Geophysical Mapping: Method Details
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Method Name: Fluid logging, Flow meter
Method Type:   Borehole Methods
Assigned Problems:
+ Aquifer pollution Groundwater
+ Characteristics of hazardous waste Hazardous Waste
+ Contaminant plumes Hazardous Waste
+ Fractures Groundwater
+ Groundwater table Groundwater
+ Heat mining Natural Resources
+ Host sediments, hydogeological settings Hazardous Waste
+ Landslides Natural Hazards
+ Porosity / Permeability Groundwater
+ Quality / Thickness of aquifer/aquitard Groundwater
+ Temperature Groundwater
+ Temporal variations Groundwater
   '+' = Technique applicable
Principle:   Flowmeter: records the direction and rate of vertical flow in the borehole.
Fluid-resistivity or mud-resistivity log: records the electrical resistivity or conductivity of the borehole fluid.
Fluid density: records the pressure.
Keywords:   Impeller flowmeter; packer flowmeter; fluid logging; transmissivity, permeability; flow rate; pressure; electric resistivity
  • Clear water in boreholes for flowmeter necessary
  • Exchange of drilling fluid with saline or deionised water in case of fluid logging and pumping tests necessary
  • Impeller flowmeters (most widely used) have a minimum detectable flow velocity (depending on the instrument between 0.5 - 1.5 m / min); Heat-pulse and electromagnetic flowmeters can resolve velocities of less than 3 cm / min
  • Borehole-diameter corrections are needed (caliper log)
Resolution:   Resolution between 0.5 - 1.5 m / min (depends on instrument type); Heat-pulse and electromagnetic flowmeters can resolve velocities of less than 3 cm / min
Expected Results:  
  • Measured parameter: flowmeter: vertical flow in m / s ; fluid resistivity in Ωm; conductivity in μS/cm; fluid density: kg / m3
  • Data analysis: logs: measured parameter vs. depth in m
  • Interpretation: permeability and transmissivity
Combination with other Methods:  
  • Required additional information: caliper log (correction for flowmeter logs)
  • Related add-on information: temperature log (correction for fluid-resistivity logs)
  • Independent additional information: other logs; packer tests; laboratory analyses
Operating Expense:  
  • Crew size: 1 - 2 persons
  • Acquisition speed: see ""Parameters to specify""
  • Processing: depending on problem
  • Equipment rental costs: intermediate to high
Parameters to specify:  
  • Instrument type
  • Logging speed (3 - 8 m / min; stationary)
  • Water table draw down for pumping test
QC Documents:  
  • Calibration data: last shop-calibration or on-site calibration
  • Flowmeter: repeated measurements with different acquisition speed
  • Borehole information (i.e., casing (type and length), diameter, deviation, fluid properties)
  • Complete headers
  • Field notes (e.g., all activities, effective time schedule, present personnel)
  • Field logs (displayed using specified scales)
  • Composite logs
  • Listings, histograms
  • Interpretation
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