Downhole Cooling Sub for Thermal Management in Drilling Tools
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Solution Overview
Problem
Downhole drilling tools face overheating issues due to high temperatures in deep earth formations, leading to component failure and reduced lifespan, as existing systems are unable to effectively manage thermal stress within the drilling environment.
Innovation Solution
A downhole drilling system incorporating a cooling sub with temperature sensors and a controller to release cooling agents like liquid nitrogen or dry ice, or dissolvable cooling shuttles, and drill pipes with cooling channels to maintain electronic components within safe operational temperature ranges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If drilling is performed in deep earth formations, then drilling depth and exploration capability are improved, but temperature increases causing overheating of electronic components
Solution Approach 1:
The patent introduces cooling agents (liquid nitrogen, dry ice, or chilled drilling mud) as intermediary substances to transfer heat away from electronic components. These cooling agents act as mediators between the hot formation environment and the sensitive electronic components, absorbing excess heat and maintaining operational temperatures.
Solution Approach 2:
The patent extracts heat from the electronic components by introducing separate cooling systems. The cooling agents are introduced into the drill string or applied directly to the BHA, extracting thermal energy from the electronic components and removing it through the cooling agent circulation or phase change processes.
2Reliability
If cooling systems are added to reduce temperature, then electronic component reliability is improved, but device complexity increases
Solution Approach 1:
The patent makes the drilling mud serve multiple functions: it acts as both the drilling fluid for cutting removal and as a cooling agent for electronic components. The chilled drilling mud system uses the existing mud circulation infrastructure to provide cooling, eliminating the need for separate cooling fluid systems and reducing overall complexity.
Solution Approach 2:
The cooling system utilizes the existing drilling mud circulation infrastructure to provide cooling functionality. The mud pump and return line system, already present for drilling operations, are leveraged to transport the chilled drilling mud through the drill string and back to the surface, making the cooling system self-servicing without requiring additional independent circulation systems.
3Temperature
If cooling agents are released to reduce temperature, then overheating effects are reduced, but loss of cooling agent substance increases
Solution Approach 1:
The patent utilizes phase transitions of cooling agents (liquid nitrogen evaporating to gas, dry ice sublimating to CO2 gas, chilled drilling mud warming and circulating back) to absorb large amounts of heat during the phase change process. This latent heat absorption provides efficient cooling while the cooling agents are continuously circulated or regenerated, reducing the need for continuous replenishment.
Solution Approach 2:
The chilled drilling mud system establishes continuous circulation of the cooling agent through the drill string and back to the surface for re-chilling. This continuous circulation maintains steady-state cooling without requiring periodic addition of cooling agents, as the same cooling agent is repeatedly used in a closed-loop system.
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 effectively reduces overheating, enhancing the reliability and performance of downhole drilling tools by maintaining electronic components within safe temperature limits, thereby extending their useful life and preventing failures.
Implementation Method 1
The cooling agent can be liquid nitrogen or dry ice (i.e., solid carbon dioxide)... when the temperature sensor detects a temperature of the tool reach a preset temperature
Implementation Method 2
The cooling sub has a temperature sensor, and the cooling agent is released from the each of the tanks when the temperature sensor detects a temperature of the tool reach a preset temperature
Data Source
AI summary
A downhole drilling system for reducing effects of overheating comprises a drill string having one or more drill pipes interconnected therebetween, a bottom hole assembly (BHA) connected to a distal end of the drill string, and a controller. The BHA comprises a drill bit disposed at an end portion of the BHA, a downhole motor to rotate the drill bit, a drill collar, in which a centrally disposed passage is formed and drilling mud is supplied to the drill bit through the centrally disposed passage, a measurement instrument disposed in the drill collar to obtain drilling environmental profile and communicating with the controller, and a cooling sub disposed in or on the drill collar or the measurement instrument.