Sub-surface Energy and Storage
“Subsurface energy and storage” refers to the practice of storing energy within underground geological formations, like depleted oil and gas reservoirs, aquifers, or deep saline formations, utilizing the Earth’s subsurface as a storage medium for various forms of energy, including heat (geothermal), compressed air, hydrogen, or carbon dioxide, allowing for energy to be captured and accessed when needed.
Key aspects of subsurface energy storage:
Applications
- Geothermal energy: Storing heat extracted from the Earth’s subsurface for later use.
- Carbon capture and storage (CCS): Injecting captured carbon dioxide underground to prevent its release into the atmosphere.
- Compressed air energy storage (CAES): Storing compressed air in underground caverns to generate electricity when needed.
- Hydrogen storage: Storing hydrogen underground for future use in fuel cells.
Benefits
- Large storage capacity: The Earth’s subsurface offers vast storage potential compared to surface-based options.
- Long-duration storage: Energy can be stored underground for extended periods, enabling seasonal energy management.
- Potential for renewable energy integration: Can help balance fluctuations in renewable energy sources like solar and wind.
Challenges
- Geological characterization: Understanding the subsurface geology to identify suitable storage sites.
- Injection and extraction technologies: Developing efficient methods to inject and retrieve stored energy.
- Environmental considerations: Ensuring the safety and long-term integrity of storage sites, including potential impacts on groundwater.
Geothermal Energy Data and Potential
As a contributing partner of a national coalition, the Michigan Geological Repository for Research and Education at Western Michigan University has been collecting data from across the state that will aid industry in the identification and development of geothermal energy, and it has integrated that data into the National Geothermal Data System. These data are available to all those interested in developing geothermal energy resources.
The National Geothermal Data System is a distributed data system providing access to information resources related to geothermal energy from a network of data providers. Data are contributed by academic researchers, private industry and state and federal agencies. Funded by the Department of Energy’s Geothermal Technology Office, the NGDS provides information to help accelerate the development of United States geothermal resources and can be used to:
- Assess geothermal potential.
- Help potential investors evaluate potential income, expenses and long-term cash flow.
- Reduce risks in exploration and development of this energy source.
- Guide land-use planners and governmental agencies in making decisions about community development.
Geothermal Energy Potential for Michigan
Dr. William B. Harrison, III, research director, had led efforts to assess Michigan’s geothermal energy potential. Unlike western states with easily accessible geothermal resources like geysers, Michigan’s geothermal energy comes from hot brines in deep rock formations. Harrison gathered data from deep wells drilled by oil and gas companies, focusing on temperature and pressure records, as well as water chemistry and lithology information.
Research focused on shallow formations to evaluate heat flow for geothermal heat exchange systems, which are already widely used in Michigan for heating and cooling. Michigan’s low geothermal gradient means high-temperature geothermal power generation is challenging, requiring depths over 10,000 feet. However, shallow geothermal systems can still offer economic benefits.
Other states are exploring the use of existing deep wells for geothermal energy, and Harrison suggests that Michigan might have similar potential, but more data is needed to identify the locations of hot brine fluids. Compiling geothermal data from across the U.S. is crucial for developing this renewable energy resource.
Increasing Domestic Oil and Gas Recovery
At Western Michigan University’s Michigan Geological Repository for Research and Education (MGRRE), faculty and students are conducting groundbreaking research that has significantly boosted domestic oil and gas production. The Michigan Basin, a key hydrocarbon source in the U.S., has produced about 1.3 billion barrels of oil and 5.9 trillion cubic feet of natural gas over the past 75 years. However, production has declined as known fields deplete.
MGRRE archives and digitizes analytical, pressure, and production data from oil and gas wells, combining it with cores and well records. Using different software, they are improving understanding of underground reservoirs, helping to increase production from existing fields rather than seeking new sources. This research offers several benefits, including:
- More cost-efficient oil and gas recovery.
- Increased productivity for small companies.
- Job creation and higher revenue for property owners.
- More state royalties, supporting recreational areas through the Michigan Natural Resources Trust Fund.
- Reduced environmental impact with fewer drilling operations.
- Lower reliance on foreign oil.
- Hands-on training for future geoscientists and better resource management.
MGRRE’s work helps increase hydrocarbon recovery, benefits the economy, and contributes to sustainable resource use.
Oil Recovery and CO2 Sequestration
Research Partnership to Secure Energy for America
The Michigan Geological Repository for Research and Education at Western Michigan University, as part of the Research Partnership to Secure Energy for America’s Small Producer Program, has been conducting research to extend the life of mature fields in an environmentally sustainable way. The term “small producer” is defined in the 2005 Energy Policy Act as “an entity organized under the laws of the United States with production levels of less than 1,000 barrels per day of oil equivalent.”
The Small Producer Program was established to benefit small producing companies in technology development for mature oil and gas fields, with the objective of extending the life and ultimate recovery of these fields. This is an important group to overall United States production. MGRRE’s research in the Michigan Basin deals with facies analyses and modeling which can also be used in other mature basins.
Hydrothermal Dolomite Reservoirs
Some of the most productive hydrocarbon formations in the Michigan Basin are characterized as hydrothermal dolomite.
At the Michigan Geological Repository for Research and Education at Western Michigan University, we conducted research for two years through the Research Partnership to Secure Energy for America program to find out more about the differences between the productive and non-productive formations.
In the Niagaran (Silurian), we saw a general trend of increasing dolomitization shelfward, with limestone predominant in more basinward positions. One of our major findings was that these facies types are directly related to reservoir porosity and permeability in these dolomites, which increases the predictability of reservoir quality in these units. This pattern is consistent with our original hypothesis of primary facies control on dolomitization and resulting reservoir quality at some level. The identification of distinct and predictable vertical stacking patterns within a hierarchical sequence and cycle framework provides a high degree of confidence at this point that the results should be exportable throughout the basin. Data was derived from detailed analysis of cores archived at MGRRE.
