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HPT
Hydraulic Profiling Tool

How HPT works

Tap the log chart to see what it shows.Hover over the log chart to see what it shows.

When to use HPT

  • Hydrogeologic characterization (permeability and lithology)
  • In-situ remediation injection well design
  • Identification of preferential contaminant migration pathways
  • Hydrogeologic characterization on PFAS-impacted sites
  • Aquitard / confining layer mapping
  • Remediation system design and optimization
  • Hydraulic barrier and containment assessments
  • Groundwater flow path characterization
  • Supplemental data for conceptual site models

See the tool comparison if your objective is not here.

About HRSC

How HPT works

HPT measures the pressure required to inject water into the formation as the tool advances, a direct indicator of relative permeability.

  • Injection port
  • Wenner array
A line drawing of the HPT tool, measured from its photograph, moving down through alternating beds of clay and sand in a loop. Water leaves the injection port on the side of the tool: in clay it is held close to the port, and in sand it runs out into the ground. Beside the injection port a bar shows HPT injection pressure, and beside the Wenner array a bar shows electrical conductivity. Both bars are high in clay and low in sand.

Formation type

The standalone HPT uses a Wenner electrode array, which provides reliable depth resolution and strong signal stability with low sensitivity to electrical noise.

Reading HPT data

A dissipation test gives the log its static water level, and from that an estimated hydraulic conductivity.

Steps

The tool stops and the water is shut off. Pressure falls until it levels off at the groundwater pressure for that depth.

The static water level is calculated from that pressure, the depth of the test, and atmospheric pressure. Below it, water pressure rises steadily with depth.

The pressure above the absolute piezometric pressure line is what it takes to push water into the soil. With the flow rate, it gives an estimated hydraulic conductivity.

One real HPT dissipation test and the log it belongs to. On the left, injection pressure at 18.40 feet over 498 seconds: as the flow is turned off, pressure falls and levels off at 22.2 PSI. On the right, injection pressure against depth from 0 to 40 feet, with the static water level at 2.67 feet and the absolute piezometric pressure line drawn through the test reading, and beside it estimated hydraulic conductivity against the same depth, from 0 to 90 feet per day.

Contact us to add permeability profiling to your investigation program.

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