Well Development Techniques Part (1)

Well Development Techniques Part (1)

Well development is the process of cleaning out the clay and silt introduced during the drilling process as well as the finer part of the aquifer directly around the well screen prior to putting the well into service:-

1. Increase the rate of water flow from the aquifer into the well.
2. Stabilize the aquifer to prevent sand pumping to produce better quality water
3. Increase service life of the water pump
4. Remove organic and inorganic materials.

Types of well development techniques:

1. Chemical
2. Washing and Backwashing
3. Mechanical Surging
4. Air Development
5. Jetting

Chemical

Chemical agents are introduced into the development zone as solvents. Their action is intended to dissolve or loosen any clogging or blocking materials to make them easier to remove. The action of chemicals may also enlarge aquifer pores and improve permeability. Chemical based well development techniques can be gentle or violent in their action.

All chemical agents introduced into potable wells should be approved for such use by local authorities. Chemical methods are often used in conjunction with other well development techniques. This is particularly true when additional action is needed to break up mud cakes or flush out gelled muds. The chemical solution is allowed to stand in contact with the aquifer for the recommended soak period. After the soak period the solution is pumped or bailed from the hole. While well drilling fluids will break down naturally, the breakdown process may be enhanced by the use of chemical agents. Once degraded, the drilling fluids are much more easily pumped from the aquifer. Other chemicals may be used to break down clay smears and gelled bentonite. Chlorine breaks down polymers.

A tremie pipe can be used in conjunction with packing devices to isolate the areas of the borehole to be subjected to chemical treatment. Chemical treatment can be used to break down drilling fluids, clays and polymers. Acids are often used for improving the yield in limestone, dolomite and other calcium carbonate formations