There are various reasons for the deformation and squash of well casings. One of these is earthquakes which are caused by faults, resulting in fractures and displacement of the borehole’s tabular shape. Another reason is land subsidence which occurs due to overexploiting groundwater.
Deformation and squashing of good casings can have several negative effects, such as:
- Making voids in surrounding formations of the borehole, resulting in land subsidence.
- Collapsing gravel of filter pack into the borehole, and filling the column.
- Resulting in severe sand production and, as a result, intensifying the corrosion of pumps.
- Trapping the pump and its other accessories due to deviating from the alignment and plumpness of the borehole.
- Collapsing of sediments, including sand and gravel, into the borehole from the area of casing fracture.
The common and traditional techniques of solving these problems:
- Installing the pump higher than the damaged area.
- Flattening the casing with tapping
- Installing a secondary casing with a narrower diameter.
However, in certain situations, none of these methods may be feasible to use.