BOREHOLE LOGGING

Geophysical borehole logging is one of the most powerful tools for understanding fractured bedrock aquifers. By combining electrical, acoustic, temperature, and flow measurements with high-resolution borehole imaging, hydrogeologists can pinpoint where water enters and exits a well—and why.

In the images above and below, the acoustic televiewer (amplitude) and optical televiewer reveals distinct planar features cutting across the borehole wall. These sinuous, high-contrast bands represent open fractures. Their dip and azimuth can be calculated directly from the geometry of the features on the unwrapped 360° image, allowing determination of fracture orientation in geographic space. This is critical for identifying dominant fracture sets and understanding regional stress or structural controls.

Flowmeter and fluid logs add the hydraulic story. Changes in temperature and fluid conductivity, paired with vertical flow measurements, highlight active water-producing zones. In the examples shown, discrete inflow points are identified at specific depths where temperature shifts and flowmeter responses coincide with visually open fractures. Some intervals show upward or downward ambient flow within the well, indicating hydraulic head differences between fracture zones.

By integrating structure (fracture orientation) with hydraulics (flow direction and magnitude), borehole logging transforms a simple drilled hole into a detailed 3D hydrogeologic model—guiding well completion, packer testing, and sustainable groundwater development.