Borehole Imaging of In Situ Stress Tests at Mirror Lake Research Site

As part of OGW BG geophysical monitoring research in 2000 and 2001 through the USGS Toxic Substances Hydrology Program, borehole imaging was done as part of in situ stress-test experiments conducted at the Mirror Lake fractured rock research site in Hubbard Brook Experimental Forest, New Hampshire.

Prior to stress tests, OGW BG conducted optical imaging in a 1000-ft deep borehole. Additionally the well was inspected by a team of USGS researchers for rock type, fracture location and orientation, and hydraulic characteristics. Unfractured zones were targeted for stress-fracture experiments. After the completion of the hydro-fracing (forced fracturing of the bedrock) optical and acoustic images of the zones were collected again to record the effects of the tests. Thirteen zones were tested.

Hydraulic fracturing stress tests conducted by Steve Hickman of the USGS Geologic Discipline were designed to measure and characterize the bedrock stress fields. Determination of the ambient state of stress in the area may be a key factor in defining preferential fracture patterns and fluid transport direction.

In addition to conducting borehole optical imaging, BG also supported integrated data interpretation in the project by integrating the optical and acoustic image logs with additional borehole logging data into a single software environment to provide for a synergistic approach to data analysis and interpretation.

View the online photo gallery from this project.

Support & Collaboration

This research was conducted through the USGS Toxic Substances Hydrology Program by Carole Johnson (USGS, OGW Branch of Geophysics), Steve Hickman (USGS, Geologic Discipline), Fred Paillet (USGS, Borehole Geophysics Research Project), Roger Morin (USGS, Borehole Geophysics Research Project), and Paul Hsieh (USGS National Research Program) with assistance from OGW BG staff.

For more information:

For more information on this project, please contact Carole Johnson (Hydrologist, USGS OGW Branch of Geophysics), or call the Branch of Geophysics at (860)487-7402.

For more information about USGS Toxics Substances Hydrology Program research Mirror Lake, see the Mirror Lake Toxic Substances Hydrology Program web site. [an error occurred while processing this directive]