Well Development
Well development methods aim to clear drilling debris, improve water flow, and restore natural aquifer permeability using techniques like surging, jetting, over pumping, bailing, and sometimes chemical treatments or air lifting, all designed to remove fine particles and break up bridging around the well screen for maximum water yield and clarity. Common approaches involve creating high-velocity flow reversals or high flow rates to dislodge sediments, often combined to effectively clean the borehole and surrounding formation.
Common Well Development Methods
1. Surging (Mechanical/Air):
Using a surge block (plunger) or compressed air to rapidly push water back and forth into the formation, breaking up sand bridges and cleaning the screen.
2. Over pumping:
Pumping water at rates higher than normal to flush out fine particles and stabilize the well, though less effective alone.
3. Jetting (Air/Water):
Injecting high-pressure air or water into the well to dislodge fine materials and encourage flow, sometimes combined with pumping.
4. Backwashing/Back-Lashing:
Forcing water or air back up the well to dislodge fines, often with the pump.
5. Chemical Treatment:
Using chlorine (for disinfection) or surfactants (silt breakers) to break down clays and improve water flow, followed by flushing.
6. Air Lifting:
Using compressed air to lift water and sediment out of the well.
7. Hydraulic Fracturing/Shooting:
Specialized techniques using explosives or high-pressure fluids to create fractures in hard rock formations, increasing permeability (less common).
Key Principle :
Flow Reversal & Velocity
Most effective methods rely on creating high water velocities and flow reversals (back-and-forth motion) to move fine sand grains away from the screen, preventing them from bridging and clogging the well, which a simple, one-directional pump flow cannot achieve alone.