Systems and methods to place a thermally conductive sheath in a geothermal well
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Solution Overview
Problem
Existing geothermal well systems face inefficiencies in thermal energy transfer from the target zone to the heat harvester, particularly due to limitations in thermal conductivity within the wellbore, which hampers the effective coupling of the target formation to the heat harvester.
Innovation Solution
A multi-segmented thermally conductive sheath, known as the Thermal Reach Enhancement (TRE) sheath, is placed in the wellbore using a staged process involving pumping, settling, and consolidating a mixture of thermally conductive particles and a carrier fluid, followed by removing the carrier fluid, to form a compacted sheath with high thermal conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If conventional wellbore systems are used without thermally conductive enhancement, then the system structure remains simple, but thermal energy transfer efficiency from target zone to heat harvester is poor
Solution Approach 1:
The patent changes the thermal conductivity parameter of the wellbore system by introducing thermally conductive particles (such as metal particles, graphite, or diamond) into the carrier fluid mixture. This transforms the thermal properties of the wellbore medium, enabling efficient thermal energy transfer from the target formation to the heat harvester while maintaining a relatively simple overall system structure.
Solution Approach 2:
The patent creates a composite material system by combining thermally conductive particles with a carrier fluid to form a pumpable slurry. This composite mixture is then placed in the annular space of the wellbore, creating a composite thermal conduction path that enhances heat transfer efficiency without requiring complete system redesign.
2Reliability
If multi-stage pumping and consolidation process is used to place TRE sheath, then thermal conductivity of wellbore is significantly improved, but the placement process becomes more complex and time-consuming
Solution Approach 1:
The patent divides the wellbore treatment into multiple stages, with each stage involving pumping a portion of the TRE mixture, allowing it to settle, and then consolidating it. This segmentation enables controlled placement of the thermally conductive sheath in manageable sections, ensuring proper consolidation and thermal conductivity at each stage while maintaining overall process control.
Solution Approach 2:
The patent performs preliminary actions by first pumping the carrier fluid to prepare the annular space, then introducing thermally conductive particles, and allowing settling before consolidation. These preliminary steps ensure proper positioning and distribution of materials before final consolidation, thereby guaranteeing the desired thermal conductivity and structural integrity of the sheath.
3Ease of operation
If thermally conductive particles are suspended in carrier fluid for pumping, then the mixture becomes pumpable and placeable, but the presence of carrier fluid reduces the effective thermal conductivity of the final sheath
Solution Approach 1:
The patent extracts or removes the carrier fluid from the mixture after the thermally conductive particles have been properly positioned and settled in the annular space. This extraction process leaves behind a concentrated assembly of thermally conductive particles forming the sheath, thereby eliminating the thermal resistance introduced by the carrier fluid while maintaining the pumpability advantage during the placement phase.
Solution Approach 2:
The patent uses the carrier fluid as an intermediary medium that facilitates the pumping and placement of thermally conductive particles. The carrier fluid enables easy transport of particles to the target location, then serves as a temporary placeholder that is subsequently removed. This intermediary approach allows the system to benefit from both pumpability during installation and high thermal conductivity in the final structure.
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 TRE sheath significantly enhances thermal conductivity within the wellbore, allowing for more efficient transfer of thermal energy from the target formation to the heat harvester, thereby improving geothermal energy recovery and production efficiency.
Implementation Method 1
settling the TRE particles in the annular space of the wellbore
Implementation Method 2
The TRE sheath significantly enhances thermal conductivity within the wellbore, allowing for more efficient transfer of thermal energy from the target formation to the heat harvester
Data Source
AI summary
Various systems and methods are presented for placing a multi-segmented thermally conductive sheath around a closed-loop heat harvesting system in of a geothermal well for purposes of improved electrical or thermal energy generation and recovery. The systems and methods presented herein additionally allow for a more efficient means of installing a thermally conductive sheath at the extreme depths and temperatures of typical geothermal well target locations.