Downhole Tool Cooling via Pre-cooled Solid Cold Source
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Solution Overview
Problem
Existing cooling systems for downhole tools in oil and gas exploration, such as Peltier elements and Stirling engines, face inefficiencies and reliability issues when operating in high-temperature environments, leading to impractical power consumption and reduced performance.
Innovation Solution
A downhole tool cooling device utilizing a rechargeable solid cold source contained in an insulated vessel, thermally coupled to the tool via a cooling circuit with heat exchangers, and a refrigeration system that can be charged pre-operatively and adapted during operations, using a Stirling machine or liquid nitrogen circulation for efficient cooling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If Peltier elements are used to cool downhole tools in high-temperature environments, then temperature difference can be achieved, but power consumption becomes impractically high
Solution Approach 1:
The patent pre-cools a thermal mass (solid cold source) before deployment to the wellsite. This thermal mass is cooled using surface-based refrigeration systems and then sealed in an insulated vessel, allowing it to provide cooling during downhole operations without requiring continuous high power consumption Peltier elements.
Solution Approach 2:
The patent introduces a thermal mass as an intermediary between the power source and the device to be cooled. This thermal mass stores cooling capacity in advance and releases it during operation, decoupling the continuous power requirement from the cooling function and enabling use with limited power supply.
2Temperature
If standard refrigeration systems are used for cooling, then cooling capacity can be achieved, but system complexity and reliability are reduced due to multiple moving parts
Solution Approach 1:
The patent extracts the refrigeration system from the downhole environment and places it on the surface. Only a simple thermal mass storage vessel is deployed in the well, eliminating complex compressors, condensers, and expansion devices from the downhole environment where they would add complexity and reduce reliability.
Solution Approach 2:
The patent uses a simple, robust thermal mass vessel that can be easily replaced if needed, rather than attempting to make the refrigeration system itself disposable. The vessel contains pre-cooled thermal mass that provides cooling for the duration of the operation, then can be replaced with a fresh pre-cooled vessel.
3Temperature
If refrigeration systems operate in hot environments, then cooling can be provided, but efficiency decreases due to convection limitations
Solution Approach 1:
The thermal mass is pre-cooled to the required temperature before being sealed in the insulated vessel and deployed to the wellsite. This preliminary cooling action allows the thermal mass to provide efficient cooling during operation without relying on continuous convection heat transfer, which is inefficient in hot environments.
Solution Approach 2:
The insulated vessel maintains the cooling capacity of the thermal mass continuously during downhole operations, providing uninterrupted cooling without relying on periodic convection cycles. The thermal mass continuously releases stored cooling capacity as long as the insulation maintains the temperature differential.
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 solution provides effective and efficient cooling for downhole tools by maintaining a stable operating temperature, reducing power consumption, and enhancing reliability through adaptive cooling and insulation, even in extreme environments.
Implementation Method 1
a cooling circuit comprising a first heat exchanger arranged at the downhole tool and in a fluid communicating manner being interconnected with a second heat exchanger arranged in the solid cold source body
Implementation Method 2
a rechargeable cold source comprising a solid cold source body being contained in an insulated cooling medium vessel
Data Source
AI summary
A downhole tool cooling device (2) is described, wherein a downhole tool (1) is thermally coupled to a rechargeable cold source (21) comprising a solid cold source body (211) being contained in an insulated cooling medium vessel (22), and wherein the downhole tool (1) is thermally coupled to the cold source (21) by means of a cooling circuit (23) comprising a first heat exchanger (11) arranged at the downhole tool (1) and in a fluid communicating manner being interconnected with a second heat exchanger (231) arranged in the solid cold source body (211), wherein a refrigeration system (5) is thermally coupled to the cold source (21) during a downhole operation of the cooling device (2). Furthermore is described a method for cooling a downhole tool (1). Also is described use of a pre-cooled solid cold source body (211) contained in an insulated cooling medium vessel (22) as a cold source (21) for a cooling circuit (23) being thermally coupled to a downhole tool (1) being in the need of cooling during downhole operations.