Geothermal Drilling Layout With Acute-Angle Drain Connections
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Solution Overview
Problem
Existing drilling architectures for geothermal installations are difficult and expensive due to the complexity of drilling at inclined angles, requiring high accuracy and prone to tool damage, especially with bends and a single point of convergence, which complicates drilling and increases costs.
Innovation Solution
A drilling architecture with acute angles and a concave lateral shaft design, using a rotating steerable drilling tool with real-time guidance, allows for simplified and economical drilling trajectories by minimizing angular deviations and facilitating heat exchange between the heat transfer fluid and the subsoil.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If horizontal drilling is used to reduce surface footprint, then land use efficiency is improved, but drilling complexity and cost increase
Solution Approach 1:
The drilling system is divided into separate functional modules: a drilling unit for creating the horizontal wellbore and a separate injection/production well string system. This segmentation allows the complex horizontal drilling to be handled by specialized equipment while the heat exchange function is handled by a separate modular well string system that can be installed independently.
Solution Approach 2:
A gravel pack is introduced as an intermediary material between the well string and the surrounding subsoil formation. This gravel pack facilitates fluid flow between the well string and the ground water table, enabling efficient thermal exchange without requiring direct contact between the well string and the formation, thereby simplifying the drilling requirements.
2Temperature
If deeper drilling is performed to access groundwater table, then heat exchange efficiency is improved, but drilling cost and difficulty increase
Solution Approach 1:
The system creates a localized heat exchange environment by installing the well string in a horizontal borehole that intersects the groundwater table. Instead of drilling deep vertically to reach the water table, the horizontal borehole creates a local access point that allows the well string to be surrounded by groundwater, providing efficient thermal exchange at a shallower depth.
Solution Approach 2:
The system transitions from vertical drilling to horizontal drilling, changing the dimensional approach from depth-oriented to lateral-oriented access. This dimensional change allows the well string to be positioned within the groundwater table zone through a horizontal borehole, achieving effective heat exchange without the high costs associated with deep vertical drilling.
3Loss of time
If well strings are installed in existing boreholes, then installation time is reduced, but borehole quality and thermal exchange performance may deteriorate
Solution Approach 1:
The system changes the borehole parameters (diameter, shape, quality) to suit the specific thermal exchange requirements. Rather than adapting the well string to existing boreholes, the drilling unit creates optimized boreholes with controlled dimensions and quality characteristics that maximize thermal exchange efficiency while accommodating the well string design.
Solution Approach 2:
The drilling unit performs preliminary action by creating the borehole and installing the gravel pack before the well string is inserted. This preliminary preparation ensures that the borehole has the appropriate quality, size, and surrounding gravel structure to optimize thermal exchange, rather than attempting to install well strings in pre-existing suboptimal boreholes.
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 solution enables efficient heat exchange with simplified and cost-effective drilling, reducing the risk of tool damage and angular deviations, while maintaining a large underground heat exchange surface area.
Implementation Method 1
The ground water table... acts as a heat exchanger between the subsoil and the well strings
Implementation Method 2
The ground water table... acts as a heat exchanger between the subsoil and the well strings
Data Source
Figure 1
Figure 2
Figure 3
AI summary
This layout (12) comprises at least one heat exchange unit (24) comprising: - at least one central well (26) extending from the surface of the subsoil (22); - at least one flank well (28) extending from the surface of the subsoil (22) and having an inclined lateral portion (48); - at least two separate drains (30) connecting the central well (26) and the inclined lateral portion (48) of the flank well (28). For the or each heat exchange unit (24), the central well (26), the flank well (28) and each drain (30) are set out in the one same vertical plane, the intersections between the drains (30) and the central well (26) and between the drains and the inclined lateral portion (48) being separated from one another and the drains (30) opening inclined by an angle less than 45° with respect to the inclined lateral portion (48).