Advanced Geophysical and Hydrophysical Technologies for Fractured Bedrock Characterization: A Brief Summary of Recent Developments

摘要

The last ten years have shown an explosion in the development of subsurface technologies specifically oriented for hydrogeological characterization (non-petroleum). Some petroleum technologies have been successful in the bedrock regime but generally with limited returns and higher cost than hydrogeologic projects can support. This deficit in need versus affordable capability has created an environment conducive to the development of technologies for characterizing the fractured bedrock environment. This development can be divided into two general areas: those borehole geophysical methods related to petrography, lithology, structure, fractures, mineralogy and radiography; and, hydrophysical methods which are related to the direct identification of water bearing intervals (conductors), quantification of advective flow rates in both vertical and horizontal flow regimes, horizontal flow direction, and medium to large scale characterization of inter-borehole hydraulic connections through cross hole testing. Furthermore, the coupling of these geophysical and hydrophysical methods with traditional and advanced hydraulic testing (straddle packer, single and multiple well pump tests) has contributed to a dramatic increase in the level of understanding of the fractured bedrock environment. The integration of geophysical, hydrophysical and hydraulic data has also been advanced due to major improvements in computer hardware and software capabilities. The ability to visualize different data sets and present these data in a manner that directly contributes to project objectives has improved dramatically over the past ten years. In addition to technical achievements, another area of significant improvement has been the ability to provide these technologies in a cost-effective manner. The availability of these state-of-the-art, yet economically accessible, technologies has resulted in their application and benefit for small to large-scale projects. Possibly the most challenging aspect for the future will be educating and training professionals on the advantages and applicability of these advanced technologies in the daily efforts to clean and protect our environment.