Groundwater in Fractured Bedrock Environments: Managing Catchment and Subsurface Resources
Fractured bedrock aquifers have traditionally been regarded as low-productivity aquifers, with only limited relevance to regional groundwater resources. It is now being increasingly recognised that these complex bedrock aquifers can play an important role in catchment management and subsurface energy systems. At shallow to intermediate depth, fractured bedrock aquifers help to sustain surface water baseflows and groundwater dependent ecosystems, provide local groundwater supplies and impact on contaminant transfers on a catchment scale. At greater depths, understanding the properties and groundwater flow regimes of these complex aquifers can be crucial for the successful installation of subsurface energy and storage systems, such as deep geothermal or Aquifer Thermal Energy Storage systems and natural gas or CO2 storage facilities as well as the exploration of natural resources such as conventional/unconventional oil and gas. In many scenarios, a robust understanding of fractured bedrock aquifers is required to assess the nature and extent of connectivity between such engineered subsurface systems at depth and overlying receptors in the shallow subsurface.
Acoustic televiewer amplitude data for porosity estimation with application to porewater conversion
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Published:January 01, 2019
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CiteCitation
J. R. Kennel, B. L. Parker, 2019. "Acoustic televiewer amplitude data for porosity estimation with application to porewater conversion", Groundwater in Fractured Bedrock Environments: Managing Catchment and Subsurface Resources, U. Ofterdinger, A.M. MacDonald, J.-C. Comte, M.E. Young
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Abstract
The ability to detect and quantify rock matrix porosity is explored using acoustic televiewer images and dolostone rock core samples. In particular, an empirical relationship between the acoustic televiewer amplitude response and core-derived total porosity is developed. The performance of the acoustic televiewer amplitude relationship was compared to neutron and gamma-gamma logs, which are traditional nuclear wireline tools commonly used for estimating porosity in dolostones. Acoustic televiewer amplitude results are consistent with the gamma-gamma (density) and neutron (porosity) logs, provide increased vertical resolution, do not require downhole radioactive sources and also provide oriented fracture information. Sample specific porosity and bulk density values from the calibrated acoustic televiewer datasets are then used to improve porewater concentration estimates from rock concentrations.
Supplementary material: Physical properties determined from core samples and predicted from geophysical logs using linear regression are available at: https://doi.org/10.6084/m9.figshare.c.4085918
- acoustical logging
- acoustical methods
- aquifers
- borehole televiewers
- bulk density
- Canada
- carbonate rocks
- concentration
- cores
- data acquisition
- data processing
- density
- dolostone
- Eastern Canada
- equations
- errors
- fractures
- geophysical methods
- ground water
- Guelph Ontario
- Ontario
- pore water
- porosity
- regression analysis
- sedimentary rocks
- statistical analysis
- well-logging
- Wellington County Ontario