Construction bentonites are produced using a special variety of calcium bentonite with a high content of montmorillonite, with the sodium ion activated. This ensures excellent rheological and expansion properties of this bentonite – it increases its volume 5 to 20 times under the influence of water. Thanks to this property it is widely used for construction materials, mainly in sealing applications.
Construction bentonites are also used for the production of:
- asphalts dispersions,
- drilling fluids (suspensions) in tight volume excavations to stabilise the walls,
- bentonite-cement mixes used on geo-engineering for injections, sealing, and anti-filtration barriers,
- bentonite mats.
Drilling bentonites are produced using a special variety of modified bentonite. Such a formula facilitates the preparation of a suspension which has proper rheological parameters, as specified by the American Petroleum Institute. A bentonite fluid has good lubricating properties and a very high capacity for transporting excavated material irrespective of the local geological conditions.
A drilling fluid is an essential element of drilling work. If badly selected, it can cause many complications during drilling and increased costs as a result.
The functions of a drilling fluid:
- cleanses the bottom of the hole and transports the cuttings,
- balances the pressure of the rock mass,
- maintains the cuttings suspended when the drilling fluid is not being circulated,
- ensures easy cleaning of the fluid,
- cools and lubricates the drill pipe,
- stabilises the walls of the well,
- minimises harmful impact on the environment.