Borehole Development

 

Occasionally, boreholes drilled into the chalk aquifer may need to be developed to increase performance or rehabilitated due to blockage by incrustations. 

At H.D. Services we utilise three different types of development – airlifting; acidisation and BoreSaver.  This page attempts to explain the principals behind them and in which conditions each should be used.

 

AIRLIFTING: This technique is usually used when debris finds its way into the borehole and results in sediment being pulled through the borehole pumps etc.

Airlifting involves the release of compressed air within the water column causing pressure imbalance and the discharge of water at the surface.

It is imperative that compressors must be oil-free and the air must be filtered as compressors could introduce hydrocarbons into the flow.

 

ACIDISATION: This technique is used to facilitate the removal of soft material from within a chalk borehole and to open fissures in the chalk by using hydrochloric acid. This process increases the flow rate of the borehole by allowing more water from the aquifer to enter the borehole.

The introduction of an acid into an alkali environment results in a chemical reaction between the acid and the carbonate rock meaning drilling slurry (from direct circulation rotary drilling for example) is dissolved and fissures are increased in size as the acid reacts with the carbonate. This type of reaction produces large quantities of CO2. The release of this gas must be controlled at the well head with pressure relief valves.

While the process of acidisation is effective, in some cases it may not result in the yield improvement required to make the borehole commercially operational. Acidisication can significantly increase the yield of a borehole.

 

BORESAVER: BoreSaver was developed by Aquabiotics Industrial and is approved for use in private water supplies – including those used for drinking water – by the Secretary of State in the UK.

BoreSaver is used in water supply boreholes which suffer from a build-up of iron bacteria, iron oxide, manganese oxide, calcium carbonate and other minerals. These can present themselves as rusty slime and blackish/brown deposits inside pipes, cloudy/dirty/rusty water, iron build up on pumps, deposits of distinct white powder or limescale or reduced water flow.

This particular treatment can remove deposits and residue that build up and cause blockages in wells, pipes, pumps and other equipment. The BoreSaver treatment can improve the quality, output and flow of water supplies and can extend the working life of pumps and related equipment. The treatment is biodegradable and environmentally friendly.

 

If you wish to discuss your borehole development needs, please contact us.