System and method for quantifying thermal conductivity of subsurface formations for geothermal energy systems
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing geothermal energy systems are limited by the need for specific geological locations and lack a systematic method to quantify thermal conductivity of subsurface formations, which affects heat transfer efficiency in Advanced Closed Loop (ACL) systems.
Innovation Solution
A method to quantify thermal conductivity by integrating well log and rock sample interpretations using anisotropic equivalent media mixing laws, allowing for real-time estimation and upscaling of thermal conductivity along wellbores and the subsurface formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional geothermal systems are used, then heat transfer efficiency is improved through natural fractures, but deployment location is limited to specific geological areas
Solution Approach 1:
The patent inverts the traditional approach by instead of relying on natural fractures to enable heat transfer, it creates an artificial closed-loop system where fluid circulates through drilled wellbores to extract heat conductively from hot rock formations. This allows geothermal energy extraction in locations without natural fractures by reversing the dependency relationship.
Solution Approach 2:
The patent changes the thermal conductivity parameter of the subsurface formation by selecting and targeting formations with sufficiently high thermal conductivity values (typically greater than 2.0 W/m·K). This parameter selection enables effective heat transfer in the closed-loop system, allowing deployment in broader geological locations that meet this thermal conductivity criterion rather than requiring specific fracture patterns.
2Measurement precision
If thermal conductivity quantification methods are developed, then assessment accuracy for ACL systems is improved, but measurement and analysis complexity increases
Solution Approach 1:
The patent segments the thermal conductivity assessment into distinct components: well log analysis to evaluate formation properties along the wellbore, rock sample analysis to measure actual thermal conductivity values, and integration of these data sources. This segmentation allows systematic quantification of thermal conductivity while managing complexity through structured analysis steps.
Solution Approach 2:
The patent uses an intermediary approach by employing well logs as a mediator between direct thermal conductivity measurement and formation assessment. Well logs provide continuous formation property data that can be correlated with thermal conductivity, serving as an intermediate tool that simplifies the overall measurement process while maintaining assessment accuracy.
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
Enables accurate assessment of subsurface formations for ACL systems, optimizing well path design and heat transfer efficiency, thereby enhancing geothermal energy production.
Implementation Method 1
heat transfer occurs conductively from hot rocks to the working fluid in the wellbores
Data Source
AI summary
A method is described for assessing subsurface formations for their suitability for use as an advanced close loop geothermal energy system by quantifying thermal conductivity of the subsurface formations. The thermal conductivity is quantified by obtaining rock samples and well logs from a well; analyzing the well logs to generate a well log interpretation; analyzing the rock samples to generate a rock sample interpretation; integrating the well log interpretation and the rock sample interpretation to generate a combined interpretation; estimating thermal conductivity along the well based on the combined interpretation using anisotropic equivalent media mixing laws; upscaling the thermal conductivity along the well to quantify thermal conductivity for the well as part of an advanced closed loop geothermal system; and quantifying the thermal conductivity of the subsurface formation based on the thermal conductivity for the well as part of an advanced closed loop geothermal system.