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21 Common Borehole Technical Terms with Pictures 2023

In this article you will get to know in simplicity some common borehole technical terms. This will guide you while you are undertaking drilling at a personal or community level. Illustrations are in pictures for ease of understanding. Some know how doesn't hurt!




General Borehole Layout
Borehole Layout: Image credit- Edwin N.

The image above shows the general outline of a borehole.

Borehole layout with labels
Borehole Layout with Labels: Image credit - Edwin N

An alternative view with similar layouts.

Borehole acronyms explained with pictures
Borehole Pumping Process and Acronyms Explained: Image credit - Edwin N

This image captures the acronyms and the general pumping process; image credits: Edwin N.

Simplified representation of an aquifer
Simplified Aquifer: Image credit - Edwin N

A simplified view of an aquifer; image credit: Edwin N.

  1. Aquifer – Water bearing material in the sub-surface below the water table.
  2. Bgl – Below Ground Level; term used for depth inside borehole
  3. Pwl – Pumped Water Level; water level during continuous pumping
  4. Drawdown (S)– difference in water level before and during continuous pumping
  5. Pump – mechanical tool used to raise water in the borehole to the surface for storage purposes
  6. Wsl – Water Strike Level; the depth that an aquifer is encountered during borehole drilling
  7. Wrl – Water Rest Level; the level water rises to before pumping
  8. Q (yield) – measured discharge of water from a borehole in LPM (Litres per minute or (Cubic Meters)
  9. Bentonite seal – Special type of clay (poor permeability) used to seal the borehole annulus close to the surface to avoid contamination
  10. Annulus – the difference in diameter from the installed casing and the drilled hole
  11. Gravel – well rounded inert material used to fill the borehole annulus to improve water filtration and borehole wall stability
  12. Draw pipes – pvc pipes connected to the pump for water discharge to the surface
  13. Casing -pvc or mild steel installed in the borehole to stabilize the borehole wall and for protecting downhole borehole equipment
  14. Screens – casings with perforations allowing water into the borehole in the aquifer zones
  15. Back fill – the depth filled by collapsing material in the borehole from the total drilled depth
  16. Azimuth – orientation of the drilled hole vertical or directional
  17. Cuttings – the soil and rock material removed from the borehole during drilling for inspection by a geologist
  18. Pumping head (H)– the total distance from the surface to the pump intake depth
  19. Pump intake – the depth below ground level where the pump is installed
  20. Recovery – the rate at which the water level in a borehole rises to the WRL after continuous pumping
  21. Abstraction -  pumping water from the borehole for use or storage at the surface


We are done with the technical, if you have any difficulties click here.


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Comments

  1. Timithy25 November 2023 at 09:14

    That's very impressive. It gives those interested a know how on procedural navigation; be it a client or a novice in the field.

    ReplyDelete

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