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Borehole Geophysical Surveys / +44 (0)1939 210 710

Borehole Magnetic Resonance (BMR) Tool

These tools measure the amount of water present in the pore space using permanent magnets and antenna, similar to an MRi machine in a hospital. The lithology independent techniques results in water (moisture) content above the water table and total porosity and pore size distribution below the water table.

BMR can provide secondary measurements such as specific yield (amount of moveable water) and specific retention (amount of bound water) as well as calculate estimates for hydraulic conductivity with additional information. The tool can measure through PVC, fiberglass or open hole conditions in dry or water filled boreholes and can be used in a range of sectors from hydrogeology to mining.

Features and benefits

  • Lithology independent measurement of water content/total porosity and pore size distribution
  • Lithology dependent measurements such as moveable and bound porosity and hydraulic conductivity/permeability
  • As part of an integrated logging solution, BMR can combine with other logs in Geotechnical, Hydrogeology, Mining and Geothermal applications
  • Completely safe-no chemical sources or radiation
The total BMR measured echo delay is the sum of the contribution from a range of different pores in the measured region. The inversion process to T2 time solves for the amount of porosity associated with a particular T2-time, resulting in the pore size 9T2) distribution.
Standard BMR log output. From the left, Track 1 contains a gamma ray curve, typically run with the BMR tool for depth control. Track 2 contains the lithology-independent total BMR porosity 9TPOR). Track 3 contains measured T2 distribution as well as the logarithmic mean T2 value. Track 4 contains volumes of clay bound water, and free fluid derived from the measured T2 distribution. Track 5 contains hydraulic conductivity estimates using both the Timur-Coates and the SDR permeability equations.


Tool size 210 x 60mm 2160 x 90mm
Tool weight 19.7kg 26kg
Max. Pressure 200 bar 200 bar
Max Temperature 80˚C 80˚C
Hole sizes 75-186mm 122-312mm
Borehole Condition Open hole, Fibreglass, PVC casing Dry or fluid filled Open hole, Fibreglass, PVC casing Dry or fluid filled
Logging Condition 0.5 to 1.1 metre/min. Free running 0.5 to 1.1 metre/min. Free running