To keep loose sand and gravel from collapsing into the borehole, it is necessary to use Borehole Casing.
Borehole Casing supports the Borehole walls while allowing water to enter. This means that the casing must be strong enough to withstand underground pressures. This is why at Nakiso Borehole Drilling, our preferred Borehole Casing is Class 9 and Class 10.
This is because Class 9 and Class 10 Casings are more collapses resistant. The strength of a Casing is often described as collapse resistance.
Formation Stress:
The Borehole Casing can be deformed by external pressures arising from changes in the
rock and soils outside the borehole. The drilling of a borehole alters pressures underground and also exposes rocks or formations that expand when hydrated.
For example, some clays and shales can swell when exposed to water. It depends upon the
chemistry of the clay or shale, and the chemistry of the water.
 |
| Why Do Boreholes Collapse? - Borehole Drilling In Zimbabwe! |
The annular space around
the Borehole Casing is often very small. Therefore the swelling does not need to be large
before the clay or shale touches and begins to exert pressure on the Borehole Casing. The swelling
can deform the casing, particularly if the pressure from the clay or shale is confined, by a
sealed annulus above and below the formation. In other words, the shale or clay can only
expand laterally.
The Borehole Casing can be deformed even if there is a gravel pack between
the shale or clay and the casing. The pressure is exerted against the gravel pack, which, in turn, transfers the pressure onto the casing.
 |
| Borehole Casing In Zimbabwe - Why Do Boreholes Collapse? |
With this in minds, it is important to consider the integrity of the Borehole Casing. This is why we encourage you to always choose to have your borehole Cased with Class 9 and Class 10 Casings since they are more collapse resistant.
 |
| Why Do Boreholes Collapse? - Borehole Drilling In Zimbabwe! |
The strength of a Casing is often described as collapse resistance.
As Nakiso Borehole Drilling - Our Prefered Borehole Casing Is Class 9 and Class 10 (Pressure Classes.)
For All Your Borehole Drilling Services Contact Us:
Five Facts About Borehole Drilling That You Need To Take Note Of:
1. Know Your Borehole Casings:The Preferred Borehole Casing In Zimbabwe Is Class 9 and 10 (Pressure Classes.)This is because Class 9 and Class 10 Casings are more collapse resistant. The strength of a Casing is often described as collapse resistance.
2. Borehole Drilling Depth: The exact depth, of where the water is located, cannot be established by the drilling contractor nor the Water Surveyor (Borehole Siter).
3. The Is No 100% Guarantee On Water: It is important to note that it is never a 100% guarantee that any hole will yield water, the amount and water quality can also not be guaranteed by the drilling contractor and water surveyor.
4. Borehole Siting or Water Surveying Is Important: Making use of a hydrologist or traditional water diviner will increase your chances of having a successful borehole that will yield a sufficient amount of water.
5. Know The Risks: The risk of the borehole drilling lies with the property owner. The client will still be liable for the drilling costs irrespective of a borehole yielding water or not.
Your smile is our commitment!
Business Offices: 65 Churchill Avenue, Alexandra Park, Harare North, Zimbabwe.
Call Us Today:
Office Numbers: +263 867 71 88844
Sales: +263 78 860 8009
Operations: +263 78 860 8005
Marketing: +263 78 876 6701
Email: info@nakisoboreholes.co.zw
Website: www.nakisoboreholes.co.zw
