Pipe installation and monitoring
Having drilled a borehole, if desired, various pipes can then be installed to allow for future gas and/or water levels to be monitored. Standard pipe sizes are 50 and 38mm and consist of slotted and plain sections. The slotted section should be placed from the base of the hole up to typically 1m below ground level and then the plain section from there to the top. Pea shingle is placed around the slots and geosock can also be used if there is a risk of silting up of the pipe. A bentonite seal is then used to prevent surface water penetrating the pipe and a bung with gas tap placed on top. The well can be finished with a stopcock cover to provide protection and future access and left flush with the ground level. Upright covers can be placed on sites such as grassed or cropped fields where the installation needs to be visible.
Borehole pressure and flow
We can monitor our own or others borehole installation wells. A small, portable, calibrated gas analyser is used to determine the presence of any borehole pressure and flow as well as gases such as CH4, CO2, O2, H2S, CO, atmospheric pressure and temperature. Water levels are determined using a dip meter and samples can then be obtained using either a bailer or waterra pipe and valve.
