Implementation Method 1
high temperature superconducting (HTS) cables integrated with coiled tubing for power delivery
Implementation Method 2
cryogenic coolant systems, to minimize heat losses and enable efficient power transmission
Data Source
AI summary
Systems and methods disclosed herein may comprise a bottom hole assembly; and a cable disposed in the wellbore. In examples, the cable may comprise a superconducting material configured to provide at least power to the bottom hole assembly; one or more liquid supply channels configured to supply a fluid to reduce temperature of the superconducting material; and one or more liquid return channels. Further, cryogenic liquid may be pumped through the liquid supply channels.