The company was appointed by the client to carry out the drilling and testing of two trial boreholes on an existing council development. The successful borehole would be later incorporated into a larger ground source energy scheme to provide approximately 500 kW of heating and cooling for the replacement residential blocks.

THE WORKS
For the trial, 2 No. 135 m deep chalk wells were drilled using direct circulation techniques at 475 mm diameter. A permanent steel casing of 340 mm diameter was installed and sealed into the top of the Chalk aquifer at depth of approximately 82 m, with the remainder of the borehole left as an open-hole section through the competent Chalk. 

Boreholes were acidised to improve the yield.  A series of pumping tests were carried out as part of the trail, including step tests, constant rate tests and reinjections tests on the single pair of boreholes.