Nested Heater Pattern for In Situ Thermal Processing
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Solution Overview
Problem
Current methods for heating subsurface hydrocarbon formations to produce hydrocarbons are inefficient, costly, and result in significant heat loss to the overburden, leading to high energy consumption and environmental concerns, particularly in extracting heavy hydrocarbons from tar sands and oil shale.
Innovation Solution
The implementation of a heater pattern with nested inner and outer zones, where the inner zone has a higher heater density and the outer zone has a lower heater density, allowing for efficient thermal energy migration and extended hydrocarbon fluid production, minimizing the number of required heaters and reducing energy costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If uniform heater density is used throughout the formation, then heating coverage is achieved, but the number of heaters required increases significantly and energy efficiency decreases
Solution Approach 1:
The patent applies local quality by varying heater density across different zones of the formation. The first zone (near the wellbore) has a higher heater density to provide intensive heating where thermal energy is needed most, while the second zone (farther from the wellbore) has a lower heater density. This non-uniform distribution optimizes energy efficiency by concentrating heating capacity where it is most effective and reducing the total number of heaters required compared to a uniform distribution approach.
Solution Approach 2:
The patent segments the formation into multiple zones with different heating requirements. By dividing the formation into a first zone and a second zone with distinct heater densities, the system can independently optimize heating parameters for each zone. This segmentation allows the inner zone to receive intensive heating while the outer zone receives sufficient but less intensive heating, thereby reducing overall energy consumption and the total number of heaters needed.
2Productivity
If high heater density is used throughout the formation, then rapid heating and hydrocarbon production is achieved, but equipment size and cost increase significantly
Solution Approach 1:
The patent implements local quality by applying different heater densities to different spatial zones. The first zone, which is closer to the wellbore and likely has better permeability or lower thermal conductivity, receives a higher heater density to rapidly generate hydrocarbon fluids. The second zone receives a lower heater density, reducing the total number of heaters and associated equipment complexity while still maintaining productive flow through the pressure gradient and thermal energy migration from the first zone.
Solution Approach 2:
The formation is segmented into functional zones with different productivity characteristics. The first zone is designed for rapid hydrocarbon generation with high heater density, while the second zone serves as an extension for fluid collection and production with lower heater density. This segmentation allows the system to achieve high overall productivity without requiring uniformly high heater density throughout, thereby reducing equipment complexity and cost.
3Quantity of substance
If extensive mining is performed to access hydrocarbon formations, then hydrocarbon extraction is enabled, but environmental damage and processing costs increase
Solution Approach 1:
The patent replaces extensive mechanical mining operations with an in situ thermal stimulation approach. Instead of physically removing large volumes of formation material through mining, the system uses heaters deployed in the formation to thermally crack hydrocarbons in place and induce flow through the existing permeability pathways. This substitution of mechanical extraction with thermal-stimulation-based in situ production significantly reduces environmental disturbance, eliminates the need for large-scale surface infrastructure, and lowers processing costs while maintaining effective hydrocarbon recovery.
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 enables a rapid rise in hydrocarbon fluid production in the inner zone, which is sustained over time by thermal energy migration to the outer zone, optimizing energy use and reducing environmental impact by minimizing equipment size and emissions.
Implementation Method 1
a first heater that is an electrical heater
Implementation Method 2
sustained over time by thermal energy migration to the outer zone
Implementation Method 3
in situ thermal processing
Data Source
AI summary
Embodiments of the present invention relate to heater patterns and related methods of producing hydrocarbon fluids from a subsurface hydrocarbon-containing formation (for example, an oil shale formation) where a heater cell may be divided into nested inner and outer zones. Production wells may be located within one or both zones. In the smaller inner zone, heaters may be arranged at a relatively high spatial density while in the larger surrounding outer zone, a heater spatial density may be significantly lower. Due to the higher heater density, a rate of temperature increase in the smaller inner zone of the subsurface exceeds that of the larger outer zone, and a rate of hydrocarbon fluid production ramps up faster in the inner zone than in the outer zone. In some embodiments, a ratio between a half-maximum sustained production time and a half-maximum rise time of a hydrocarbon fluid production function is relatively large.